Replace mt_rand with <random>

Also add some utility methods and classes.

27 files changed, 454 insertions, 1671 deletions

diff --git a/src/common/core.cpp b/src/common/core.cpp
index ae0e3eb..994de93 100644
--- a/src/common/core.cpp
+++ b/src/common/core.cpp
@@ -8,7 +8,7 @@
 #include <cstdlib>
 #include <ctime>
 
-#include "mt_rand.hpp"
+#include "random.hpp"
 #include "socket.hpp"
 #include "timer.hpp"
 
@@ -68,9 +68,6 @@ bool runflag = true;
  */
 int main(int argc, char **argv)
 {
-    /// Note that getpid() and getppid() may be very close
-    mt_seed(time(NULL) ^ (getpid() << 16) ^ (getppid() << 8));
-
     do_socket();
 
     do_init(argc, argv);
diff --git a/src/common/md5calc.cpp b/src/common/md5calc.cpp
index c9c2415..1625912 100644
--- a/src/common/md5calc.cpp
+++ b/src/common/md5calc.cpp
@@ -2,7 +2,7 @@
 
 #include <cstring>
 
-#include "mt_rand.hpp"
+#include "random.hpp"
 
 #include "../poison.hpp"
 
@@ -305,8 +305,9 @@ const char *MD5_saltcrypt(const char *key, const char *salt)
 
 const char *make_salt(void) {
     static char salt[6];
-    for (int i=0; i<5; i++)
-        salt[i] = MPRAND(48, 78);
+    for (int i = 0; i < 5; i++)
+        // 126 would probably actually be okay
+        salt[i] = random_::in(48, 125);
     return salt;
 }
 
diff --git a/src/common/mt_rand.cpp b/src/common/mt_rand.cpp
deleted file mode 100644
index fbbf71f..0000000
--- a/src/common/mt_rand.cpp
+++ /dev/null
@@ -1,123 +0,0 @@
-/*
-// This is the ``Mersenne Twister'' random number generator MT19937, which
-// generates pseudorandom integers uniformly distributed in 0..(2^32 - 1)
-// starting from any odd seed in 0..(2^32 - 1).  This version is a recode
-// by Shawn Cokus (Cokus@math.washington.edu) on March 8, 1998 of a version by
-// Takuji Nishimura (who had suggestions from Topher Cooper and Marc Rieffel in
-// July-August 1997).
-//
-// Effectiveness of the recoding (on Goedel2.math.washington.edu, a DEC Alpha
-// running OSF/1) using GCC -O3 as a compiler: before recoding: 51.6 sec. to
-// generate 300 million random numbers; after recoding: 24.0 sec. for the same
-// (i.e., 46.5% of original time), so speed is now about 12.5 million random
-// number generations per second on this machine.
-//
-// According to the URL <http://www.math.keio.ac.jp/~matumoto/emt.html>
-// (and paraphrasing a bit in places), the Mersenne Twister is ``designed
-// with consideration of the flaws of various existing generators,'' has
-// a period of 2^19937 - 1, gives a sequence that is 623-dimensionally
-// equidistributed, and ``has passed many stringent tests, including the
-// die-hard test of G. Marsaglia and the load test of P. Hellekalek and
-// S. Wegenkittl.''  It is efficient in memory usage (typically using 2506
-// to 5012 bytes of static data, depending on data type sizes, and the code
-// is quite short as well).  It generates random numbers in batches of 624
-// at a time, so the caching and pipelining of modern systems is exploited.
-// It is also divide- and mod-free.
-//
-// This library is free software; you can redistribute it and/or modify it
-// under the terms of the GNU Library General Public License as published by
-// the Free Software Foundation (either version 2 of the License or, at your
-// option, any later version).  This library is distributed in the hope that
-// it will be useful, but WITHOUT ANY WARRANTY, without even the implied
-// warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
-// the GNU Library General Public License for more details.  You should have
-// received a copy of the GNU Library General Public License along with this
-// library; if not, write to the Free Software Foundation, Inc., 59 Temple
-// Place, Suite 330, Boston, MA 02111-1307, USA.
-//
-// The code as Shawn received it included the following notice:
-//
-//   Copyright (C) 1997 Makoto Matsumoto and Takuji Nishimura.  When
-//   you use this, send an e-mail to <matumoto@math.keio.ac.jp> with
-//   an appropriate reference to your work.
-//
-// It would be nice to CC: <Cokus@math.washington.edu> when you write.
-//
-*/
-
-#include "mt_rand.hpp"
-
-#include <ctime>
-
-#include "../poison.hpp"
-
-#define N              624                  // length of state vector
-#define M              397                  // a period parameter
-#define K              0x9908B0DFU          // a magic constant
-
-#define hiBit(u)       ((u) & 0x80000000U)  // mask all but highest bit of u
-#define loBit(u)       ((u) & 0x00000001U)  // mask all but lowest bit of u
-#define loBits(u)      ((u) & 0x7FFFFFFFU)  // mask the highest bit of u
-#define mixBits(u, v)  (hiBit(u)|loBits(v)) // move hi bit of u to hi bit of v
-
-static
-uint32_t state[N+1]; // state vector the +1 is needed due to the coding
-static
-uint32_t *next;      // next random value is computed from here
-static
-int left = -1;       // can *next++ this many times before reloading
-
-void mt_seed(uint32_t seed)
-{
-    uint32_t x = seed | 1U;
-    uint32_t *s = state;
-    left = 0;
-
-    for (int j = N; *s++ = x, --j; x *= 69069U);
-}
-
-static
-void mt_reload(void)
-{
-    // if mt_seed has never been called
-    if (left < -1)
-        mt_seed(time(NULL));
-
-    // conceptually, these are indices into the state that wrap
-    uint32_t *p0 = state;
-    uint32_t *p2 = state + 2;
-    uint32_t *pM = state + M;
-
-    uint32_t s0 = state[0];
-    uint32_t s1 = state[1];
-
-    // regenerate the lower N-M elements of the state
-    for (int j = N-M+1; --j != 0; s0 = s1, s1 = *p2++)
-        *p0++ = *pM++ ^ (mixBits(s0, s1) >> 1) ^ (loBit(s1) ? K : 0U);
-
-    pM = state;
-    // regenerate the next M-1 elements of the state
-    // note that s1 is set to state[N] at the end, but discarded
-    for (int j = M; --j != 0; s0 = s1, s1 = *p2++)
-        *p0++ = *pM++ ^ (mixBits(s0, s1) >> 1) ^ (loBit(s1) ? K : 0U);
-
-    // regenerate the last 1 element of the state
-    s1 = state[0];
-    *p0 = *pM ^ (mixBits(s0, s1) >> 1) ^ (loBit(s1) ? K : 0U);
-
-    // ready for the normal mt_random algorithm
-    left = N;
-    next = state;
-}
-
-uint32_t mt_random(void)
-{
-    if (--left < 0)
-        mt_reload();
-
-    uint32_t y = *next++;
-    y ^= (y >> 11);
-    y ^= (y << 7) & 0x9D2C5680U;
-    y ^= (y << 15) & 0xEFC60000U;
-    return y ^ (y >> 18);
-}
diff --git a/src/common/mt_rand.hpp b/src/common/mt_rand.hpp
deleted file mode 100644
index ae5986b..0000000
--- a/src/common/mt_rand.hpp
+++ /dev/null
@@ -1,24 +0,0 @@
-#ifndef MT_RAND_HPP
-#define MT_RAND_HPP
-
-# include "sanity.hpp"
-
-/// Initialize the generator (called automatically with time() if you don't)
-void mt_seed(uint32_t seed);
-/// Get a random number
-uint32_t mt_random(void);
-
-/**
- * ModuloRand and ModuloPlusRand
- * These macros are used to replace the vast number of calls to rand()%mod
- * TODO eliminate the rest of the calls to rand()
- * MRAND(10)    returns 0..9
- * MPRAND(5,10) returns 5..14
- */
-// The cast is essential because the result is sometimes
-// compared with a possibly negative number.
-// Because it's using modulus, high numbers shouldn't happen anyway.
-# define MRAND(mod) ((int)(mt_random() % (mod)))
-# define MPRAND(add, mod) ((add) + MRAND(mod))
-
-#endif // MT_RAND_HPP
diff --git a/src/common/random.cpp b/src/common/random.cpp
new file mode 100644
index 0000000..273dcec
--- /dev/null
+++ b/src/common/random.cpp
@@ -0,0 +1,8 @@
+#include "random2.hpp"
+
+#include "../poison.hpp"
+
+namespace random_
+{
+    std::mt19937 generate{std::random_device()()};
+} // namespace random_
diff --git a/src/common/random.hpp b/src/common/random.hpp
new file mode 100644
index 0000000..44057ed
--- /dev/null
+++ b/src/common/random.hpp
@@ -0,0 +1,69 @@
+#ifndef RANDOM_HPP
+#define RANDOM_HPP
+
+# include "random.t.hpp"
+
+# include "sanity.hpp"
+
+# include <random>
+
+// This is not namespace random since that collides with a C function,
+// but this can be revisited when everything goes into namespace tmwa.
+namespace random_
+{
+    /// Get a random number from 0 .. 2**32 - 1
+    extern std::mt19937 generate;
+
+    /// Get a random number from 0 .. bound - 1
+    inline
+    int to(int bound)
+    {
+        std::uniform_int_distribution<int> dist(0, bound - 1);
+        return dist(generate);
+    }
+
+    /// Get a random number from low .. high (inclusive!)
+    inline
+    int in(int low, int high)
+    {
+        std::uniform_int_distribution<int> dist(low, high);
+        return dist(generate);
+    }
+
+    inline
+    bool coin()
+    {
+        // sigh, can't specify <bool> directly ...
+        std::uniform_int_distribution<int> dist(false, true);
+        return dist(generate);
+    }
+
+    inline
+    bool chance(Fraction f)
+    {
+        if (f.num <= 0)
+            return false;
+        if (f.num >= f.den)
+            return true;
+        return random_::to(f.den) < f.num;
+    }
+
+    // C is usually one of:
+    //  std::vector<T>
+    //  std::initializer_list<T>
+    //  std::array<T, n>
+    template<class C>
+    auto choice(C&& c) -> decltype(*c.begin())
+    {
+        return *(c.begin() + random_::to(c.size()));
+    }
+
+    // allow bare braces
+    template<class T>
+    T choice(std::initializer_list<T>&& il)
+    {
+        return random_::choice(il);
+    }
+} // namespace random_
+
+#endif // RANDOM_HPP
diff --git a/src/common/random.t.hpp b/src/common/random.t.hpp
new file mode 100644
index 0000000..98a6c59
--- /dev/null
+++ b/src/common/random.t.hpp
@@ -0,0 +1,23 @@
+#ifndef RANDOM_T_HPP
+#define RANDOM_T_HPP
+
+namespace random_
+{
+    struct Fraction
+    {
+        int num, den;
+    };
+
+    template<class T, T den>
+    struct Fixed
+    {
+        T num;
+
+        operator Fraction()
+        {
+            return {num, den};
+        }
+    };
+} // namespace random_
+
+#endif // RANDOM_T_HPP
diff --git a/src/common/random2.hpp b/src/common/random2.hpp
new file mode 100644
index 0000000..86deddf
--- /dev/null
+++ b/src/common/random2.hpp
@@ -0,0 +1,74 @@
+#ifndef RANDOM2_HPP
+#define RANDOM2_HPP
+
+# include "random.hpp"
+# include "utils2.hpp"
+
+# include <algorithm>
+
+namespace random_
+{
+    namespace detail
+    {
+        struct RandomIterator
+        {
+            int bound;
+            int current;
+            bool frist;
+
+            void operator ++()
+            {
+                frist = false;
+                // TODO: reimplement in terms of LFSRs, so that certain
+                // blockage patterns don't favor adjacent cells.
+                current = current + 1;
+                if (current == bound)
+                    current = 0;
+            }
+            int operator *()
+            {
+                return current;
+            }
+        };
+
+        inline
+        bool operator == (RandomIterator l, RandomIterator r)
+        {
+            return l.current == r.current && l.frist == r.frist;
+        }
+
+        inline
+        bool operator != (RandomIterator l, RandomIterator r)
+        {
+            return !(l == r);
+        }
+    }
+
+    /// Yield every cell from 0 .. bound - 1 in some order.
+    /// The starting position is random, but not the order itself.
+    ///
+    /// Expected usage:
+    ///     for (int i : random_::iterator(vec.size()))
+    ///         if (vec[i].okay())
+    ///             return frob(vec[i]);
+    inline
+    IteratorPair<detail::RandomIterator> iterator(int bound)
+    {
+        int current = random_::to(bound);
+        return
+        {
+            detail::RandomIterator{bound, current, true},
+            detail::RandomIterator{bound, current, false}
+        };
+    }
+
+    /// similar to std::random_shuffle(c.begin(), c.end()), but guaranteed
+    /// to use a good source of randomness.
+    template<class C>
+    void shuffle(C&& c)
+    {
+        std::random_shuffle(c.begin(), c.end(), random_::to);
+    }
+} // namespace random_
+
+#endif // RANDOM2_HPP
diff --git a/src/login/login.cpp b/src/login/login.cpp
index e2b64b8..94ae4b5 100644
--- a/src/login/login.cpp
+++ b/src/login/login.cpp
@@ -20,7 +20,7 @@
 #include "../common/lock.hpp"
 #include "../common/md5calc.hpp"
 #include "../common/mmo.hpp"
-#include "../common/mt_rand.hpp"
+#include "../common/random.hpp"
 #include "../common/socket.hpp"
 #include "../common/timer.hpp"
 #include "../common/version.hpp"
@@ -1046,8 +1046,8 @@ int mmo_auth(struct mmo_account *account, int fd)
     stamp_time(tmpstr);
 
     account->account_id = auth_dat[i].account_id;
-    account->login_id1 = mt_random();
-    account->login_id2 = mt_random();
+    account->login_id1 = random_::generate();
+    account->login_id2 = random_::generate();
     memcpy(account->lastlogin, auth_dat[i].lastlogin, 24);
     memcpy(auth_dat[i].lastlogin, tmpstr, 24);
     account->sex = auth_dat[i].sex;
@@ -3291,9 +3291,9 @@ void parse_login(int fd)
                 // TODO fix or get rid of this
                 // Creation of the coding key
                 memset(ld->md5key, '\0', sizeof(ld->md5key));
-                ld->md5keylen = MRAND(4) + 12;
+                ld->md5keylen = random_::in(12, 15);
                 for (int i = 0; i < ld->md5keylen; i++)
-                    ld->md5key[i] = MRAND(255) + 1;
+                    ld->md5key[i] = random_::in(1, 255);
 
                 RFIFOSKIP(fd, 2);
                 WFIFOW(fd, 0) = 0x01dc;
diff --git a/src/map/atcommand.cpp b/src/map/atcommand.cpp
index 6c82e65..479b7c3 100644
--- a/src/map/atcommand.cpp
+++ b/src/map/atcommand.cpp
@@ -7,7 +7,7 @@
 #include "../common/core.hpp"
 #include "../common/cxxstdio.hpp"
 #include "../common/mmo.hpp"
-#include "../common/mt_rand.hpp"
+#include "../common/random.hpp"
 #include "../common/nullpo.hpp"
 #include "../common/socket.hpp"
 #include "../common/timer.hpp"
@@ -127,8 +127,6 @@ ATCOMMAND_FUNC(enablenpc);
 ATCOMMAND_FUNC(disablenpc);
 ATCOMMAND_FUNC(servertime);    // by Yor
 ATCOMMAND_FUNC(chardelitem);   // by Yor
-ATCOMMAND_FUNC(jail);          // by Yor
-ATCOMMAND_FUNC(unjail);        // by Yor
 ATCOMMAND_FUNC(ignorelist);    // by Yor
 ATCOMMAND_FUNC(charignorelist);    // by Yor
 ATCOMMAND_FUNC(inall);         // by Yor
@@ -291,8 +289,6 @@ AtCommandInfo atcommand_info[] = {
     {AtCommand_ServerTime, "@servertime", 0, atcommand_servertime}, // by Yor
     {AtCommand_CharDelItem, "@chardelitem", 60, atcommand_chardelitem}, // by Yor
     {AtCommand_ListNearby, "@listnearby", 40, atcommand_list_nearby},   // by Yor
-    {AtCommand_Jail, "@jail", 60, atcommand_jail},  // by Yor
-    {AtCommand_UnJail, "@unjail", 60, atcommand_unjail},    // by Yor
     {AtCommand_IgnoreList, "@ignorelist", 0, atcommand_ignorelist}, // by Yor
     {AtCommand_CharIgnoreList, "@charignorelist", 20, atcommand_charignorelist},    // by Yor
     {AtCommand_IgnoreList, "@inall", 20, atcommand_inall},  // by Yor
@@ -689,9 +685,9 @@ int atcommand_charwarp(const int fd, struct map_session_data *sd,
     }
 
     if (x <= 0)
-        x = MRAND(399) + 1;
+        x = random_::in(1, 399);
     if (y <= 0)
-        y = MRAND(399) + 1;
+        y = random_::in(1, 399);
     if (strstr(map_name, ".gat") == NULL && strstr(map_name, ".afm") == NULL && strlen(map_name) < 13)   // 16 - 4 (.gat)
         strcat(map_name, ".gat");
 
@@ -770,9 +766,9 @@ int atcommand_warp(const int fd, struct map_session_data *sd,
     }
 
     if (x <= 0)
-        x = MRAND(399) + 1;
+        x = random_::in(1, 399);
     if (y <= 0)
-        y = MRAND(399) + 1;
+        y = random_::in(1, 399);
 
     if (strstr(map_name, ".gat") == NULL && strstr(map_name, ".afm") == NULL && strlen(map_name) < 13)   // 16 - 4 (.gat)
         strcat(map_name, ".gat");
@@ -904,9 +900,9 @@ int atcommand_jump(const int fd, struct map_session_data *sd,
     sscanf(message, "%d %d", &x, &y);
 
     if (x <= 0)
-        x = MRAND(399) + 1;
+        x = random_::in(1, 399);
     if (y <= 0)
-        y = MRAND(399) + 1;
+        y = random_::in(1, 399);
     if (x > 0 && x < 800 && y > 0 && y < 800)
     {
         if (sd->bl.m >= 0 && map[sd->bl.m].flag.nowarpto
@@ -2199,13 +2195,14 @@ int atcommand_spawn(const int fd, struct map_session_data *sd,
         j = 0;
         k = 0;
         while (j++ < 8 && k == 0)
-        {                       // try 8 times to spawn the monster (needed for close area)
+        {
+            // try 8 times to spawn the monster (needed for close area)
             if (x <= 0)
-                mx = sd->bl.x + (MRAND(range) - (range / 2));
+                mx = sd->bl.x + random_::in(-range / 2, range / 2 );
             else
                 mx = x;
             if (y <= 0)
-                my = sd->bl.y + (MRAND(range) - (range / 2));
+                my = sd->bl.y + random_::in(-range / 2, range / 2);
             else
                 my = y;
             k = mob_once_spawn(sd, "this", mx, my, "", mob_id, 1, "");
@@ -4867,125 +4864,6 @@ int atcommand_chardelitem(const int fd, struct map_session_data *sd,
 }
 
 /*==========================================
- * @jail <char_name> by [Yor]
- * Special warp! No check with nowarp and nowarpto flag
- *------------------------------------------
- */
-int atcommand_jail(const int fd, struct map_session_data *sd,
-                    const char *, const char *message)
-{
-    char character[100];
-    struct map_session_data *pl_sd;
-    int x, y;
-
-    memset(character, '\0', sizeof(character));
-
-    if (!message || !*message || sscanf(message, "%99[^\n]", character) < 1)
-    {
-        clif_displaymessage(fd,
-                             "Please, enter a player name (usage: @jail <char_name>).");
-        return -1;
-    }
-
-    if ((pl_sd = map_nick2sd(character)) != NULL)
-    {
-        if (pc_isGM(sd) >= pc_isGM(pl_sd))
-        {                       // you can jail only lower or same GM
-            switch (MRAND(2))
-            {
-                case 0:
-                    x = 24;
-                    y = 75;
-                    break;
-                default:
-                    x = 49;
-                    y = 75;
-                    break;
-            }
-            if (pc_setpos(pl_sd, "sec_pri.gat", x, y, BeingRemoveWhy::WARPED) == 0)
-            {
-                pc_setsavepoint(pl_sd, "sec_pri.gat", x, y);   // Save Char Respawn Point in the jail room [Lupus]
-                clif_displaymessage(pl_sd->fd, "GM has send you in jails.");
-                clif_displaymessage(fd, "Player warped in jails.");
-            }
-            else
-            {
-                clif_displaymessage(fd, "Map not found.");
-                return -1;
-            }
-        }
-        else
-        {
-            clif_displaymessage(fd, "Your GM level don't authorise you to do this action on this player.");
-            return -1;
-        }
-    }
-    else
-    {
-        clif_displaymessage(fd, "Character not found.");
-        return -1;
-    }
-
-    return 0;
-}
-
-/*==========================================
- * @unjail/@discharge <char_name> by [Yor]
- * Special warp! No check with nowarp and nowarpto flag
- *------------------------------------------
- */
-int atcommand_unjail(const int fd, struct map_session_data *sd,
-                      const char *, const char *message)
-{
-    char character[100];
-    struct map_session_data *pl_sd;
-
-    memset(character, '\0', sizeof(character));
-
-    if (!message || !*message || sscanf(message, "%99[^\n]", character) < 1)
-    {
-        clif_displaymessage(fd,
-                             "Please, enter a player name (usage: @unjail/@discharge <char_name>).");
-        return -1;
-    }
-
-    if ((pl_sd = map_nick2sd(character)) != NULL)
-    {
-        if (pc_isGM(sd) >= pc_isGM(pl_sd))
-        {                       // you can jail only lower or same GM
-            if (pl_sd->bl.m != map_mapname2mapid("sec_pri.gat"))
-            {
-                clif_displaymessage(fd, "This player is not in jails.");
-                return -1;
-            }
-            else if (pc_setpos(pl_sd, "prontera.gat", 156, 191, BeingRemoveWhy::WARPED) == 0)
-            {
-                pc_setsavepoint(pl_sd, "prontera.gat", 156, 191);  // Save char respawn point in Prontera
-                clif_displaymessage(pl_sd->fd, "GM has discharge you.");
-                clif_displaymessage(fd, "Player warped to Prontera.");
-            }
-            else
-            {
-                clif_displaymessage(fd, "Map not found.");
-                return -1;
-            }
-        }
-        else
-        {
-            clif_displaymessage(fd, "Your GM level don't authorise you to do this action on this player.");
-            return -1;
-        }
-    }
-    else
-    {
-        clif_displaymessage(fd, "Character not found.");
-        return -1;
-    }
-
-    return 0;
-}
-
-/*==========================================
  * @broadcast by [Valaris]
  *------------------------------------------
  */
@@ -6191,8 +6069,8 @@ int atcommand_summon(const int, struct map_session_data *sd,
     if (mob_id == 0)
         return -1;
 
-    x = sd->bl.x + (MRAND(10) - 5);
-    y = sd->bl.y + (MRAND(10) - 5);
+    x = sd->bl.x + random_::in(-5, 4);
+    y = sd->bl.y + random_::in(-5, 4);
 
     id = mob_once_spawn(sd, "this", x, y, "--ja--", mob_id, 1, "");
     if ((md = (struct mob_data *) map_id2bl(id)))
diff --git a/src/map/battle.cpp b/src/map/battle.cpp
index fe8dfe4..dad78cb 100644
--- a/src/map/battle.cpp
+++ b/src/map/battle.cpp
@@ -5,7 +5,7 @@
 #include <fstream>
 
 #include "../common/cxxstdio.hpp"
-#include "../common/mt_rand.hpp"
+#include "../common/random.hpp"
 #include "../common/nullpo.hpp"
 
 #include "clif.hpp"
@@ -133,12 +133,6 @@ int battle_get_max_hp(struct block_list *bl)
         if (bl->type == BL::MOB && ((struct mob_data *) bl))
         {
             max_hp = ((struct mob_data *) bl)->stats[mob_stat::MAX_HP];
-            if (mob_db[((struct mob_data *) bl)->mob_class].mexp > 0)
-            {
-                if (battle_config.mvp_hp_rate != 100)
-                    max_hp = (max_hp * battle_config.mvp_hp_rate) / 100;
-            }
-            else
             {
                 if (battle_config.monster_hp_rate != 100)
                     max_hp = (max_hp * battle_config.monster_hp_rate) / 100;
@@ -816,23 +810,6 @@ MobMode battle_get_mode(struct block_list *bl)
     return MobMode::CAN_MOVE;
 }
 
-int battle_get_mexp(struct block_list *bl)
-{
-    nullpo_ret(bl);
-    if (bl->type == BL::MOB)
-    {
-        const struct mob_data *mob = (struct mob_data *) bl;
-        const int retval =
-            (mob_db[mob->mob_class].mexp *
-             (int)(mob->stats[mob_stat::XP_BONUS])) >> MOB_XP_BONUS_SHIFT;
-        FPRINTF(stderr, "Modifier of %x: -> %d\n", mob->stats[mob_stat::XP_BONUS],
-                 retval);
-        return retval;
-    }
-    else
-        return 0;
-}
-
 int battle_get_stat(SP stat_id, struct block_list *bl)
 {
     switch (stat_id)
@@ -1154,7 +1131,7 @@ struct Damage battle_calc_mob_weapon_attack(struct block_list *src,
 
     if ((skill_num == SkillID::ZERO)
         && skill_lv >= 0 && battle_config.enemy_critical
-        && (MRAND(1000)) < cri)
+        && random_::chance({cri, 1000}))
         // 判定（スキルの場合は無視）
         // 敵の判定
     {
@@ -1166,7 +1143,7 @@ struct Damage battle_calc_mob_weapon_attack(struct block_list *src,
         int vitbonusmax;
 
         if (atkmax > atkmin)
-            damage += atkmin + MRAND((atkmax - atkmin + 1));
+            damage += random_::in(atkmin, atkmax);
         else
             damage += atkmin;
 
@@ -1238,18 +1215,11 @@ struct Damage battle_calc_mob_weapon_attack(struct block_list *src,
                 t_def = def2 * 8 / 10;
 
                 vitbonusmax = (t_vit / 20) * (t_vit / 20) - 1;
-                if (battle_config.monster_defense_type)
                 {
-                    damage =
-                        damage - (def1 * battle_config.monster_defense_type) -
-                        t_def -
-                        ((vitbonusmax < 1) ? 0 : MRAND((vitbonusmax + 1)));
-                }
-                else
-                {
-                    damage =
-                        damage * (100 - def1) / 100 - t_def -
-                        ((vitbonusmax < 1) ? 0 : MRAND((vitbonusmax + 1)));
+                    damage = damage * (100 - def1) / 100;
+                    damage -= t_def;
+                    if (vitbonusmax > 0)
+                       damage -= random_::in(0, vitbonusmax);
                 }
             }
         }
@@ -1263,7 +1233,7 @@ struct Damage battle_calc_mob_weapon_attack(struct block_list *src,
     if (hitrate < 1000000)
         hitrate = ((hitrate > 95) ? 95 : ((hitrate < 5) ? 5 : hitrate));
 
-    if (type == DamageType::NORMAL && MRAND(100) >= hitrate)
+    if (type == DamageType::NORMAL && !random_::chance({hitrate, 100}))
     {
         damage = damage2 = 0;
         dmg_lv = ATK::FLEE;
@@ -1278,7 +1248,7 @@ struct Damage battle_calc_mob_weapon_attack(struct block_list *src,
 
     // 完全回避の判定
     if (skill_num == SkillID::ZERO && skill_lv >= 0 && tsd != NULL
-        && MRAND(1000) < battle_get_flee2(target))
+        && random_::chance({battle_get_flee2(target), 1000}))
     {
         damage = 0;
         type = DamageType::FLEE2;
@@ -1288,7 +1258,7 @@ struct Damage battle_calc_mob_weapon_attack(struct block_list *src,
     if (battle_config.enemy_perfect_flee)
     {
         if (skill_num == SkillID::ZERO && skill_lv >= 0 && tmd != NULL
-            && MRAND(1000) < battle_get_flee2(target))
+            && random_::chance({battle_get_flee2(target), 1000}))
         {
             damage = 0;
             type = DamageType::FLEE2;
@@ -1359,7 +1329,6 @@ struct Damage battle_calc_pc_weapon_attack(struct block_list *src,
     int watk, watk_;
     bool da = false;
     int ac_flag = 0;
-    int idef_flag = 0, idef_flag_ = 0;
     int target_distance;
 
     nullpo_retr(wd, src);
@@ -1471,13 +1440,13 @@ struct Damage battle_calc_pc_weapon_attack(struct block_list *src,
         atkmin_ = atkmax_;
 
     if (sd->double_rate > 0 && skill_num == SkillID::ZERO && skill_lv >= 0)
-        da = MRAND(100) < sd->double_rate;
+        da = random_::chance({sd->double_rate, 100});
 
     // 過剰精錬ボーナス
     if (sd->overrefine > 0)
-        damage += MPRAND(1, sd->overrefine);
+        damage += random_::in(1, sd->overrefine);
     if (sd->overrefine_ > 0)
-        damage2 += MPRAND(1, sd->overrefine_);
+        damage2 += random_::in(1, sd->overrefine_);
 
     if (!da)
     {                           //ダブルアタックが発動していない
@@ -1497,8 +1466,10 @@ struct Damage battle_calc_pc_weapon_attack(struct block_list *src,
     if (tsd && tsd->critical_def)
         cri = cri * (100 - tsd->critical_def) / 100;
 
-    if (!da && skill_num == SkillID::ZERO && skill_lv >= 0 && //ダブルアタックが発動していない
-        (MRAND(1000)) < cri)   // 判定（スキルの場合は無視）
+    //ダブルアタックが発動していない
+    // 判定（スキルの場合は無視）
+    if (!da && skill_num == SkillID::ZERO && skill_lv >= 0
+        && random_::chance({cri, 1000}))
     {
         damage += atkmax;
         damage2 += atkmax_;
@@ -1516,11 +1487,11 @@ struct Damage battle_calc_pc_weapon_attack(struct block_list *src,
         int vitbonusmax;
 
         if (atkmax > atkmin)
-            damage += atkmin + MRAND((atkmax - atkmin + 1));
+            damage += random_::in(atkmin, atkmax);
         else
             damage += atkmin;
         if (atkmax_ > atkmin_)
-            damage2 += atkmin_ + MRAND((atkmax_ - atkmin_ + 1));
+            damage2 += random_::in(atkmin_, atkmax_);
         else
             damage2 += atkmin_;
         if (sd->atk_rate != 100)
@@ -1532,7 +1503,7 @@ struct Damage battle_calc_pc_weapon_attack(struct block_list *src,
         if (sd->state.arrow_atk)
         {
             if (sd->arrow_atk > 0)
-                damage += MRAND((sd->arrow_atk + 1));
+                damage += random_::in(0, sd->arrow_atk);
             hitrate += sd->arrow_hit;
         }
 
@@ -1604,42 +1575,20 @@ struct Damage battle_calc_pc_weapon_attack(struct block_list *src,
                 t_def = def2 * 8 / 10;
                 vitbonusmax = (t_vit / 20) * (t_vit / 20) - 1;
 
-                if (!idef_flag)
                 {
-                    if (battle_config.player_defense_type)
-                    {
-                        damage =
-                            damage -
-                            (def1 * battle_config.player_defense_type) -
-                            t_def -
-                            ((vitbonusmax <
-                              1) ? 0 : MRAND((vitbonusmax + 1)));
-                    }
-                    else
                     {
-                        damage =
-                            damage * (100 - def1) / 100 - t_def -
-                            ((vitbonusmax <
-                              1) ? 0 : MRAND((vitbonusmax + 1)));
+                        damage = damage * (100 - def1) / 100;
+                        damage -= t_def;
+                        if (vitbonusmax > 0)
+                            damage -= random_::in(0, vitbonusmax);
                     }
                 }
-                if (!idef_flag_)
                 {
-                    if (battle_config.player_defense_type)
-                    {
-                        damage2 =
-                            damage2 -
-                            (def1 * battle_config.player_defense_type) -
-                            t_def -
-                            ((vitbonusmax <
-                              1) ? 0 : MRAND((vitbonusmax + 1)));
-                    }
-                    else
                     {
-                        damage2 =
-                            damage2 * (100 - def1) / 100 - t_def -
-                            ((vitbonusmax <
-                              1) ? 0 : MRAND((vitbonusmax + 1)));
+                        damage2 = damage2 * (100 - def1) / 100;
+                        damage2 -= t_def;
+                        if (vitbonusmax > 0)
+                            damage2 -= random_::in(0, vitbonusmax);
                     }
                 }
             }
@@ -1664,13 +1613,13 @@ struct Damage battle_calc_pc_weapon_attack(struct block_list *src,
 
     if (sd->perfect_hit > 0)
     {
-        if (MRAND(100) < sd->perfect_hit)
+        if (random_::chance({sd->perfect_hit, 100}))
             hitrate = 1000000;
     }
 
     // 回避修正
     hitrate = (hitrate < 5) ? 5 : hitrate;
-    if (type == DamageType::NORMAL && MRAND(100) >= hitrate)
+    if (type == DamageType::NORMAL && !random_::chance({hitrate, 100}))
     {
         damage = damage2 = 0;
         dmg_lv = ATK::FLEE;
@@ -1735,7 +1684,7 @@ struct Damage battle_calc_pc_weapon_attack(struct block_list *src,
 
     // 完全回避の判定
     if (skill_num == SkillID::ZERO && skill_lv >= 0 && tsd != NULL && div_ < 255
-        && MRAND(1000) < battle_get_flee2(target))
+        && random_::chance({battle_get_flee2(target), 1000}))
     {
         damage = damage2 = 0;
         type = DamageType::FLEE2;
@@ -1746,7 +1695,7 @@ struct Damage battle_calc_pc_weapon_attack(struct block_list *src,
     if (battle_config.enemy_perfect_flee)
     {
         if (skill_num == SkillID::ZERO && skill_lv >= 0 && tmd != NULL && div_ < 255
-            && MRAND(1000) < battle_get_flee2(target))
+            && random_::chance({battle_get_flee2(target), 1000}))
         {
             damage = damage2 = 0;
             type = DamageType::FLEE2;
@@ -1818,39 +1767,6 @@ struct Damage battle_calc_weapon_attack(struct block_list *src,
     else if (src->type == BL::MOB)
         wd = battle_calc_mob_weapon_attack(src, target, skill_num, skill_lv, wflag);
 
-    if (battle_config.equipment_breaking && src->type == BL::PC
-        && (wd.damage > 0 || wd.damage2 > 0))
-    {
-        struct map_session_data *sd = (struct map_session_data *) src;
-        if (sd->status.weapon && sd->status.weapon != 11)
-        {
-            int breakrate = 1;
-            if (wd.type == DamageType::CRITICAL)
-                breakrate *= 2;
-            if (MRAND(10000) <
-                breakrate * battle_config.equipment_break_rate / 100
-                || breakrate >= 10000)
-            {
-                pc_breakweapon(sd);
-                memset(&wd, 0, sizeof(wd));
-            }
-        }
-    }
-
-    if (battle_config.equipment_breaking && target->type == BL::PC
-        && (wd.damage > 0 || wd.damage2 > 0))
-    {
-        int breakrate = 1;
-        if (wd.type == DamageType::CRITICAL)
-            breakrate *= 2;
-        if (MRAND(10000) <
-            breakrate * battle_config.equipment_break_rate / 100
-            || breakrate >= 10000)
-        {
-            pc_breakarmor((struct map_session_data *) target);
-        }
-    }
-
     return wd;
 }
 
@@ -1877,41 +1793,31 @@ struct Damage battle_calc_magic_attack(struct block_list *bl,
     matk2 = battle_get_matk2(bl);
     MobMode t_mode = battle_get_mode(target);
 
-#define MATK_FIX(a, b)          \
-{                               \
-    matk1 = matk1 * (a) / (b);  \
-    matk2 = matk2 * (a) / (b);  \
-}
-
     if (bl->type == BL::PC && (sd = (struct map_session_data *) bl))
     {
         sd->state.attack_type = BF::MAGIC;
         if (sd->matk_rate != 100)
-            MATK_FIX(sd->matk_rate, 100);
+        {
+            matk1 = matk1 * sd->matk_rate / 100;
+            matk2 = matk2 * sd->matk_rate / 100;
+        }
         sd->state.arrow_atk = 0;
     }
 
     BF aflag = BF::MAGIC | BF::LONG | BF::SKILL;
 
     if (normalmagic_flag)
-    {                           // 一般魔法ダメージ計算
-        int imdef_flag = 0;
+    {
+        // 一般魔法ダメージ計算
         if (matk1 > matk2)
-            damage = matk2 + MRAND((matk1 - matk2 + 1));
+            damage = random_::in(matk2, matk1);
         else
             damage = matk2;
 
-        if (!imdef_flag)
         {
-            if (battle_config.magic_defense_type)
             {
-                damage =
-                    damage - (mdef1 * battle_config.magic_defense_type) -
-                    mdef2;
-            }
-            else
-            {
-                damage = (damage * (100 - mdef1)) / 100 - mdef2;
+                damage = (damage * (100 - mdef1)) / 100;
+                damage -= mdef2;
             }
         }
 
@@ -2171,22 +2077,22 @@ ATK battle_weapon_attack(struct block_list *src, struct block_list *target,
             {
                 int hp = 0, sp = 0;
                 if (sd->hp_drain_rate && wd.damage > 0
-                    && MRAND(100) < sd->hp_drain_rate)
+                    && random_::chance({sd->hp_drain_rate, 100}))
                 {
                     hp += (wd.damage * sd->hp_drain_per) / 100;
                 }
                 if (sd->hp_drain_rate_ && wd.damage2 > 0
-                    && MRAND(100) < sd->hp_drain_rate_)
+                    && random_::chance({sd->hp_drain_rate_, 100}))
                 {
                     hp += (wd.damage2 * sd->hp_drain_per_) / 100;
                 }
                 if (sd->sp_drain_rate && wd.damage > 0
-                    && MRAND(100) < sd->sp_drain_rate)
+                    && random_::chance({sd->sp_drain_rate, 100}))
                 {
                     sp += (wd.damage * sd->sp_drain_per) / 100;
                 }
                 if (sd->sp_drain_rate_ && wd.damage2 > 0
-                    && MRAND(100) < sd->sp_drain_rate_)
+                    && random_::chance({sd->sp_drain_rate_, 100}))
                 {
                     sp += (wd.damage2 * sd->sp_drain_per_) / 100;
                 }
@@ -2412,11 +2318,7 @@ int battle_config_read(const char *cfgName)
         battle_config.item_first_get_time = 3000;
         battle_config.item_second_get_time = 1000;
         battle_config.item_third_get_time = 1000;
-        battle_config.mvp_item_first_get_time = 10000;
-        battle_config.mvp_item_second_get_time = 10000;
-        battle_config.mvp_item_third_get_time = 2000;
 
-        battle_config.drop_rate0item = 0;
         battle_config.base_exp_rate = 100;
         battle_config.job_exp_rate = 100;
         battle_config.pvp_exp = 1;
@@ -2427,9 +2329,6 @@ int battle_config_read(const char *cfgName)
         battle_config.zeny_penalty = 0;
         battle_config.restart_hp_rate = 0;
         battle_config.restart_sp_rate = 0;
-        battle_config.mvp_item_rate = 100;
-        battle_config.mvp_exp_rate = 100;
-        battle_config.mvp_hp_rate = 100;
         battle_config.monster_hp_rate = 100;
         battle_config.monster_max_aspd = 199;
         battle_config.atc_gmonly = 0;
@@ -2482,14 +2381,11 @@ int battle_config_read(const char *cfgName)
         battle_config.agi_penaly_type = 0;
         battle_config.agi_penaly_count = 3;
         battle_config.agi_penaly_num = 0;
-        battle_config.agi_penaly_count_lv = int(ATK::FLEE); // FIXME
+        battle_config.agi_penaly_count_lv = static_cast<int>(ATK::FLEE); // FIXME
         battle_config.vit_penaly_type = 0;
         battle_config.vit_penaly_count = 3;
         battle_config.vit_penaly_num = 0;
-        battle_config.vit_penaly_count_lv = int(ATK::DEF); // FIXME
-        battle_config.player_defense_type = 0;
-        battle_config.monster_defense_type = 0;
-        battle_config.magic_defense_type = 0;
+        battle_config.vit_penaly_count_lv = static_cast<int>(ATK::DEF); // FIXME
         battle_config.pc_skill_reiteration = 0;
         battle_config.monster_skill_reiteration = 0;
         battle_config.pc_skill_nofootset = 0;
@@ -2527,28 +2423,9 @@ int battle_config_read(const char *cfgName)
         battle_config.invite_request_check = 1;
         battle_config.skill_removetrap_type = 0;
         battle_config.disp_experience = 0;
-        battle_config.item_rate_common = 100;
-        battle_config.item_rate_equip = 100;
-        battle_config.item_rate_card = 100;
-        battle_config.item_rate_heal = 100; // Added by Valaris
-        battle_config.item_rate_use = 100;  // End
-        battle_config.item_drop_common_min = 1; // Added by TyrNemesis^
-        battle_config.item_drop_common_max = 10000;
-        battle_config.item_drop_equip_min = 1;
-        battle_config.item_drop_equip_max = 10000;
-        battle_config.item_drop_card_min = 1;
-        battle_config.item_drop_card_max = 10000;
-        battle_config.item_drop_mvp_min = 1;
-        battle_config.item_drop_mvp_max = 10000;    // End Addition
-        battle_config.item_drop_heal_min = 1;   // Added by Valaris
-        battle_config.item_drop_heal_max = 10000;
-        battle_config.item_drop_use_min = 1;
-        battle_config.item_drop_use_max = 10000;    // End
         battle_config.prevent_logout = 1;   // Added by RoVeRT
         battle_config.maximum_level = 255;  // Added by Valaris
         battle_config.drops_by_luk = 0; // [Valaris]
-        battle_config.equipment_breaking = 0;   // [Valaris]
-        battle_config.equipment_break_rate = 100;   // [Valaris]
         battle_config.pk_mode = 0;  // [Valaris]
         battle_config.multi_level_up = 0;   // [Valaris]
         battle_config.backstab_bow_penalty = 0; // Akaru
@@ -2623,11 +2500,6 @@ int battle_config_read(const char *cfgName)
             {"item_first_get_time", &battle_config.item_first_get_time},
             {"item_second_get_time", &battle_config.item_second_get_time},
             {"item_third_get_time", &battle_config.item_third_get_time},
-            {"mvp_item_first_get_time", &battle_config.mvp_item_first_get_time},
-            {"mvp_item_second_get_time", &battle_config.mvp_item_second_get_time},
-            {"mvp_item_third_get_time", &battle_config.mvp_item_third_get_time},
-            {"item_rate", &battle_config.item_rate},
-            {"drop_rate0item", &battle_config.drop_rate0item},
             {"base_exp_rate", &battle_config.base_exp_rate},
             {"job_exp_rate", &battle_config.job_exp_rate},
             {"pvp_exp", &battle_config.pvp_exp},
@@ -2638,9 +2510,6 @@ int battle_config_read(const char *cfgName)
             {"zeny_penalty", &battle_config.zeny_penalty},
             {"restart_hp_rate", &battle_config.restart_hp_rate},
             {"restart_sp_rate", &battle_config.restart_sp_rate},
-            {"mvp_hp_rate", &battle_config.mvp_hp_rate},
-            {"mvp_item_rate", &battle_config.mvp_item_rate},
-            {"mvp_exp_rate", &battle_config.mvp_exp_rate},
             {"monster_hp_rate", &battle_config.monster_hp_rate},
             {"monster_max_aspd", &battle_config.monster_max_aspd},
             {"atcommand_gm_only", &battle_config.atc_gmonly},
@@ -2700,9 +2569,6 @@ int battle_config_read(const char *cfgName)
             {"vit_penaly_count", &battle_config.vit_penaly_count},
             {"vit_penaly_num", &battle_config.vit_penaly_num},
             {"vit_penaly_count_lv", &battle_config.vit_penaly_count_lv},
-            {"player_defense_type", &battle_config.player_defense_type},
-            {"monster_defense_type", &battle_config.monster_defense_type},
-            {"magic_defense_type", &battle_config.magic_defense_type},
             {"player_skill_reiteration", &battle_config.pc_skill_reiteration},
             {"monster_skill_reiteration", &battle_config.monster_skill_reiteration},
             {"player_skill_nofootset", &battle_config.pc_skill_nofootset},
@@ -2740,26 +2606,11 @@ int battle_config_read(const char *cfgName)
             {"skill_removetrap_type", &battle_config.skill_removetrap_type},
             {"disp_experience", &battle_config.disp_experience},
             {"riding_weight", &battle_config.riding_weight},
-            {"item_rate_common", &battle_config.item_rate_common},   // Added by RoVeRT
-            {"item_rate_equip", &battle_config.item_rate_equip},
-            {"item_rate_card", &battle_config.item_rate_card},   // End Addition
-            {"item_rate_heal", &battle_config.item_rate_heal},   // Added by Valaris
-            {"item_rate_use", &battle_config.item_rate_use}, // End
-            {"item_drop_common_min", &battle_config.item_drop_common_min},   // Added by TyrNemesis^
-            {"item_drop_common_max", &battle_config.item_drop_common_max},
-            {"item_drop_equip_min", &battle_config.item_drop_equip_min},
-            {"item_drop_equip_max", &battle_config.item_drop_equip_max},
-            {"item_drop_card_min", &battle_config.item_drop_card_min},
-            {"item_drop_card_max", &battle_config.item_drop_card_max},
-            {"item_drop_mvp_min", &battle_config.item_drop_mvp_min},
-            {"item_drop_mvp_max", &battle_config.item_drop_mvp_max}, // End Addition
             {"prevent_logout", &battle_config.prevent_logout},   // Added by RoVeRT
             {"alchemist_summon_reward", &battle_config.alchemist_summon_reward}, // [Valaris]
             {"maximum_level", &battle_config.maximum_level}, // [Valaris]
             {"drops_by_luk", &battle_config.drops_by_luk},   // [Valaris]
             {"monsters_ignore_gm", &battle_config.monsters_ignore_gm},   // [Valaris]
-            {"equipment_breaking", &battle_config.equipment_breaking},   // [Valaris]
-            {"equipment_break_rate", &battle_config.equipment_break_rate},   // [Valaris]
             {"pk_mode", &battle_config.pk_mode}, // [Valaris]
             {"multi_level_up", &battle_config.multi_level_up},   // [Valaris]
             {"backstab_bow_penalty", &battle_config.backstab_bow_penalty},
@@ -2867,23 +2718,6 @@ int battle_config_read(const char *cfgName)
         if (battle_config.vit_penaly_count < 2)
             battle_config.vit_penaly_count = 2;
 
-        if (battle_config.item_drop_common_min < 1) // Added by TyrNemesis^
-            battle_config.item_drop_common_min = 1;
-        if (battle_config.item_drop_common_max > 10000)
-            battle_config.item_drop_common_max = 10000;
-        if (battle_config.item_drop_equip_min < 1)
-            battle_config.item_drop_equip_min = 1;
-        if (battle_config.item_drop_equip_max > 10000)
-            battle_config.item_drop_equip_max = 10000;
-        if (battle_config.item_drop_card_min < 1)
-            battle_config.item_drop_card_min = 1;
-        if (battle_config.item_drop_card_max > 10000)
-            battle_config.item_drop_card_max = 10000;
-        if (battle_config.item_drop_mvp_min < 1)
-            battle_config.item_drop_mvp_min = 1;
-        if (battle_config.item_drop_mvp_max > 10000)
-            battle_config.item_drop_mvp_max = 10000;    // End Addition
-
         if (battle_config.hack_info_GM_level < 0)   // added by [Yor]
             battle_config.hack_info_GM_level = 0;
         else if (battle_config.hack_info_GM_level > 100)
diff --git a/src/map/battle.hpp b/src/map/battle.hpp
index 263e3f6..6d9d8dd 100644
--- a/src/map/battle.hpp
+++ b/src/map/battle.hpp
@@ -74,7 +74,6 @@ Element battle_get_elem_type(struct block_list *bl)
 int battle_get_party_id(struct block_list *bl);
 Race battle_get_race(struct block_list *bl);
 MobMode battle_get_mode(struct block_list *bl);
-int battle_get_mexp(struct block_list *bl);
 int battle_get_stat(SP stat_id, struct block_list *bl);
 
 eptr<struct status_change, StatusChange> battle_get_sc_data(struct block_list *bl);
@@ -112,11 +111,7 @@ extern struct Battle_Config
     int item_first_get_time;
     int item_second_get_time;
     int item_third_get_time;
-    int mvp_item_first_get_time;
-    int mvp_item_second_get_time;
-    int mvp_item_third_get_time;
-    int item_rate, base_exp_rate, job_exp_rate;    // removed item rate, depreciated
-    int drop_rate0item;
+    int base_exp_rate, job_exp_rate;
     int death_penalty_type;
     int death_penalty_base, death_penalty_job;
     int pvp_exp;               // [MouseJstr]
@@ -124,8 +119,6 @@ extern struct Battle_Config
     int zeny_penalty;
     int restart_hp_rate;
     int restart_sp_rate;
-    int mvp_item_rate, mvp_exp_rate;
-    int mvp_hp_rate;
     int monster_hp_rate;
     int monster_max_aspd;
     int atc_gmonly;
@@ -182,9 +175,6 @@ extern struct Battle_Config
     int vit_penaly_type;
     int vit_penaly_count;
     int vit_penaly_num;
-    int player_defense_type;
-    int monster_defense_type;
-    int magic_defense_type;
     int pc_skill_reiteration;
     int monster_skill_reiteration;
     int pc_skill_nofootset;
@@ -212,13 +202,6 @@ extern struct Battle_Config
     int mob_attack_attr_none;
     int mob_ghostring_fix;
     int pc_attack_attr_none;
-    int item_rate_common, item_rate_card, item_rate_equip, item_rate_heal, item_rate_use;  // Added by RoVeRT, Additional Heal and Usable item rate by Val
-    int item_drop_common_min, item_drop_common_max;    // Added by TyrNemesis^
-    int item_drop_card_min, item_drop_card_max;
-    int item_drop_equip_min, item_drop_equip_max;
-    int item_drop_mvp_min, item_drop_mvp_max;  // End Addition
-    int item_drop_heal_min, item_drop_heal_max;    // Added by Valatris
-    int item_drop_use_min, item_drop_use_max;  //End
 
     int prevent_logout;        // Added by RoVeRT
 
@@ -226,8 +209,6 @@ extern struct Battle_Config
     int maximum_level;
     int drops_by_luk;
     int monsters_ignore_gm;
-    int equipment_breaking;
-    int equipment_break_rate;
     int multi_level_up;
     int pk_mode;
     int show_mob_hp;           // end additions [Valaris]
diff --git a/src/map/clif.cpp b/src/map/clif.cpp
index b0fef3a..2da8a14 100644
--- a/src/map/clif.cpp
+++ b/src/map/clif.cpp
@@ -8,7 +8,7 @@
 
 #include "../common/cxxstdio.hpp"
 #include "../common/md5calc.hpp"
-#include "../common/mt_rand.hpp"
+#include "../common/random.hpp"
 #include "../common/nullpo.hpp"
 #include "../common/socket.hpp"
 #include "../common/timer.hpp"
diff --git a/src/map/itemdb.cpp b/src/map/itemdb.cpp
index 06b2873..9c6d4e6 100644
--- a/src/map/itemdb.cpp
+++ b/src/map/itemdb.cpp
@@ -5,7 +5,7 @@
 
 #include "../common/cxxstdio.hpp"
 #include "../common/db.hpp"
-#include "../common/mt_rand.hpp"
+#include "../common/random.hpp"
 #include "../common/nullpo.hpp"
 #include "../common/socket.hpp"
 
@@ -20,17 +20,6 @@ constexpr int MAX_RANDITEM = 2000;
 static
 struct dbt *item_db;
 
-static
-struct random_item_data blue_box[MAX_RANDITEM],
-    violet_box[MAX_RANDITEM], card_album[MAX_RANDITEM],
-    gift_box[MAX_RANDITEM], scroll[MAX_RANDITEM];
-static
-int blue_box_count = 0, violet_box_count = 0, card_album_count =
-    0, gift_box_count = 0, scroll_count = 0;
-static
-int blue_box_default = 0, violet_box_default = 0, card_album_default =
-    0, gift_box_default = 0, scroll_default = 0;
-
 // Function declarations
 
 static
@@ -38,8 +27,6 @@ void itemdb_read(void);
 static
 int itemdb_readdb(void);
 static
-int itemdb_read_randomitem(void);
-static
 int itemdb_read_itemavail(void);
 static
 int itemdb_read_noequip(void);
@@ -69,56 +56,6 @@ struct item_data *itemdb_searchname(const char *str)
 }
 
 /*==========================================
- * 箱系アイテム検索
- *------------------------------------------
- */
-int itemdb_searchrandomid(int flags)
-{
-    int nameid = 0, i, index, count;
-    struct random_item_data *list = NULL;
-
-    struct
-    {
-        int nameid, count;
-        struct random_item_data *list;
-    } data[] =
-    {
-        {
-        0, 0, NULL},
-        {
-        blue_box_default, blue_box_count, blue_box},
-        {
-        violet_box_default, violet_box_count, violet_box},
-        {
-        card_album_default, card_album_count, card_album},
-        {
-        gift_box_default, gift_box_count, gift_box},
-        {
-    scroll_default, scroll_count, scroll},};
-
-    if (flags >= 1 && flags <= 5)
-    {
-        nameid = data[flags].nameid;
-        count = data[flags].count;
-        list = data[flags].list;
-
-        if (count > 0)
-        {
-            for (i = 0; i < 1000; i++)
-            {
-                index = MRAND(count);
-                if (MRAND(1000000) < list[index].per)
-                {
-                    nameid = list[index].nameid;
-                    break;
-                }
-            }
-        }
-    }
-    return nameid;
-}
-
-/*==========================================
  * DBの存在確認
  *------------------------------------------
  */
@@ -323,98 +260,6 @@ int itemdb_readdb(void)
 // Removed item_value_db, don't re-add!
 
 /*==========================================
- * ランダムアイテム出現データの読み込み
- *------------------------------------------
- */
-static
-int itemdb_read_randomitem(void)
-{
-    FILE *fp;
-    char line[1024];
-    int ln = 0;
-    int nameid, i, j;
-    char *str[10], *p;
-
-    const struct
-    {
-        char filename[64];
-        struct random_item_data *pdata;
-        int *pcount, *pdefault;
-    } data[] =
-    {
-        {
-        "db/item_bluebox.txt", blue_box, &blue_box_count,
-                &blue_box_default},
-        {
-        "db/item_violetbox.txt", violet_box, &violet_box_count,
-                &violet_box_default},
-        {
-        "db/item_cardalbum.txt", card_album, &card_album_count,
-                &card_album_default},
-        {
-        "db/item_giftbox.txt", gift_box, &gift_box_count,
-                &gift_box_default},
-        {
-    "db/item_scroll.txt", scroll, &scroll_count, &scroll_default},};
-
-    for (i = 0; i < sizeof(data) / sizeof(data[0]); i++)
-    {
-        struct random_item_data *pd = data[i].pdata;
-        int *pc = data[i].pcount;
-        int *pdefault = data[i].pdefault;
-        const char *fn = data[i].filename;
-
-        *pdefault = 0;
-        if ((fp = fopen_(fn, "r")) == NULL)
-        {
-            PRINTF("can't read %s\n", fn);
-            continue;
-        }
-
-        while (fgets(line, 1020, fp))
-        {
-            if (line[0] == '/' && line[1] == '/')
-                continue;
-            memset(str, 0, sizeof(str));
-            for (j = 0, p = line; j < 3 && p; j++)
-            {
-                str[j] = p;
-                p = strchr(p, ',');
-                if (p)
-                    *p++ = 0;
-            }
-
-            if (str[0] == NULL)
-                continue;
-
-            nameid = atoi(str[0]);
-            if (nameid < 0 || nameid >= 20000)
-                continue;
-            if (nameid == 0)
-            {
-                if (str[2])
-                    *pdefault = atoi(str[2]);
-                continue;
-            }
-
-            if (str[2])
-            {
-                pd[*pc].nameid = nameid;
-                pd[(*pc)++].per = atoi(str[2]);
-            }
-
-            if (ln >= MAX_RANDITEM)
-                break;
-            ln++;
-        }
-        fclose_(fp);
-        PRINTF("read %s done (count=%d)\n", fn, *pc);
-    }
-
-    return 0;
-}
-
-/*==========================================
  * アイテム使用可能フラグのオーバーライド
  *------------------------------------------
  */
@@ -585,7 +430,6 @@ static
 void itemdb_read(void)
 {
     itemdb_readdb();
-    itemdb_read_randomitem();
     itemdb_read_itemavail();
     itemdb_read_noequip();
 }
diff --git a/src/map/itemdb.hpp b/src/map/itemdb.hpp
index 688fac1..3b808a8 100644
--- a/src/map/itemdb.hpp
+++ b/src/map/itemdb.hpp
@@ -87,8 +87,6 @@ int itemdb_viewid(int n)
     return itemdb_search(n)->view_id;
 }
 
-int itemdb_searchrandomid(int flags);
-
 inline
 int itemdb_value_sell(int n)
 {
diff --git a/src/map/magic-expr.cpp b/src/map/magic-expr.cpp
index 65dafe4..ea853a1 100644
--- a/src/map/magic-expr.cpp
+++ b/src/map/magic-expr.cpp
@@ -5,7 +5,7 @@
 #include <cmath>
 
 #include "../common/cxxstdio.hpp"
-#include "../common/mt_rand.hpp"
+#include "../common/random.hpp"
 
 #include "battle.hpp"
 #include "npc.hpp"
@@ -709,7 +709,7 @@ int fun_random(env_t *, int, val_t *result, val_t *args)
         RESULTINT = 0;
         return 0;
     }
-    RESULTINT = MRAND(delta);
+    RESULTINT = random_::to(delta);
 
     if (ARGINT(0) < 0)
         RESULTINT = -RESULTINT;
@@ -720,9 +720,9 @@ static
 int fun_random_dir(env_t *, int, val_t *result, val_t *args)
 {
     if (ARGINT(0))
-        RESULTDIR = DIR(MRAND(8));
+        RESULTDIR = random_::choice({DIR::S, DIR::SW, DIR::W, DIR::NW, DIR::N, DIR::NE, DIR::E, DIR::SE});
     else
-        RESULTDIR = DIR(MRAND(4) * 2);
+        RESULTDIR = random_::choice({DIR::S, DIR::W, DIR::N, DIR::E});
     return 0;
 }
 
@@ -945,8 +945,7 @@ void magic_random_location(location_t *dest, area_t *area)
     {
         case AREA::UNION:
         {
-            int rv = MRAND(area->size);
-            if (rv < area->a.a_union[0]->size)
+            if (random_::chance({area->a.a_union[0]->size, area->size}))
                 magic_random_location(dest, area->a.a_union[0]);
             else
                 magic_random_location(dest, area->a.a_union[1]);
@@ -966,39 +965,13 @@ void magic_random_location(location_t *dest, area_t *area)
             if (h <= 1)
                 h = 1;
 
-            x += MRAND(w);
-            y += MRAND(h);
-
-            if (!map_is_solid(m, x, y))
-            {
-                int start_x = x;
-                int start_y = y;
-                int i;
-                DIR initial_dir = DIR(MRAND(8));
-                DIR dir = initial_dir;
-
-                /* try all directions, up to a distance to 10, for a free slot */
-                do
-                {
-                    x = start_x;
-                    y = start_y;
-
-                    for (i = 0; i < 10 && map_is_solid(m, x, y); i++)
-                    {
-                        x += dirx[dir];
-                        y += diry[dir];
-                    }
-
-                    dir = DIR((uint8_t(dir) + 1) % 8);
-                }
-                while (map_is_solid(m, x, y) && dir != initial_dir);
-
-            }
-            /* We've tried our best.  If the map is still solid, the engine will automatically randomise the target location if we try to warp. */
+            // This is not exactly the same as the old logic,
+            // but it's better.
+            auto pair = map_randfreecell(m, x, y, w, h);
 
             dest->m = m;
-            dest->x = x;
-            dest->y = y;
+            dest->x = pair.first;
+            dest->y = pair.second;
             break;
         }
 
diff --git a/src/map/magic-stmt.cpp b/src/map/magic-stmt.cpp
index fdb95fc..c729cfd 100644
--- a/src/map/magic-stmt.cpp
+++ b/src/map/magic-stmt.cpp
@@ -1,7 +1,7 @@
 #include <cassert>
 
 #include "../common/cxxstdio.hpp"
-#include "../common/mt_rand.hpp"
+#include "../common/random2.hpp"
 #include "../common/timer.hpp"
 
 #include "magic-expr.hpp"
@@ -1235,36 +1235,18 @@ effect_t *run_foreach(invocation_t *invocation, effect_t *foreach,
         cont_activation_record_t *ar =
             add_stack_entry(invocation, CONT_STACK::FOREACH, return_location);
         int entities_allocd = 64;
-        int *entities_collect;
         int *entities;
-        int *shuffle_board;
         int entities_nr = 0;
-        int i;
 
         if (!ar)
             return return_location;
 
-        CREATE(entities_collect, int, entities_allocd);
-
+        CREATE(entities, int, entities_allocd);
         find_entities_in_area(area.v.v_area, &entities_allocd, &entities_nr,
-                               &entities_collect, filter);
-
-        /* Now shuffle */
-        CREATE(shuffle_board, int, entities_nr);
-        CREATE(entities, int, entities_nr);
-        for (i = 0; i < entities_nr; i++)
-            shuffle_board[i] = i;
-
-        for (i = entities_nr - 1; i >= 0; i--)
-        {
-            int random_index = MRAND(i + 1);
-            entities[i] = entities_collect[shuffle_board[random_index]];
-            shuffle_board[random_index] = shuffle_board[i]; // thus, we are guaranteed only to use unused indices
-        }
-
-        free(entities_collect);
-        free(shuffle_board);
-        /* Done shuffling */
+                &entities, filter);
+        RECREATE(entities, int, entities_nr);
+        // iterator_pair will go away when this gets properly containerized.
+        random_::shuffle(iterator_pair(entities, entities + entities_nr));
 
         ar->c.c_foreach.id = id;
         ar->c.c_foreach.body = body;
diff --git a/src/map/map.cpp b/src/map/map.cpp
index 7e2bf13..6ed7662 100644
--- a/src/map/map.cpp
+++ b/src/map/map.cpp
@@ -13,7 +13,7 @@
 #include "../common/cxxstdio.hpp"
 #include "../common/db.hpp"
 #include "../common/grfio.hpp"
-#include "../common/mt_rand.hpp"
+#include "../common/random2.hpp"
 #include "../common/nullpo.hpp"
 #include "../common/socket.hpp"
 #include "../common/timer.hpp"
@@ -768,56 +768,24 @@ void map_clearflooritem_timer(TimerData *tid, tick_t, int id)
     map_delobject(fitem->bl.id, BL::ITEM);
 }
 
-/*==========================================
- * (m,x,y)の周囲rangeマス内の空き(=侵入可能)cellの
- * 内から適当なマス目の座標をx+(y<<16)で返す
- *
- * 現状range=1でアイテムドロップ用途のみ
- *------------------------------------------
- */
-static
-int map_searchrandfreecell(int m, int x, int y, int range)
+std::pair<uint16_t, uint16_t> map_randfreecell(int m, uint16_t x, uint16_t y, uint16_t w, uint16_t h)
 {
-    int free_cell, i, j, c;
-
-    for (free_cell = 0, i = -range; i <= range; i++)
-    {
-        if (i + y < 0 || i + y >= map[m].ys)
-            continue;
-        for (j = -range; j <= range; j++)
-        {
-            if (j + x < 0 || j + x >= map[m].xs)
-                continue;
-            if ((c = read_gat(m, j + x, i + y)) == 1 || c == 5)
-                continue;
-            free_cell++;
-        }
-    }
-    if (free_cell == 0)
-        return -1;
-    free_cell = MRAND(free_cell);
-    for (i = -range; i <= range; i++)
+    for (int itr : random_::iterator(w * h))
     {
-        if (i + y < 0 || i + y >= map[m].ys)
-            continue;
-        for (j = -range; j <= range; j++)
-        {
-            if (j + x < 0 || j + x >= map[m].xs)
-                continue;
-            if ((c = read_gat(m, j + x, i + y)) == 1 || c == 5)
-                continue;
-            if (free_cell == 0)
-            {
-                x += j;
-                y += i;
-                i = range + 1;
-                break;
-            }
-            free_cell--;
-        }
+        int dx = itr % w;
+        int dy = itr / w;
+        if (read_gat(m, x + dx, y + dy) == 1)
+            return {static_cast<uint16_t>(x + dx), static_cast<uint16_t>(y + dy)};
     }
+    return {static_cast<uint16_t>(0), static_cast<uint16_t>(0)};
+}
 
-    return x + (y << 16);
+/// Return a randomly selected passable cell within a given range.
+static
+std::pair<uint16_t, uint16_t> map_searchrandfreecell(int m, int x, int y, int range)
+{
+    int whole_range = 2 * range + 1;
+    return map_randfreecell(m, x - range, y - range, whole_range, whole_range);
 }
 
 /*==========================================
@@ -831,21 +799,19 @@ int map_addflooritem_any(struct item *item_data, int amount,
         struct map_session_data **owners, interval_t *owner_protection,
         interval_t lifetime, int dispersal)
 {
-    int xy, r;
     struct flooritem_data *fitem = NULL;
 
     nullpo_ret(item_data);
-
-    if ((xy = map_searchrandfreecell(m, x, y, dispersal)) < 0)
+    auto xy = map_searchrandfreecell(m, x, y, dispersal);
+    if (xy.first == 0 && xy.second == 0)
         return 0;
-    r = mt_random();
 
     CREATE(fitem, struct flooritem_data, 1);
     fitem->bl.type = BL::ITEM;
     fitem->bl.prev = fitem->bl.next = NULL;
     fitem->bl.m = m;
-    fitem->bl.x = xy & 0xffff;
-    fitem->bl.y = (xy >> 16) & 0xffff;
+    fitem->bl.x = xy.first;
+    fitem->bl.y = xy.second;
     fitem->first_get_id = 0;
     fitem->first_get_tick = tick_t();
     fitem->second_get_id = 0;
@@ -876,8 +842,13 @@ int map_addflooritem_any(struct item *item_data, int amount,
 
     memcpy(&fitem->item_data, item_data, sizeof(*item_data));
     fitem->item_data.amount = amount;
-    fitem->subx = (r & 3) * 3 + 3;
-    fitem->suby = ((r >> 2) & 3) * 3 + 3;
+    // TODO - talk to 4144 about maybe removing this.
+    // It has no effect on the server itself, it is visual only.
+    // If it is desirable to prevent items from visibly stacking
+    // on the ground, that can be done with client-side randomness.
+    // Currently, it yields the numbers {3 6 9 12}.
+    fitem->subx = random_::in(1, 4) * 3;
+    fitem->suby = random_::in(1, 4) * 3;
     fitem->cleartimer = add_timer(gettick() + lifetime,
             std::bind(map_clearflooritem_timer, ph::_1, ph::_2,
                 fitem->bl.id));
@@ -892,18 +863,11 @@ int map_addflooritem(struct item *item_data, int amount,
         int m, int x, int y,
         struct map_session_data *first_sd,
         struct map_session_data *second_sd,
-        struct map_session_data *third_sd, bool type)
+        struct map_session_data *third_sd)
 {
     struct map_session_data *owners[3] = { first_sd, second_sd, third_sd };
     interval_t owner_protection[3];
 
-    if (type)
-    {
-        owner_protection[0] = static_cast<interval_t>(battle_config.mvp_item_first_get_time);
-        owner_protection[1] = owner_protection[0] + static_cast<interval_t>(battle_config.mvp_item_second_get_time);
-        owner_protection[2] = owner_protection[1] + static_cast<interval_t>(battle_config.mvp_item_third_get_time);
-    }
-    else
     {
         owner_protection[0] = static_cast<interval_t>(battle_config.item_first_get_time);
         owner_protection[1] = owner_protection[0] + static_cast<interval_t>(battle_config.item_second_get_time);
diff --git a/src/map/map.hpp b/src/map/map.hpp
index 2af7ec8..72ded63 100644
--- a/src/map/map.hpp
+++ b/src/map/map.hpp
@@ -419,7 +419,6 @@ struct map_data
         unsigned nopenalty:1;
         unsigned pvp:1;
         unsigned pvp_noparty:1;
-        unsigned pvp_nightmaredrop:1;
         unsigned pvp_nocalcrank:1;
         unsigned nozenypenalty:1;
         unsigned notrade:1;
@@ -557,7 +556,7 @@ int map_addflooritem_any(struct item *, int amount, int m, int x, int y,
         interval_t lifetime, int dispersal);
 int map_addflooritem(struct item *, int, int, int, int,
         struct map_session_data *, struct map_session_data *,
-        struct map_session_data *, bool);
+        struct map_session_data *);
 
 // キャラid＝＞キャラ名 変換関連
 void map_addchariddb(int charid, const char *name);
@@ -594,6 +593,7 @@ DIR map_calc_dir(struct block_list *src, int x, int y);
 
 // path.cより
 int path_search(struct walkpath_data *, int, int, int, int, int, int);
-int path_blownpos(int m, int x0, int y0, int dx, int dy, int count);
+
+std::pair<uint16_t, uint16_t> map_randfreecell(int m, uint16_t x, uint16_t y, uint16_t w, uint16_t h);
 
 #endif // MAP_HPP
diff --git a/src/map/mob.cpp b/src/map/mob.cpp
index 20bf1ec..80671c2 100644
--- a/src/map/mob.cpp
+++ b/src/map/mob.cpp
@@ -1,3 +1,4 @@
+
 #include "mob.hpp"
 
 #include <cassert>
@@ -8,7 +9,7 @@
 #include <algorithm>
 
 #include "../common/cxxstdio.hpp"
-#include "../common/mt_rand.hpp"
+#include "../common/random.hpp"
 #include "../common/nullpo.hpp"
 #include "../common/socket.hpp"
 #include "../common/timer.hpp"
@@ -27,9 +28,9 @@
 constexpr interval_t MIN_MOBTHINKTIME = std::chrono::milliseconds(100);
 
 // Move probability in the negligent mode MOB (rate of 1000 minute)
-constexpr int MOB_LAZYMOVEPERC = 50;
+constexpr random_::Fraction MOB_LAZYMOVEPERC {50, 1000};
 // Warp probability in the negligent mode MOB (rate of 1000 minute)
-constexpr int MOB_LAZYWARPPERC = 20;
+constexpr random_::Fraction MOB_LAZYWARPPERC {20, 1000};
 
 struct mob_db mob_db[2001];
 
@@ -326,19 +327,33 @@ void mob_init(struct mob_data *md)
 
     for (i = 0; i < mutations_nr; i++)
     {
-        mob_stat stat_nr = mob_stat(MRAND(unsigned(mob_stat::LAST)));
-        int strength;
-
-        // double chance to modify hp
-        if (stat_nr == mob_stat::XP_BONUS)
-            stat_nr = mob_stat::MAX_HP;
-
-        strength =
-            ((MRAND((mutation_power >> 1)) +
-              (MRAND((mutation_power >> 1))) +
-              2) * mutation_scale[stat_nr]) / 100;
-
-        strength = MRAND(2) ? strength : -strength;
+        mob_stat stat_nr = random_::choice({
+            mob_stat::LV,
+            mob_stat::MAX_HP,
+            mob_stat::STR,
+            mob_stat::AGI,
+            mob_stat::VIT,
+            mob_stat::INT,
+            mob_stat::DEX,
+            mob_stat::LUK,
+            mob_stat::ATK1,
+            mob_stat::ATK2,
+            mob_stat::ADELAY,
+            mob_stat::DEF,
+            mob_stat::MDEF,
+            mob_stat::SPEED,
+            // double chance to modify hp
+            mob_stat::MAX_HP,
+        });
+        // TODO: if I don't remove this entirely, look into
+        // normal distributions.
+        int strength = (random_::to(mutation_power / 2)
+                + random_::to(mutation_power / 2)
+                + 2)
+            * mutation_scale[stat_nr] / 100;
+
+        if (random_::coin())
+            strength = -strength;
 
         if (strength < -240)
             strength = -240;    /* Don't go too close to zero */
@@ -356,10 +371,7 @@ int mob_once_spawn(struct map_session_data *sd, const char *mapname,
                     const char *event)
 {
     struct mob_data *md = NULL;
-    int m, count, lv = 255, r = mob_class;
-
-    if (sd)
-        lv = sd->status.base_level;
+    int m, count, r = mob_class;
 
     if (sd && strcmp(mapname, "this") == 0)
         m = sd->bl.m;
@@ -369,35 +381,6 @@ int mob_once_spawn(struct map_session_data *sd, const char *mapname,
     if (m < 0 || amount <= 0 || (mob_class >= 0 && mob_class <= 1000) || mob_class > 2000)  // 値が異常なら召喚を止める
         return 0;
 
-    if (mob_class < 0)
-    {                           // ランダムに召喚
-        int i = 0;
-        int j = -mob_class - 1;
-        int k;
-        if (j >= 0 && j < MAX_RANDOMMONSTER)
-        {
-            do
-            {
-                mob_class = MPRAND(1001, 1000);
-                k = MRAND(1000000);
-            }
-            while ((mob_db[mob_class].max_hp <= 0
-                    || mob_db[mob_class].summonper[j] <= k
-                    || (lv < mob_db[mob_class].lv
-                        && battle_config.random_monster_checklv == 1))
-                   && (i++) < 2000);
-            if (i >= 2000)
-            {
-                mob_class = mob_db[0].summonper[j];
-            }
-        }
-        else
-        {
-            return 0;
-        }
-//      if(battle_config.etc_log==1)
-//          PRINTF("mobmob_class=%d try=%d\n",mob_class,i);
-    }
     if (sd)
     {
         if (x <= 0)
@@ -472,8 +455,8 @@ int mob_once_spawn_area(struct map_session_data *sd, const char *mapname,
         int j = 0;
         do
         {
-            x = MPRAND(x0, (x1 - x0 + 1));
-            y = MPRAND(y0, (y1 - y0 + 1));
+            x = random_::in(x0, x1);
+            y = random_::in(y0, y1);
         }
         while (((c = map_getcell(m, x, y)) == 1 || c == 5) && (++j) < max);
         if (j >= max)
@@ -493,65 +476,6 @@ int mob_once_spawn_area(struct map_session_data *sd, const char *mapname,
     return id;
 }
 
-/*==========================================
- * Summoning Guardians [Valaris]
- *------------------------------------------
- */
-int mob_spawn_guardian(struct map_session_data *sd, const char *mapname,
-                        int x, int y, const char *mobname, int mob_class,
-                        int amount, const char *event, int)
-{
-    struct mob_data *md = NULL;
-    int m, count = 1;
-
-    if (sd && strcmp(mapname, "this") == 0)
-        m = sd->bl.m;
-    else
-        m = map_mapname2mapid(mapname);
-
-    if (m < 0 || amount <= 0 || (mob_class >= 0 && mob_class <= 1000) || mob_class > 2000)  // 値が異常なら召喚を止める
-        return 0;
-
-    if (mob_class < 0)
-        return 0;
-
-    if (sd)
-    {
-        if (x <= 0)
-            x = sd->bl.x;
-        if (y <= 0)
-            y = sd->bl.y;
-    }
-
-    else if (x <= 0 || y <= 0)
-        PRINTF("mob_spawn_guardian: ??\n");
-
-    for (count = 0; count < amount; count++)
-    {
-        CREATE(md, struct mob_data, 1);
-
-        mob_spawn_dataset(md, mobname, mob_class);
-        md->bl.m = m;
-        md->bl.x = x;
-        md->bl.y = y;
-        md->m = m;
-        md->x0 = x;
-        md->y0 = y;
-        md->xs = 0;
-        md->ys = 0;
-        md->spawndelay1 = static_cast<interval_t>(-1);   // Only once is a flag.
-        md->spawndelay2 = static_cast<interval_t>(-1);   // Only once is a flag.
-
-        memcpy(md->npc_event, event, sizeof(md->npc_event));
-
-        md->bl.type = BL::MOB;
-        map_addiddb(&md->bl);
-        mob_spawn(md->bl.id);
-    }
-
-    return (amount > 0) ? md->bl.id : 0;
-}
-
 // TODO: deprecate these
 int mob_get_sex(int mob_class)
 {
@@ -1162,13 +1086,15 @@ int mob_spawn(int id)
         {
             if (md->x0 == 0 && md->y0 == 0)
             {
-                x = MPRAND(1, (map[md->bl.m].xs - 2));
-                y = MPRAND(1, (map[md->bl.m].ys - 2));
+                x = random_::in(1, map[md->bl.m].xs - 2);
+                y = random_::in(1, map[md->bl.m].ys - 2);
             }
             else
             {
-                x = MPRAND(md->x0, (md->xs + 1)) - md->xs / 2;
-                y = MPRAND(md->y0, (md->ys + 1)) - md->ys / 2;
+                // TODO: move this logic earlier - possibly all the way
+                // into the data files
+                x = md->x0 - md->xs / 2 + random_::in(0, md->xs);
+                y = md->y0 - md->ys / 2 + random_::in(0, md->ys);
             }
             i++;
         }
@@ -1207,7 +1133,7 @@ int mob_spawn(int id)
     md->state.skillstate = MobSkillState::MSS_IDLE;
     md->timer = nullptr;
     md->last_thinktime = tick;
-    md->next_walktime = tick + std::chrono::seconds(5) + std::chrono::milliseconds(MRAND(50));
+    md->next_walktime = tick + std::chrono::seconds(5) + std::chrono::milliseconds(random_::to(50));
     md->attackabletime = tick;
     md->canmove_tick = tick;
 
@@ -1412,7 +1338,8 @@ int mob_target(struct mob_data *md, struct block_list *bl, int dist)
     }
     // Nothing will be carried out if there is no mind of changing TAGE by TAGE ending.
     if ((md->target_id > 0 && md->state.attackable)
-        && (!bool(mode & MobMode::AGGRESSIVE) || MRAND(100) > 25))
+        && (!bool(mode & MobMode::AGGRESSIVE)
+            || !random_::chance({25 + 1, 100})))
         return 0;
 
     // Coercion is exerted if it is MVPMOB.
@@ -1494,10 +1421,13 @@ void mob_ai_sub_hard_activesearch(struct block_list *bl,
                 || (!tsd->state.gangsterparadise
                     || race == Race::_insect
                     || race == Race::_demon))
-            {                   // 妨害がないか判定
-                if (mob_can_reach(smd, bl, 12) &&  // 到達可能性判定
-                    MRAND(1000) < 1000 / (++(*pcc)))
-                {               // 範囲内PCで等確率にする
+            {
+                // 妨害がないか判定
+                // 到達可能性判定
+                if (mob_can_reach(smd, bl, 12)
+                    && random_::chance({1, ++*pcc}))
+                {
+                    // 範囲内PCで等確率にする
                     smd->target_id = tsd->bl.id;
                     smd->state.attackable = true;
                     smd->min_chase = 13;
@@ -1510,9 +1440,11 @@ void mob_ai_sub_hard_activesearch(struct block_list *bl,
                  (dist =
                   distance(smd->bl.x, smd->bl.y, tmd->bl.x, tmd->bl.y)) < 9)
         {
-            if (mob_can_reach(smd, bl, 12) &&  // 到達可能性判定
-                MRAND(1000) < 1000 / (++(*pcc)))
-            {                   // 範囲内で等確率にする
+            // 到達可能性判定
+            if (mob_can_reach(smd, bl, 12)
+                && random_::chance({1, ++*pcc}))
+            {
+                // 範囲内で等確率にする
                 smd->target_id = bl->id;
                 smd->state.attackable = true;
                 smd->min_chase = 13;
@@ -1551,9 +1483,11 @@ void mob_ai_sub_hard_lootsearch(struct block_list *bl, struct mob_data *md, int
         if (bl->m == md->bl.m
             && (dist = distance(md->bl.x, md->bl.y, bl->x, bl->y)) < 9)
         {
-            if (mob_can_reach(md, bl, 12) &&   // Reachability judging
-                MRAND(1000) < 1000 / (++(*itc)))
-            {                   // It is made a probability, such as within the limits PC.
+            // Reachability judging
+            if (mob_can_reach(md, bl, 12)
+                && random_::chance({1, ++*itc}))
+            {
+                // It is made a probability, such as within the limits PC.
                 md->target_id = bl->id;
                 md->state.attackable = false;
                 md->min_chase = 13;
@@ -1653,18 +1587,18 @@ int mob_ai_sub_hard_slavemob(struct mob_data *md, tick_t tick)
                     dx = mmd->bl.x - md->bl.x;
                     dy = mmd->bl.y - md->bl.y;
                     if (dx < 0)
-                        dx += (MPRAND(1, ((dx < -3) ? 3 : -dx)));
+                        dx += random_::in(1, std::min(3, -dx));
                     else if (dx > 0)
-                        dx -= (MPRAND(1, ((dx > 3) ? 3 : dx)));
+                        dx -= random_::in(1, std::min(3, dx));
                     if (dy < 0)
-                        dy += (MPRAND(1, ((dy < -3) ? 3 : -dy)));
+                        dy += random_::in(1, std::min(3, -dy));
                     else if (dy > 0)
-                        dy -= (MPRAND(1, ((dy > 3) ? 3 : dy)));
+                        dy -= random_::in(1, std::min(3, dy));
                 }
                 else
                 {
-                    dx = mmd->bl.x - md->bl.x + MRAND(7) - 3;
-                    dy = mmd->bl.y - md->bl.y + MRAND(7) - 3;
+                    dx = mmd->bl.x - md->bl.x + random_::in(-3, 3);
+                    dy = mmd->bl.y - md->bl.y + random_::in(-3, 3);
                 }
 
                 ret = mob_walktoxy(md, md->bl.x + dx, md->bl.y + dy, 0);
@@ -1676,12 +1610,14 @@ int mob_ai_sub_hard_slavemob(struct mob_data *md, tick_t tick)
         {
             do
             {
-                dx = MRAND(9) - 5;
-                dy = MRAND(9) - 5;
+                // changed to do what it was obviously supposed to do,
+                // instead of what it was doing ...
+                dx = random_::in(-4, 4);
+                dy = random_::in(-4, 4);
                 if (dx == 0 && dy == 0)
                 {
-                    dx = (MRAND(1)) ? 1 : -1;
-                    dy = (MRAND(1)) ? 1 : -1;
+                    dx = random_::coin() ? 1 : -1;
+                    dy = random_::coin() ? 1 : -1;
                 }
                 dx += mmd->bl.x;
                 dy += mmd->bl.y;
@@ -1736,7 +1672,7 @@ int mob_unlocktarget(struct mob_data *md, tick_t tick)
     md->target_id = 0;
     md->state.attackable = false;
     md->state.skillstate = MobSkillState::MSS_IDLE;
-    md->next_walktime = tick + std::chrono::seconds(3) + std::chrono::milliseconds(MRAND(3000));
+    md->next_walktime = tick + std::chrono::seconds(3) + std::chrono::milliseconds(random_::to(3000));
     return 0;
 }
 
@@ -1760,9 +1696,8 @@ int mob_randomwalk(struct mob_data *md, tick_t tick)
         for (i = 0; i < retrycount; i++)
         {
             // Search of a movable place
-            int r = mt_random();
-            x = md->bl.x + r % (d * 2 + 1) - d;
-            y = md->bl.y + r / (d * 2 + 1) % (d * 2 + 1) - d;
+            x = md->bl.x + random_::in(-d, d);
+            y = md->bl.y + random_::in(-d, d);
             uint8_t c = map_getcell(md->bl.m, x, y);
             if (c != 1 && c != 5
                 && mob_walktoxy(md, x, y, 1) == 0)
@@ -1792,7 +1727,7 @@ int mob_randomwalk(struct mob_data *md, tick_t tick)
             else
                 c += speed;
         }
-        md->next_walktime = tick + std::chrono::seconds(3) + std::chrono::milliseconds(MRAND(3000)) + c;
+        md->next_walktime = tick + std::chrono::seconds(3) + std::chrono::milliseconds(random_::to(3000)) + c;
         md->state.skillstate = MobSkillState::MSS_WALK;
         return 1;
     }
@@ -1860,7 +1795,7 @@ void mob_ai_sub_hard(struct block_list *bl, tick_t tick)
     // It checks to see it was attacked first (if active, it is target change at 25% of probability).
     if (mode != MobMode::ZERO && md->attacked_id > 0
         && (!md->target_id || !md->state.attackable
-            || (bool(mode & MobMode::AGGRESSIVE) && MRAND(100) < 25)))
+            || (bool(mode & MobMode::AGGRESSIVE) && random_::chance({25, 100}))))
     {
         struct block_list *abl = map_id2bl(md->attacked_id);
         struct map_session_data *asd = NULL;
@@ -1971,7 +1906,8 @@ void mob_ai_sub_hard(struct block_list *bl, tick_t tick)
                         do
                         {
                             if (i == 0)
-                            {   // 最初はAEGISと同じ方法で検索
+                            {
+                                // 最初はAEGISと同じ方法で検索
                                 dx = tbl->x - md->bl.x;
                                 dy = tbl->y - md->bl.y;
                                 if (dx < 0)
@@ -1984,9 +1920,11 @@ void mob_ai_sub_hard(struct block_list *bl, tick_t tick)
                                     dy--;
                             }
                             else
-                            {   // だめならAthena式(ランダム)
-                                dx = tbl->x - md->bl.x + MRAND(3) - 1;
-                                dy = tbl->y - md->bl.y + MRAND(3) - 1;
+                            {
+                                // だめならAthena式(ランダム)
+                                // {0 1 2}
+                                dx = tbl->x - md->bl.x + random_::in(-1, 1);
+                                dy = tbl->y - md->bl.y + random_::in(-1, 1);
                             }
                             ret = mob_walktoxy(md, md->bl.x + dx, md->bl.y + dy, 0);
                             i++;
@@ -2114,7 +2052,7 @@ void mob_ai_sub_hard(struct block_list *bl, tick_t tick)
             //      yields 3000 * {0 3000 6000 9000 ... 5991000 5994000 5997000}
             //  I have reverted to the original logic, but I don't understand.
 #warning "I don't understand this code! It is either wrong now or was wrong before."
-            md->next_walktime = tick + std::chrono::seconds(MRAND(2));
+            md->next_walktime = tick + std::chrono::seconds(random_::to(2));
         }
 
         // Random movement
@@ -2190,13 +2128,14 @@ void mob_ai_sub_lazy(db_key_t, db_val_t data, tick_t tick)
             // Since PC is in the same map, somewhat better negligent processing is carried out.
 
             // It sometimes moves.
-            if (MRAND(1000) < MOB_LAZYMOVEPERC)
+            if (random_::chance(MOB_LAZYMOVEPERC))
                 mob_randomwalk(md, tick);
 
             // MOB which is not not the summons MOB but BOSS, either sometimes reboils.
-            else if (MRAND(1000) < MOB_LAZYWARPPERC && md->x0 <= 0
-                     && md->master_id != 0 && mob_db[md->mob_class].mexp <= 0
-                     && !bool(mob_db[md->mob_class].mode & MobMode::BOSS))
+            else if (random_::chance(MOB_LAZYWARPPERC)
+                    && md->x0 <= 0
+                    && md->master_id != 0
+                    && !bool(mob_db[md->mob_class].mode & MobMode::BOSS))
                 mob_spawn(md->bl.id);
 
         }
@@ -2205,13 +2144,14 @@ void mob_ai_sub_lazy(db_key_t, db_val_t data, tick_t tick)
             // Since PC is not even in the same map, suitable processing is carried out even if it takes.
 
             // MOB which is not BOSS which is not Summons MOB, either -- a case -- sometimes -- leaping
-            if (MRAND(1000) < MOB_LAZYWARPPERC && md->x0 <= 0
-                && md->master_id != 0 && mob_db[md->mob_class].mexp <= 0
+            if (random_::chance(MOB_LAZYWARPPERC)
+                && md->x0 <= 0
+                && md->master_id != 0
                 && !bool(mob_db[md->mob_class].mode & MobMode::BOSS))
                 mob_warp(md, -1, -1, -1, BeingRemoveWhy::NEGATIVE1);
         }
 
-        md->next_walktime = tick + std::chrono::seconds(5) + std::chrono::milliseconds(MRAND(10 * 1000));
+        md->next_walktime = tick + std::chrono::seconds(5) + std::chrono::milliseconds(random_::to(10 * 1000));
     }
 }
 
@@ -2270,16 +2210,17 @@ void mob_delay_item_drop(TimerData *, tick_t, struct delay_item_drop *ditem)
             != PickupFail::OKAY)
         {
             clif_additem(ditem->first_sd, 0, 0, flag);
-            map_addflooritem(&temp_item, 1, ditem->m, ditem->x, ditem->y,
-                              ditem->first_sd, ditem->second_sd,
-                              ditem->third_sd, 0);
+            map_addflooritem(&temp_item, 1,
+                    ditem->m, ditem->x, ditem->y,
+                    ditem->first_sd, ditem->second_sd, ditem->third_sd);
         }
         free(ditem);
         return;
     }
 
-    map_addflooritem(&temp_item, 1, ditem->m, ditem->x, ditem->y,
-                      ditem->first_sd, ditem->second_sd, ditem->third_sd, 0);
+    map_addflooritem(&temp_item, 1,
+            ditem->m, ditem->x, ditem->y,
+            ditem->first_sd, ditem->second_sd, ditem->third_sd);
 
     free(ditem);
 }
@@ -2305,16 +2246,16 @@ void mob_delay_item_drop2(TimerData *, tick_t, struct delay_item_drop2 *ditem)
         {
             clif_additem(ditem->first_sd, 0, 0, flag);
             map_addflooritem(&ditem->item_data, ditem->item_data.amount,
-                              ditem->m, ditem->x, ditem->y, ditem->first_sd,
-                              ditem->second_sd, ditem->third_sd, 0);
+                    ditem->m, ditem->x, ditem->y,
+                    ditem->first_sd, ditem->second_sd, ditem->third_sd);
         }
         free(ditem);
         return;
     }
 
-    map_addflooritem(&ditem->item_data, ditem->item_data.amount, ditem->m,
-                      ditem->x, ditem->y, ditem->first_sd, ditem->second_sd,
-                      ditem->third_sd, 0);
+    map_addflooritem(&ditem->item_data, ditem->item_data.amount,
+            ditem->m, ditem->x, ditem->y,
+            ditem->first_sd, ditem->second_sd, ditem->third_sd);
 
     free(ditem);
 }
@@ -2418,9 +2359,7 @@ int mob_damage(struct block_list *src, struct mob_data *md, int damage,
     tick_t tick = gettick();
     struct map_session_data *mvp_sd = NULL, *second_sd = NULL, *third_sd =
         NULL;
-    double tdmg, temp;
-    struct item item;
-    PickupFail ret;
+    double tdmg;
 
     nullpo_ret(md);        //srcはNULLで呼ばれる場合もあるので、他でチェック
 
@@ -2701,22 +2640,19 @@ int mob_damage(struct block_list *src, struct mob_data *md, int damage,
             for (int i = 0; i < 8; i++)
             {
                 struct delay_item_drop *ditem;
-                int drop_rate;
 
                 if (md->state.special_mob_ai >= 1 && battle_config.alchemist_summon_reward != 1)    // Added [Valaris]
                     break;      // End
 
                 if (mob_db[md->mob_class].dropitem[i].nameid <= 0)
                     continue;
-                drop_rate = mob_db[md->mob_class].dropitem[i].p;
-                if (drop_rate <= 0 && battle_config.drop_rate0item == 1)
-                    drop_rate = 1;
+                random_::Fixed<int, 10000> drop_rate = mob_db[md->mob_class].dropitem[i].p;
                 if (battle_config.drops_by_luk > 0 && sd && md)
-                    drop_rate += (sd->status.attrs[ATTR::LUK] * battle_config.drops_by_luk) / 100;   // drops affected by luk [Valaris]
+                    drop_rate.num += (sd->status.attrs[ATTR::LUK] * battle_config.drops_by_luk) / 100;   // drops affected by luk [Valaris]
                 if (sd && md && battle_config.pk_mode == 1
                     && (mob_db[md->mob_class].lv - sd->status.base_level >= 20))
-                    drop_rate *= 1.25;  // pk_mode increase drops if 20 level difference [Valaris]
-                if (drop_rate <= MRAND(10000))
+                    drop_rate.num *= 1.25;  // pk_mode increase drops if 20 level difference [Valaris]
+                if (!random_::chance(drop_rate))
                     continue;
 
                 ditem = (struct delay_item_drop *)
@@ -2756,53 +2692,6 @@ int mob_damage(struct block_list *src, struct mob_data *md, int damage,
                 }
             }
         }
-
-        // mvp処理
-        if (mvp_sd && mob_db[md->mob_class].mexp > 0)
-        {
-            int j;
-            int mexp = battle_get_mexp(&md->bl);
-            temp =
-                ((double) mexp * (double) battle_config.mvp_exp_rate *
-                 (9. + (double) count) / 1000.);
-            mexp = (temp > 2147483647.) ? 0x7fffffff : (int) temp;
-            if (mexp < 1)
-                mexp = 1;
-            clif_mvp_effect(mvp_sd);   // エフェクト
-            pc_gainexp(mvp_sd, mexp, 0);
-            for (j = 0; j < 3; j++)
-            {
-                int i = MRAND(3);
-                if (mob_db[md->mob_class].mvpitem[i].nameid <= 0)
-                    continue;
-                int drop_rate = mob_db[md->mob_class].mvpitem[i].p;
-                if (drop_rate <= 0 && battle_config.drop_rate0item == 1)
-                    drop_rate = 1;
-                if (drop_rate < battle_config.item_drop_mvp_min)
-                    drop_rate = battle_config.item_drop_mvp_min;
-                if (drop_rate > battle_config.item_drop_mvp_max)
-                    drop_rate = battle_config.item_drop_mvp_max;
-                if (drop_rate <= MRAND(10000))
-                    continue;
-                memset(&item, 0, sizeof(item));
-                item.nameid = mob_db[md->mob_class].mvpitem[i].nameid;
-                item.identify = !itemdb_isequip3(item.nameid);
-                if (mvp_sd->weight * 2 > mvp_sd->max_weight)
-                    map_addflooritem(&item, 1, mvp_sd->bl.m, mvp_sd->bl.x,
-                                      mvp_sd->bl.y, mvp_sd, second_sd,
-                                      third_sd, 1);
-                else if ((ret = pc_additem(mvp_sd, &item, 1))
-                        != PickupFail::OKAY)
-                {
-                    clif_additem(sd, 0, 0, ret);
-                    map_addflooritem(&item, 1, mvp_sd->bl.m, mvp_sd->bl.x,
-                                      mvp_sd->bl.y, mvp_sd, second_sd,
-                                      third_sd, 1);
-                }
-                break;
-            }
-        }
-
     }                           // [MouseJstr]
 
     // SCRIPT実行
@@ -2844,83 +2733,6 @@ int mob_damage(struct block_list *src, struct mob_data *md, int damage,
 }
 
 /*==========================================
- *
- *------------------------------------------
- */
-int mob_class_change(struct mob_data *md, int *value)
-{
-    tick_t tick = gettick();
-    int i, hp_rate, max_hp, mob_class, count = 0;
-
-    nullpo_ret(md);
-    nullpo_ret(value);
-
-    if (value[0] <= 1000 || value[0] > 2000)
-        return 0;
-    if (md->bl.prev == NULL)
-        return 0;
-
-    while (count < 5 && value[count] > 1000 && value[count] <= 2000)
-        count++;
-    if (count < 1)
-        return 0;
-
-    mob_class = value[MRAND(count)];
-    if (mob_class <= 1000 || mob_class > 2000)
-        return 0;
-
-    max_hp = battle_get_max_hp(&md->bl);
-    hp_rate = md->hp * 100 / max_hp;
-    md->mob_class = mob_class;
-    max_hp = battle_get_max_hp(&md->bl);
-    if (battle_config.monster_class_change_full_recover == 1)
-    {
-        md->hp = max_hp;
-        memset(md->dmglog, 0, sizeof(md->dmglog));
-    }
-    else
-        md->hp = max_hp * hp_rate / 100;
-    if (md->hp > max_hp)
-        md->hp = max_hp;
-    else if (md->hp < 1)
-        md->hp = 1;
-
-    memcpy(md->name, mob_db[mob_class].jname, 24);
-    memset(&md->state, 0, sizeof(md->state));
-    md->attacked_id = 0;
-    md->target_id = 0;
-    md->move_fail_count = 0;
-
-    md->stats[mob_stat::SPEED] = mob_db[md->mob_class].speed;
-    md->def_ele = mob_db[md->mob_class].element;
-
-    mob_changestate(md, MS::IDLE, 0);
-    skill_castcancel(&md->bl, 0);
-    md->state.skillstate = MobSkillState::MSS_IDLE;
-    md->last_thinktime = tick;
-    md->next_walktime = tick + std::chrono::seconds(5) + std::chrono::milliseconds(MRAND(50));
-    md->attackabletime = tick;
-    md->canmove_tick = tick;
-    md->sg_count = 0;
-
-    tick_t c = tick - std::chrono::hours(10);
-    for (i = 0; i < MAX_MOBSKILL; i++)
-        md->skilldelay[i] = c;
-    md->skillid = SkillID();
-    md->skilllv = 0;
-
-    if (md->lootitem == NULL
-        && bool(mob_db[mob_class].mode & MobMode::LOOTER))
-        md->lootitem = (struct item *)
-            calloc(LOOTITEM_SIZE, sizeof(struct item));
-
-    clif_clearchar(&md->bl, BeingRemoveWhy::GONE);
-    clif_spawnmob(md);
-
-    return 0;
-}
-
-/*==========================================
  * mob回復
  *------------------------------------------
  */
@@ -2999,14 +2811,16 @@ int mob_warp(struct mob_data *md, int m, int x, int y, BeingRemoveWhy type)
            && (i++) < 1000)
     {
         if (xs > 0 && ys > 0 && i < 250)
-        {                       // 指定位置付近の探索
-            x = MPRAND(bx, xs) - xs / 2;
-            y = MPRAND(by, ys) - ys / 2;
+        {
+            // 指定位置付近の探索
+            x = bx + random_::to(xs) - xs / 2;
+            y = by + random_::to(ys) - ys / 2;
         }
         else
-        {                       // 完全ランダム探索
-            x = MPRAND(1, (map[m].xs - 2));
-            y = MPRAND(1, (map[m].ys - 2));
+        {
+            // 完全ランダム探索
+            x = random_::in(1, map[m].xs - 2);
+            y = random_::in(1, map[m].ys - 2);
         }
     }
     md->dir = DIR::S;
@@ -3121,8 +2935,8 @@ int mob_summonslave(struct mob_data *md2, int *value, int amount, int flag)
             while ((x <= 0 || y <= 0 || (c = map_getcell(m, x, y)) == 1
                     || c == 5) && (i++) < 100)
             {
-                x = MPRAND(bx, 9) - 4;
-                y = MPRAND(by, 9) - 4;
+                x = bx + random_::in(-4, 4);
+                y = by + random_::in(-4, 4);
             }
             if (i >= 100)
             {
@@ -3530,7 +3344,7 @@ int mobskill_use(struct mob_data *md, tick_t tick,
         }
 
         // 確率判定
-        if (flag && MRAND(10000) < ms[ii].permillage)
+        if (flag && random_::chance({ms[ii].permillage, 10000}))
         {
 
             if (skill_get_inf(ms[ii].skill_id) & 2)
@@ -3636,23 +3450,11 @@ int mob_makedummymobdb(int mob_class)
     mob_db[mob_class].adelay = 1000;
     mob_db[mob_class].amotion = 500;
     mob_db[mob_class].dmotion = 500;
-    mob_db[mob_class].dropitem[0].nameid = 909; // Jellopy
-    mob_db[mob_class].dropitem[0].p = 1000;
-    for (i = 1; i < 8; i++)
+    for (i = 0; i < 8; i++)
     {
         mob_db[mob_class].dropitem[i].nameid = 0;
-        mob_db[mob_class].dropitem[i].p = 0;
-    }
-    // Item1,Item2
-    mob_db[mob_class].mexp = 0;
-    mob_db[mob_class].mexpper = 0;
-    for (i = 0; i < 3; i++)
-    {
-        mob_db[mob_class].mvpitem[i].nameid = 0;
-        mob_db[mob_class].mvpitem[i].p = 0;
+        mob_db[mob_class].dropitem[i].p.num = 0;
     }
-    for (i = 0; i < MAX_RANDOMMONSTER; i++)
-        mob_db[mob_class].summonper[i] = 0;
     return 0;
 }
 
@@ -3760,63 +3562,15 @@ int mob_readdb(void)
 
             for (int i = 0; i < 8; i++)
             {
-                int rate = 0, ratemin, ratemax;
                 mob_db[mob_class].dropitem[i].nameid = atoi(str[29 + i * 2]);
-                ItemType type = itemdb_type(mob_db[mob_class].dropitem[i].nameid);
-                if (type == ItemType::USE)
-                {               // Added [Valaris]
-                    rate = battle_config.item_rate_heal;
-                    ratemin = battle_config.item_drop_heal_min;
-                    ratemax = battle_config.item_drop_heal_max;
-                }
-                else if (type == ItemType::_2)
-                {
-                    rate = battle_config.item_rate_use;
-                    ratemin = battle_config.item_drop_use_min;
-                    ratemax = battle_config.item_drop_use_max;  // End
-                }
-                else if (type == ItemType::WEAPON
-                    || type == ItemType::ARMOR
-                    || type == ItemType::_8)
-                {
-                    rate = battle_config.item_rate_equip;
-                    ratemin = battle_config.item_drop_equip_min;
-                    ratemax = battle_config.item_drop_equip_max;
-                }
-                else if (type == ItemType::_6)
-                {
-                    rate = battle_config.item_rate_card;
-                    ratemin = battle_config.item_drop_card_min;
-                    ratemax = battle_config.item_drop_card_max;
-                }
-                else
-                {
-                    rate = battle_config.item_rate_common;
-                    ratemin = battle_config.item_drop_common_min;
-                    ratemax = battle_config.item_drop_common_max;
-                }
-                rate = (rate / 100) * atoi(str[30 + i * 2]);
-                rate =
-                    (rate < ratemin) ? ratemin : (rate >
-                                                  ratemax) ? ratemax : rate;
-                mob_db[mob_class].dropitem[i].p = rate;
-            }
-            // Item1,Item2
-            mob_db[mob_class].mexp =
-                atoi(str[45]) * battle_config.mvp_exp_rate / 100;
-            mob_db[mob_class].mexpper = atoi(str[46]);
-            for (int i = 0; i < 3; i++)
-            {
-                mob_db[mob_class].mvpitem[i].nameid = atoi(str[47 + i * 2]);
-                mob_db[mob_class].mvpitem[i].p =
-                    atoi(str[48 + i * 2]) * battle_config.mvp_item_rate /
-                    100;
+                int rate = atoi(str[30 + i * 2]);
+                if (rate < 1) rate = 1;
+                if (rate > 10000) rate = 10000;
+                mob_db[mob_class].dropitem[i].p.num = rate;
             }
             mob_db[mob_class].mutations_nr = atoi(str[55]);
             mob_db[mob_class].mutation_power = atoi(str[56]);
 
-            for (int i = 0; i < MAX_RANDOMMONSTER; i++)
-                mob_db[mob_class].summonper[i] = 0;
             mob_db[mob_class].maxskill = 0;
 
             mob_db[mob_class].sex = 0;
@@ -3839,61 +3593,6 @@ int mob_readdb(void)
 }
 
 /*==========================================
- * Reading of random monster data
- *------------------------------------------
- */
-static
-int mob_read_randommonster(void)
-{
-    FILE *fp;
-    char line[1024];
-    char *str[10], *p;
-    int i, j;
-
-    const char *mobfile[] = {
-        "db/mob_branch.txt",
-        "db/mob_poring.txt",
-        "db/mob_boss.txt"
-    };
-
-    for (i = 0; i < MAX_RANDOMMONSTER; i++)
-    {
-        mob_db[0].summonper[i] = 1002;  // 設定し忘れた場合はポリンが出るようにしておく
-        fp = fopen_(mobfile[i], "r");
-        if (fp == NULL)
-        {
-            PRINTF("can't read %s\n", mobfile[i]);
-            return -1;
-        }
-        while (fgets(line, 1020, fp))
-        {
-            int mob_class, per;
-            if (line[0] == '/' && line[1] == '/')
-                continue;
-            memset(str, 0, sizeof(str));
-            for (j = 0, p = line; j < 3 && p; j++)
-            {
-                str[j] = p;
-                p = strchr(p, ',');
-                if (p)
-                    *p++ = 0;
-            }
-
-            if (str[0] == NULL || str[2] == NULL)
-                continue;
-
-            mob_class = atoi(str[0]);
-            per = atoi(str[2]);
-            if ((mob_class > 1000 && mob_class <= 2000) || mob_class == 0)
-                mob_db[mob_class].summonper[i] = per;
-        }
-        fclose_(fp);
-        PRINTF("read %s done\n", mobfile[i]);
-    }
-    return 0;
-}
-
-/*==========================================
  * db/mob_skill_db.txt reading
  *------------------------------------------
  */
@@ -4054,7 +3753,6 @@ int do_init_mob(void)
 {
     mob_readdb();
 
-    mob_read_randommonster();
     mob_readskilldb();
 
     add_timer_interval(gettick() + MIN_MOBTHINKTIME,
diff --git a/src/map/mob.hpp b/src/map/mob.hpp
index 3a7ce3d..16715c4 100644
--- a/src/map/mob.hpp
+++ b/src/map/mob.hpp
@@ -5,13 +5,12 @@
 
 #include "../common/mmo.hpp"
 #include "../common/timer.t.hpp"
+#include "../common/random.t.hpp"
 
 #include "clif.t.hpp"
 #include "map.hpp"
 #include "skill.t.hpp"
 
-constexpr int MAX_RANDOMMONSTER = 3;
-
 struct mob_skill
 {
     MobSkillState state;
@@ -22,7 +21,6 @@ struct mob_skill
     short cancel;
     MobSkillCondition cond1;
     int cond2i;
-    SkillID cond2sk() { return SkillID(cond2i); }
     MobSkillTarget target;
     int val[5];
     short emotion;
@@ -44,20 +42,15 @@ struct mob_db
     LevelElement element;
     MobMode mode;
     int speed, adelay, amotion, dmotion;
-    int mexp, mexpper;
     int mutations_nr, mutation_power;
     struct
     {
-        int nameid, p;
+        int nameid;
+        random_::Fixed<int, 10000> p;
     } dropitem[8];
-    struct
-    {
-        int nameid, p;
-    } mvpitem[3];
     int sex;
     short hair, hair_color, weapon, shield, head_top, head_mid, head_buttom, option, clothes_color; // [Valaris]
     int equip;                 // [Valaris]
-    int summonper[MAX_RANDOMMONSTER];
     int maxskill;
     struct mob_skill skill[MAX_MOBSKILL];
 };
@@ -72,11 +65,6 @@ int mob_once_spawn_area(struct map_session_data *sd,
         const char *mapname, int x0, int y0, int x1, int y1,
         const char *mobname, int class_, int amount, const char *event);
 
-int mob_spawn_guardian(struct map_session_data *sd,
-        const char *mapname, int x, int y,
-        const char *mobname, int class_, int amount,
-        const char *event, int guardian);    // Spawning Guardians [Valaris]
-
 int mob_target(struct mob_data *md, struct block_list *bl, int dist);
 int mob_stop_walking(struct mob_data *md, int type);
 int mob_stopattack(struct mob_data *);
@@ -104,7 +92,6 @@ int mob_deleteslave(struct mob_data *md);
 int mob_counttargeted(struct mob_data *md, struct block_list *src,
         ATK target_lv);
 
-int mob_class_change(struct mob_data *md, int *value);
 int mob_warp(struct mob_data *md, int m, int x, int y, BeingRemoveWhy type);
 
 int mobskill_use(struct mob_data *md, tick_t tick, MobSkillCondition event);
diff --git a/src/map/npc.cpp b/src/map/npc.cpp
index 2aa9480..610a274 100644
--- a/src/map/npc.cpp
+++ b/src/map/npc.cpp
@@ -1674,8 +1674,6 @@ int npc_parse_mapflag(char *w1, char *, char *w3, char *w4)
     int m;
     char mapname[24], savemap[16];
     int savex, savey;
-    char drop_arg1[16], drop_arg2[16];
-    int drop_id = 0, drop_type = 0, drop_per = 0;
 
     // 引数の個数チェック
 //  if (    sscanf(w1,"%[^,],%d,%d,%d",mapname,&x,&y,&dir) != 4 )
@@ -1743,39 +1741,6 @@ int npc_parse_mapflag(char *w1, char *, char *w3, char *w4)
     {
         map[m].flag.pvp_noparty = 1;
     }
-    else if (strcasecmp(w3, "pvp_nightmaredrop") == 0)
-    {
-        if (sscanf(w4, "%[^,],%[^,],%d", drop_arg1, drop_arg2, &drop_per) ==
-            3)
-        {
-            int i;
-            if (strcmp(drop_arg1, "random") == 0)
-                drop_id = -1;
-            else if (itemdb_exists((drop_id = atoi(drop_arg1))) == NULL)
-                drop_id = 0;
-            if (strcmp(drop_arg2, "inventory") == 0)
-                drop_type = 1;
-            else if (strcmp(drop_arg2, "equip") == 0)
-                drop_type = 2;
-            else if (strcmp(drop_arg2, "all") == 0)
-                drop_type = 3;
-
-            if (drop_id != 0)
-            {
-                for (i = 0; i < MAX_DROP_PER_MAP; i++)
-                {
-                    if (map[m].drop_list[i].drop_id == 0)
-                    {
-                        map[m].drop_list[i].drop_id = drop_id;
-                        map[m].drop_list[i].drop_type = drop_type;
-                        map[m].drop_list[i].drop_per = drop_per;
-                        break;
-                    }
-                }
-                map[m].flag.pvp_nightmaredrop = 1;
-            }
-        }
-    }
     else if (strcasecmp(w3, "pvp_nocalcrank") == 0)
     {
         map[m].flag.pvp_nocalcrank = 1;
diff --git a/src/map/path.cpp b/src/map/path.cpp
index 1a4385b..9c6ea28 100644
--- a/src/map/path.cpp
+++ b/src/map/path.cpp
@@ -1,5 +1,5 @@
 #include "../common/cxxstdio.hpp"
-#include "../common/mt_rand.hpp"
+#include "../common/random.hpp"
 #include "../common/nullpo.hpp"
 
 #include "battle.hpp"
@@ -222,57 +222,6 @@ int can_move(struct map_data *m, int x0, int y0, int x1, int y1, int flag)
 }
 
 /*==========================================
- * (x0,y0)から(dx,dy)方向へcountセル分
- * 吹き飛ばしたあとの座標を所得
- *------------------------------------------
- */
-int path_blownpos(int m, int x0, int y0, int dx, int dy, int count)
-{
-    struct map_data *md;
-
-    if (!map[m].gat)
-        return -1;
-    md = &map[m];
-
-    if (count > 15)
-    {                           // 最大10マスに制限
-        if (battle_config.error_log)
-            PRINTF("path_blownpos: count too many %d !\n", count);
-        count = 15;
-    }
-    if (dx > 1 || dx < -1 || dy > 1 || dy < -1)
-    {
-        if (battle_config.error_log)
-            PRINTF("path_blownpos: illeagal dx=%d or dy=%d !\n", dx, dy);
-        dx = (dx >= 0) ? 1 : ((dx < 0) ? -1 : 0);
-        dy = (dy >= 0) ? 1 : ((dy < 0) ? -1 : 0);
-    }
-
-    while ((count--) > 0 && (dx != 0 || dy != 0))
-    {
-        if (!can_move(md, x0, y0, x0 + dx, y0 + dy, 0))
-        {
-            int fx = (dx != 0 && can_move(md, x0, y0, x0 + dx, y0, 0));
-            int fy = (dy != 0 && can_move(md, x0, y0, x0, y0 + dy, 0));
-            if (fx && fy)
-            {
-                if (MRAND(2))
-                    dx = 0;
-                else
-                    dy = 0;
-            }
-            if (!fx)
-                dx = 0;
-            if (!fy)
-                dy = 0;
-        }
-        x0 += dx;
-        y0 += dy;
-    }
-    return (x0 << 16) | y0;
-}
-
-/*==========================================
  * path探索 (x0,y0)->(x1,y1)
  *------------------------------------------
  */
diff --git a/src/map/pc.cpp b/src/map/pc.cpp
index bbd59aa..c5fa07c 100644
--- a/src/map/pc.cpp
+++ b/src/map/pc.cpp
@@ -5,7 +5,7 @@
 #include <cstring>
 
 #include "../common/cxxstdio.hpp"
-#include "../common/mt_rand.hpp"
+#include "../common/random.hpp"
 #include "../common/nullpo.hpp"
 #include "../common/socket.hpp"
 #include "../common/timer.hpp"
@@ -611,84 +611,6 @@ int pc_isequip(struct map_session_data *sd, int n)
 }
 
 /*==========================================
- * Weapon Breaking [Valaris]
- *------------------------------------------
- */
-int pc_breakweapon(struct map_session_data *sd)
-{
-    struct item_data *item;
-    int i;
-
-    if (sd == NULL)
-        return -1;
-    if (!MRAND(100))
-        return 0;
-
-    for (i = 0; i < MAX_INVENTORY; i++)
-    {
-        if (bool(sd->status.inventory[i].equip)
-            && bool(sd->status.inventory[i].equip & EPOS::WEAPON)
-            && !sd->status.inventory[i].broken)
-        {
-            item = sd->inventory_data[i];
-            sd->status.inventory[i].broken = 1;
-            //pc_unequipitem(sd,i,CalcStatus::NOW);
-            if (bool(sd->status.inventory[i].equip)
-                && bool(sd->status.inventory[i].equip & EPOS::WEAPON)
-                && sd->status.inventory[i].broken == 1)
-            {
-                std::string output = STRPRINTF("%s has broken.", item->jname);
-                clif_emotion(&sd->bl, 23);
-                clif_displaymessage(sd->fd, output);
-                clif_equiplist(sd);
-                skill_status_change_start(&sd->bl, StatusChange::SC_BROKNWEAPON, 0, interval_t::zero());
-            }
-        }
-        if (sd->status.inventory[i].broken == 1)
-            return 0;
-    }
-
-    return 0;
-}
-
-/*==========================================
- * Armor Breaking [Valaris]
- *------------------------------------------
- */
-int pc_breakarmor(struct map_session_data *sd)
-{
-    if (sd == NULL)
-        return -1;
-    if (!MRAND(100))
-        return 0;
-
-    for (int i = 0; i < MAX_INVENTORY; i++)
-    {
-        if (bool(sd->status.inventory[i].equip)
-            && bool(sd->status.inventory[i].equip & EPOS::MISC1)
-            && !sd->status.inventory[i].broken)
-        {
-            struct item_data *item = sd->inventory_data[i];
-            sd->status.inventory[i].broken = 1;
-            if (bool(sd->status.inventory[i].equip)
-                && bool(sd->status.inventory[i].equip & EPOS::MISC1)
-                && sd->status.inventory[i].broken == 1)
-            {
-                std::string output = STRPRINTF("%s has broken.",
-                        item->jname);
-                clif_emotion(&sd->bl, 23);
-                clif_displaymessage(sd->fd, output);
-                clif_equiplist(sd);
-                skill_status_change_start(&sd->bl, StatusChange::SC_BROKNARMOR, 0, interval_t::zero());
-            }
-        }
-        if (sd->status.inventory[i].broken == 1)
-            return 0;
-    }
-    return 0;
-}
-
-/*==========================================
  * session idに問題無し
  * char鯖から送られてきたステータスを設定
  *------------------------------------------
@@ -2238,8 +2160,9 @@ int pc_dropitem(struct map_session_data *sd, int n, int amount)
         sd->status.inventory[n].amount < amount ||
         sd->trade_partner != 0 || sd->status.inventory[n].amount <= 0)
         return 1;
-    map_addflooritem(&sd->status.inventory[n], amount, sd->bl.m, sd->bl.x,
-                      sd->bl.y, NULL, NULL, NULL, 0);
+    map_addflooritem(&sd->status.inventory[n], amount,
+            sd->bl.m, sd->bl.x, sd->bl.y,
+            NULL, NULL, NULL);
     pc_delitem(sd, n, amount, 0);
 
     return 0;
@@ -2432,131 +2355,6 @@ int pc_cart_delitem(struct map_session_data *sd, int n, int amount, int)
     return 0;
 }
 
-/*==========================================
- * スティル品公開
- *------------------------------------------
- */
-static
-void pc_show_steal(struct block_list *bl,
-        struct map_session_data *sd, int itemid, int type)
-{
-    nullpo_retv(bl);
-    nullpo_retv(sd);
-
-    std::string output;
-    if (!type)
-    {
-        struct item_data *item = itemdb_exists(itemid);
-        if (item == NULL)
-            output = STRPRINTF("%s stole an Unknown_Item.",
-                    sd->status.name);
-        else
-            output = STRPRINTF("%s stole %s.",
-                    sd->status.name, item->jname);
-        clif_displaymessage(((struct map_session_data *) bl)->fd, output);
-    }
-    else
-    {
-        output = STRPRINTF(
-                "%s has not stolen the item because of being  overweight.",
-                sd->status.name);
-        clif_displaymessage(((struct map_session_data *) bl)->fd, output);
-    }
-}
-
-/*==========================================
- *
- *------------------------------------------
- */
-//** pc.c: Small Steal Item fix by fritz
-int pc_steal_item(struct map_session_data *sd, struct block_list *bl)
-{
-    if (sd != NULL && bl != NULL && bl->type == BL::MOB)
-    {
-        int i, skill, rate, itemid, count;
-        struct mob_data *md;
-        md = (struct mob_data *) bl;
-        if (!md->state.steal_flag
-            && mob_db[md->mob_class].mexp <= 0
-            && !bool(mob_db[md->mob_class].mode & MobMode::BOSS))
-        {
-            skill = sd->paramc[ATTR::DEX] - mob_db[md->mob_class].attrs[ATTR::DEX] + 10;
-
-            if (0 < skill)
-            {
-                for (count = 8; count <= 8 && count != 0; count--)
-                {
-                    i = MRAND(8);
-                    itemid = mob_db[md->mob_class].dropitem[i].nameid;
-
-                    if (itemid > 0 && itemdb_type(itemid) != ItemType::_6)
-                    {
-                        rate =
-                            (mob_db[md->mob_class].dropitem[i].p /
-                             battle_config.item_rate_common * 100 * skill) /
-                            100;
-
-                        if (MRAND(10000) < rate)
-                        {
-                            struct item tmp_item;
-                            memset(&tmp_item, 0, sizeof(tmp_item));
-                            tmp_item.nameid = itemid;
-                            tmp_item.amount = 1;
-                            tmp_item.identify = 1;
-                            PickupFail flag = pc_additem(sd, &tmp_item, 1);
-                            if (battle_config.show_steal_in_same_party)
-                            {
-                                party_foreachsamemap(
-                                        std::bind(pc_show_steal, ph::_1, sd, tmp_item.nameid, 0), sd, 1);
-                            }
-
-                            if (flag != PickupFail::OKAY)
-                            {
-                                if (battle_config.show_steal_in_same_party)
-                                {
-                                    party_foreachsamemap(
-                                            std::bind(pc_show_steal, ph::_1, sd, tmp_item.nameid, 1), sd, 1);
-                                }
-
-                                clif_additem(sd, 0, 0, flag);
-                            }
-                            md->state.steal_flag = 1;
-                            return 1;
-                        }
-                    }
-                }
-            }
-        }
-    }
-    return 0;
-}
-
-/*==========================================
- *
- *------------------------------------------
- */
-int pc_steal_coin(struct map_session_data *sd, struct block_list *bl)
-{
-    if (sd != NULL && bl != NULL && bl->type == BL::MOB)
-    {
-        int rate;
-        struct mob_data *md = (struct mob_data *) bl;
-        if (md && !md->state.steal_coin_flag)
-        {
-            rate = (sd->status.base_level - mob_db[md->mob_class].lv) * 3
-                + sd->paramc[ATTR::DEX] * 2 + sd->paramc[ATTR::LUK] * 2;
-            if (MRAND(1000) < rate)
-            {
-                pc_getzeny(sd, mob_db[md->mob_class].lv * 10 + MRAND(100));
-                md->state.steal_coin_flag = 1;
-                return 1;
-            }
-        }
-    }
-
-    return 0;
-}
-
 //
 //
 //
@@ -2645,8 +2443,8 @@ int pc_setpos(struct map_session_data *sd, const char *mapname_org, int x, int y
         }
         do
         {
-            x = MRAND(map[m].xs - 2) + 1;
-            y = MRAND(map[m].ys - 2) + 1;
+            x = random_::in(1, map[m].xs - 2);
+            y = random_::in(1, map[m].ys - 2);
         }
         while ((c = read_gat(m, x, y)) == 1 || c == 5);
     }
@@ -2693,8 +2491,8 @@ int pc_randomwarp(struct map_session_data *sd, BeingRemoveWhy type)
 
     do
     {
-        x = MRAND(map[m].xs - 2) + 1;
-        y = MRAND(map[m].ys - 2) + 1;
+        x = random_::in(1, map[m].xs - 2);
+        y = random_::in(1, map[m].ys - 2);
     }
     while (((c = read_gat(m, x, y)) == 1 || c == 5) && (i++) < 1000);
 
@@ -3738,7 +3536,7 @@ int pc_resetskill(struct map_session_data *sd)
 int pc_damage(struct block_list *src, struct map_session_data *sd,
                int damage)
 {
-    int i = 0, j = 0;
+    int i = 0;
 
     nullpo_ret(sd);
 
@@ -3876,70 +3674,7 @@ int pc_damage(struct block_list *src, struct map_session_data *sd,
             clif_updatestatus(sd, SP::JOBEXP);
         }
     }
-    //ナイトメアモードアイテムドロップ
-    if (map[sd->bl.m].flag.pvp_nightmaredrop)
-    {                           // Moved this outside so it works when PVP isnt enabled and during pk mode [Ancyker]
-        for (j = 0; j < MAX_DROP_PER_MAP; j++)
-        {
-            int id = map[sd->bl.m].drop_list[j].drop_id;
-            int type = map[sd->bl.m].drop_list[j].drop_type;
-            int per = map[sd->bl.m].drop_list[j].drop_per;
-            if (id == 0)
-                continue;
-            if (id == -1)
-            {                   //ランダムドロップ
-                int eq_num = 0, eq_n[MAX_INVENTORY];
-                memset(eq_n, 0, sizeof(eq_n));
-                //先ず装備しているアイテム数をカウント
-                for (i = 0; i < MAX_INVENTORY; i++)
-                {
-                    int k;
-                    if ((type == 1 && !bool(sd->status.inventory[i].equip))
-                        || (type == 2 && bool(sd->status.inventory[i].equip))
-                        || type == 3)
-                    {
-                        //InventoryIndexを格納
-                        for (k = 0; k < MAX_INVENTORY; k++)
-                        {
-                            if (eq_n[k] <= 0)
-                            {
-                                eq_n[k] = i;
-                                break;
-                            }
-                        }
-                        eq_num++;
-                    }
-                }
-                if (eq_num > 0)
-                {
-                    int n = eq_n[MRAND(eq_num)];  //該当アイテムの中からランダム
-                    if (MRAND(10000) < per)
-                    {
-                        if (bool(sd->status.inventory[n].equip))
-                            pc_unequipitem(sd, n, CalcStatus::NOW);
-                        pc_dropitem(sd, n, 1);
-                    }
-                }
-            }
-            else if (id > 0)
-            {
-                for (i = 0; i < MAX_INVENTORY; i++)
-                {
-                    if (sd->status.inventory[i].nameid == id    //ItemIDが一致していて
-                        && MRAND(10000) < per  //ドロップ率判定もOKで
-                        && ((type == 1 && !bool(sd->status.inventory[i].equip))   //タイプ判定もOKならドロップ
-                            || (type == 2 && bool(sd->status.inventory[i].equip))
-                            || type == 3))
-                    {
-                        if (bool(sd->status.inventory[i].equip))
-                            pc_unequipitem(sd, i, CalcStatus::NOW);
-                        pc_dropitem(sd, i, 1);
-                        break;
-                    }
-                }
-            }
-        }
-    }
+
     // pvp
     if (map[sd->bl.m].flag.pvp && !battle_config.pk_mode)
     {                           // disable certain pvp functions on pk_mode [Valaris]
diff --git a/src/map/pc.hpp b/src/map/pc.hpp
index 18e72e9..12935b5 100644
--- a/src/map/pc.hpp
+++ b/src/map/pc.hpp
@@ -61,9 +61,6 @@ int pc_authfail(int);
 
 EPOS pc_equippoint(struct map_session_data *sd, int n);
 
-int pc_breakweapon(struct map_session_data *sd);  // weapon breaking [Valaris]
-int pc_breakarmor(struct map_session_data *sd);   // armor breaking [Valaris]
-
 int pc_checkskill(struct map_session_data *sd, SkillID skill_id);
 int pc_checkequip(struct map_session_data *sd, EPOS pos);
 
@@ -96,9 +93,6 @@ int pc_bonus(struct map_session_data *, SP, int);
 int pc_bonus2(struct map_session_data *sd, SP, int, int);
 int pc_skill(struct map_session_data *, SkillID, int, int);
 
-int pc_steal_item(struct map_session_data *sd, struct block_list *bl);
-int pc_steal_coin(struct map_session_data *sd, struct block_list *bl);
-
 int pc_attack(struct map_session_data *, int, int);
 int pc_stopattack(struct map_session_data *);
 
diff --git a/src/map/script.cpp b/src/map/script.cpp
index 22e2f16..e7f957d 100644
--- a/src/map/script.cpp
+++ b/src/map/script.cpp
@@ -12,7 +12,7 @@
 #include "../common/db.hpp"
 #include "../common/extract.hpp"
 #include "../common/lock.hpp"
-#include "../common/mt_rand.hpp"
+#include "../common/random.hpp"
 #include "../common/socket.hpp"
 #include "../common/utils.hpp"
 #include "../common/timer.hpp"
@@ -1550,26 +1550,18 @@ void builtin_menu(ScriptState *st)
 static
 void builtin_rand(ScriptState *st)
 {
-    int range, min, max;
-
     if (st->end > st->start + 3)
     {
-        min = conv_num(st, &(st->stack->stack_data[st->start + 2]));
-        max = conv_num(st, &(st->stack->stack_data[st->start + 3]));
-        if (max < min)
-        {
-            int tmp;
-            tmp = min;
-            min = max;
-            max = tmp;
-        }
-        range = max - min + 1;
-        push_val(st->stack, ScriptCode::INT, (range <= 0 ? 0 : MRAND(range)) + min);
+        int min = conv_num(st, &(st->stack->stack_data[st->start + 2]));
+        int max = conv_num(st, &(st->stack->stack_data[st->start + 3]));
+        if (min > max)
+            std::swap(max, min);
+        push_val(st->stack, ScriptCode::INT, random_::in(min, max));
     }
     else
     {
-        range = conv_num(st, &(st->stack->stack_data[st->start + 2]));
-        push_val(st->stack, ScriptCode::INT, range <= 0 ? 0 : MRAND(range));
+        int range = conv_num(st, &(st->stack->stack_data[st->start + 2]));
+        push_val(st->stack, ScriptCode::INT, range <= 0 ? 0 : random_::to(range));
     }
 }
 
@@ -2111,22 +2103,12 @@ void builtin_getitem(ScriptState *st)
     {
         return;               //return if amount <=0, skip the useles iteration
     }
-    bool flag1 = false;
-    //Violet Box, Blue Box, etc - random item pick
-    if (nameid < 0)
-    {                           // ランダム
-        nameid = itemdb_searchrandomid(-nameid);
-        flag1 = 1;
-    }
 
     if (nameid > 0)
     {
         memset(&item_tmp, 0, sizeof(item_tmp));
         item_tmp.nameid = nameid;
-        if (!flag1)
-            item_tmp.identify = 1;
-        else
-            item_tmp.identify = !itemdb_isequip3(nameid);
+        item_tmp.identify = 1;
         if (st->end > st->start + 5)    //アイテムを指定したIDに渡す
             sd = map_id2sd(conv_num(st, &(st->stack->stack_data[st->start + 5])));
         if (sd == NULL)         //アイテムを渡す相手がいなかったらお帰り
@@ -2135,8 +2117,9 @@ void builtin_getitem(ScriptState *st)
         if ((flag = pc_additem(sd, &item_tmp, amount)) != PickupFail::OKAY)
         {
             clif_additem(sd, 0, 0, flag);
-            map_addflooritem(&item_tmp, amount, sd->bl.m, sd->bl.x, sd->bl.y,
-                              NULL, NULL, NULL, 0);
+            map_addflooritem(&item_tmp, amount,
+                    sd->bl.m, sd->bl.x, sd->bl.y,
+                    NULL, NULL, NULL);
         }
     }
 
@@ -2180,12 +2163,6 @@ void builtin_makeitem(ScriptState *st)
     else
         m = map_mapname2mapid(mapname);
 
-    if (nameid < 0)
-    {                           // ランダム
-        nameid = itemdb_searchrandomid(-nameid);
-        flag = 1;
-    }
-
     if (nameid > 0)
     {
         memset(&item_tmp, 0, sizeof(item_tmp));
@@ -2195,8 +2172,7 @@ void builtin_makeitem(ScriptState *st)
         else
             item_tmp.identify = !itemdb_isequip3(nameid);
 
-//      clif_additem(sd,0,0,flag);
-        map_addflooritem(&item_tmp, amount, m, x, y, NULL, NULL, NULL, 0);
+        map_addflooritem(&item_tmp, amount, m, x, y, NULL, NULL, NULL);
     }
 
 }
diff --git a/src/map/skill.cpp b/src/map/skill.cpp
index d1d5c38..8a2deb2 100644
--- a/src/map/skill.cpp
+++ b/src/map/skill.cpp
@@ -6,7 +6,7 @@
 #include <ctime>
 
 #include "../common/cxxstdio.hpp"
-#include "../common/mt_rand.hpp"
+#include "../common/random.hpp"
 #include "../common/nullpo.hpp"
 #include "../common/socket.hpp"
 #include "../common/timer.hpp"
@@ -210,7 +210,7 @@ int skill_additional_effect(struct block_list *src, struct block_list *bl,
     {
         case SkillID::NPC_POISON:
             // blame Fate for this
-            if (MRAND(100) < 50 - (sc_def_vit >> 2) - (sc_def_phys_shield_spell) + (skilllv >> 2))
+            if (random_::chance({50 - (sc_def_vit >> 2) - (sc_def_phys_shield_spell) + (skilllv >> 2), 100}))
                 skill_status_change_start(bl, StatusChange::SC_POISON, skilllv, static_cast<interval_t>(skilllv));
             break;
     }
@@ -327,22 +327,22 @@ int skill_attack(BF attack_type, struct block_list *src,
         int hp = 0, sp = 0;
         nullpo_ret(sd);
         if (sd->hp_drain_rate && dmg.damage > 0
-            && MRAND(100) < sd->hp_drain_rate)
+            && random_::chance({sd->hp_drain_rate, 100}))
         {
             hp += (dmg.damage * sd->hp_drain_per) / 100;
         }
         if (sd->hp_drain_rate_ && dmg.damage2 > 0
-            && MRAND(100) < sd->hp_drain_rate_)
+            && random_::chance({sd->hp_drain_rate_, 100}))
         {
             hp += (dmg.damage2 * sd->hp_drain_per_) / 100;
         }
         if (sd->sp_drain_rate > 0 && dmg.damage > 0
-            && MRAND(100) < sd->sp_drain_rate)
+            && random_::chance({sd->sp_drain_rate, 100}))
         {
             sp += (dmg.damage * sd->sp_drain_per) / 100;
         }
         if (sd->sp_drain_rate_ > 0 && dmg.damage2 > 0
-            && MRAND(100) < sd->sp_drain_rate_)
+            && random_::chance({sd->sp_drain_rate_, 100}))
         {
             sp += (dmg.damage2 * sd->sp_drain_per_) / 100;
         }
@@ -917,7 +917,7 @@ void skill_status_change_timer(TimerData *tid, tick_t tick, int id, StatusChange
                 const int resist_poison =
                     skill_power_bl(bl, SkillID::TMW_RESIST_POISON) >> 3;
                 if (resist_poison)
-                    sc_data[type].val1 -= MRAND(resist_poison + 1);
+                    sc_data[type].val1 -= random_::in(0, resist_poison);
 
                 if ((--sc_data[type].val1) > 0)
                 {