Addition of getMainDamageDealer method.

L2J_Mobius_Classic_Interlude/java/org/l2jmobius/gameserver/model/actor/Attackable.java

@@ -726,6 +726,27 @@ public class Attackable extends Npc
 		getAttackByList().add(new WeakReference<>(creature));
 	}
 	
+	public Creature getMainDamageDealer()
+	{
+		if (_aggroList.isEmpty())
+		{
+			return null;
+		}
+		
+		int damage = 0;
+		Creature damageDealer = null;
+		for (AggroInfo info : _aggroList.values())
+		{
+			if ((info != null) && (info.getDamage() > damage) && Util.checkIfInRange(Config.ALT_PARTY_RANGE, this, info.getAttacker(), true))
+			{
+				damage = info.getDamage();
+				damageDealer = info.getAttacker();
+			}
+		}
+		
+		return damageDealer;
+	}
+	
 	/**
 	 * Add damage and hate to the attacker AggroInfo of the Attackable _aggroList.
 	 * @param attacker The Creature that gave damages to this Attackable

L2J_Mobius_Classic_Interlude/java/org/l2jmobius/gameserver/model/actor/Creature.java

@@ -1692,7 +1692,9 @@ public abstract class Creature extends WorldObject implements ISkillsHolder, IDe
 		abortAttack();
 		abortCast();
 		
-		calculateRewards(killer);
+		// Calculate rewards for main damage dealer.
+		final Creature mainDamageDealer = isMonster() ? ((MonsterInstance) this).getMainDamageDealer() : null;
+		calculateRewards(mainDamageDealer != null ? mainDamageDealer : killer);
 		
 		// Set target to null and cancel Attack or Cast
 		setTarget(null);