[02:19:43] [Server thread/ERROR]: Could not pass event EntityDamageByEntityEvent to LeaderMobs v1.4
org.bukkit.event.EventException: null
at org.bukkit.plugin.EventExecutor$2.execute(EventExecutor.java:72) ~[server.jar:git-Paper-1618]
at co.aikar.timings.TimedEventExecutor.execute(TimedEventExecutor.java:78) ~[server.jar:git-Paper-1618]
at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62) ~[server.jar:git-Paper-1618]
at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:513) ~[server.jar:git-Paper-1618]
at org.bukkit.craftbukkit.v1_12_R1.event.CraftEventFactory.callEvent(CraftEventFactory.java:94) ~[server.jar:git-Paper-1618]
at org.bukkit.craftbukkit.v1_12_R1.event.CraftEventFactory.callEntityDamageEvent(CraftEventFactory.java:620) ~[server.jar:git-Paper-1618]
at org.bukkit.craftbukkit.v1_12_R1.event.CraftEventFactory.handleEntityDamageEvent(CraftEventFactory.java:523) ~[server.jar:git-Paper-1618]
at org.bukkit.craftbukkit.v1_12_R1.event.CraftEventFactory.handleLivingEntityDamageEvent(CraftEventFactory.java:652) ~[server.jar:git-Paper-1618]
at net.minecraft.server.v1_12_R1.EntityLiving.damageEntity0(EntityLiving.java:1415) ~[server.jar:git-Paper-1618]
at net.minecraft.server.v1_12_R1.EntityLiving.damageEntity(EntityLiving.java:888) ~[server.jar:git-Paper-1618]
at net.minecraft.server.v1_12_R1.EntityMonster.damageEntity(EntityMonster.java:44) ~[server.jar:git-Paper-1618]
at net.minecraft.server.v1_12_R1.EntityHuman.attack(EntityHuman.java:1028) ~[server.jar:git-Paper-1618]
at net.minecraft.server.v1_12_R1.EntityPlayer.attack(EntityPlayer.java:1397) ~[server.jar:git-Paper-1618]
at net.minecraft.server.v1_12_R1.PlayerConnection.a(PlayerConnection.java:1724) ~[server.jar:git-Paper-1618]
at net.minecraft.server.v1_12_R1.PacketPlayInUseEntity.a(PacketPlayInUseEntity.java:49) ~[server.jar:git-Paper-1618]
at net.minecraft.server.v1_12_R1.PacketPlayInUseEntity.a(PacketPlayInUseEntity.java:6) ~[server.jar:git-Paper-1618]
at net.minecraft.server.v1_12_R1.PlayerConnectionUtils.lambda$ensureMainThread$0(PlayerConnectionUtils.java:14) ~[server.jar:git-Paper-1618]
at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source) ~[?:1.8.0_251]
at java.util.concurrent.FutureTask.run(Unknown Source) ~[?:1.8.0_251]
at net.minecraft.server.v1_12_R1.SystemUtils.a(SourceFile:46) ~[server.jar:git-Paper-1618]
at net.minecraft.server.v1_12_R1.MinecraftServer.D(MinecraftServer.java:850) ~[server.jar:git-Paper-1618]
at net.minecraft.server.v1_12_R1.DedicatedServer.D(DedicatedServer.java:423) ~[server.jar:git-Paper-1618]
at net.minecraft.server.v1_12_R1.MinecraftServer.C(MinecraftServer.java:774) ~[server.jar:git-Paper-1618]
at net.minecraft.server.v1_12_R1.MinecraftServer.run(MinecraftServer.java:666) ~[server.jar:git-Paper-1618]
at java.lang.Thread.run(Unknown Source) [?:1.8.0_251]
Caused by: java.lang.NullPointerException
at com.github.xhexed.leadermobs.handler.MobHandler.onPlayerDamage(MobHandler.java:77) ~[?:?]
at com.github.xhexed.leadermobs.listeners.LegacyMythicMobsListener.onDamage(LegacyMythicMobsListener.java:53) ~[?:?]
at com.destroystokyo.paper.event.executor.asm.generated.GeneratedEventExecutor499.execute(Unknown Source) ~[?:?]
at org.bukkit.plugin.EventExecutor$2.execute(EventExecutor.java:70) ~[server.jar:git-Paper-1618]
... 24 more