diff --git a/server/gameserver/creature.cc b/server/gameserver/creature.cc
index a1e780a..5a3cf20 100644
--- a/server/gameserver/creature.cc
+++ b/server/gameserver/creature.cc
@@ -2757,3 +2757,8 @@ Weapon* Creature::ChooseNextSpecWeapon(int curr_weapon_slot_id)
     }
     return next_weapon;
 }
+
+void Creature::OnBattleStart(Room* room)
+{
+
+}
diff --git a/server/gameserver/creature.h b/server/gameserver/creature.h
index 5b9670c..58ee4d4 100644
--- a/server/gameserver/creature.h
+++ b/server/gameserver/creature.h
@@ -89,6 +89,7 @@ class Creature : public MoveableEntity
     virtual bool Attackable(Room* room) override;
     virtual bool ReceiveExplosionDmg(Explosion* explosion) override;
     virtual bool IsCreature(Room* room)  override { return true;};
+    virtual void OnBattleStart(Room* room) override;
     bool HasBuffEffect(int buff_effect_id);
     Buff* GetBuffByEffectId(int effect_id);
     Buff* GetBuffById(int buff_id);
diff --git a/server/gameserver/entity.h b/server/gameserver/entity.h
index a4f7d03..f8e90c2 100644
--- a/server/gameserver/entity.h
+++ b/server/gameserver/entity.h
@@ -40,6 +40,7 @@ class Entity
     virtual void OnExplosionHit(Explosion* explosion) {};
     virtual void OnAddToTargetPartObject(Entity* target) {};
     virtual void OnRemoveFromTargetPartObject(Entity* target) {};
+    virtual void OnBattleStart(Room* room) {};
     virtual bool CanSeeMe(Human* hum) { return true; };
     virtual bool Attackable(Room* room) { return false; };
     virtual bool ReceiveExplosionDmg(Explosion* explosion) { return false; };
diff --git a/server/gameserver/room.cc b/server/gameserver/room.cc
index 4a1015d..ad92918 100644
--- a/server/gameserver/room.cc
+++ b/server/gameserver/room.cc
@@ -1400,6 +1400,7 @@ void Room::UpdateGasJump()
             InitAirRaid();
         }
         ClearPostBattleAutoFreeList();
+        OnBattleStart();
     }
 }
 
@@ -4031,3 +4032,8 @@ void Room::ClearPostBattleAutoFreeList()
         }
     }
 }
+
+void Room::OnBattleStart()
+{
+
+}
diff --git a/server/gameserver/room.h b/server/gameserver/room.h
index 307acd3..e77b849 100644
--- a/server/gameserver/room.h
+++ b/server/gameserver/room.h
@@ -270,6 +270,7 @@ private:
     void InitAndroidAI();
     void ForwardGasRing(int n);
     void InternalRemoveObjectLater(Entity* entity, a8::XTimerAttacher& entity_xtimer_attacher);
+    void OnBattleStart();
     void ClearPostBattleAutoFreeList();
 
     #ifdef DEBUG
diff --git a/server/tools/protobuild/metatable.proto b/server/tools/protobuild/metatable.proto
index 9257685..ad9e69e 100755
--- a/server/tools/protobuild/metatable.proto
+++ b/server/tools/protobuild/metatable.proto
@@ -266,6 +266,7 @@ message Buff
     optional int32 dead_valid = 23;
     optional int32 buff_interval = 24;
     optional string tag = 25;
+    optional int32 post_battle_valid = 26;
 }
 
 message Drop