The mod seemed to do fine with the others I had up until the point when my friend spawned a guard villager and it attacked some drowned sitting in the water during the day, which crashed my game crash. I removed all other mods except guard villagers and epic fight mod and my game only crashed when they attack drowned in the water during the day.

---- Minecraft Crash Report ----
// Who set us up the TNT?

Time: 7/16/21 7:56 AM
Description: Ticking entity

java.lang.RuntimeException: Attempted to load class maninhouse/epicfight/client/capabilites/entity/ClientPlayerData for invalid dist DEDICATED_SERVER
at net.minecraftforge.fml.loading.RuntimeDistCleaner.processClassWithFlags(RuntimeDistCleaner.java:71) ~[forge-1.16.5-36.1.35.jar:36.1] {}
at cpw.mods.modlauncher.LaunchPluginHandler.offerClassNodeToPlugins(LaunchPluginHandler.java:85) ~[modlauncher-8.0.9.jar:?] {}
at cpw.mods.modlauncher.ClassTransformer.transform(ClassTransformer.java:120) ~[modlauncher-8.0.9.jar:?] {}
at cpw.mods.modlauncher.TransformingClassLoader$DelegatedClassLoader.findClass(TransformingClassLoader.java:265) ~[modlauncher-8.0.9.jar:?] {}
at cpw.mods.modlauncher.TransformingClassLoader.loadClass(TransformingClassLoader.java:136) ~[modlauncher-8.0.9.jar:?] {re:classloading}
at cpw.mods.modlauncher.TransformingClassLoader.loadClass(TransformingClassLoader.java:98) ~[modlauncher-8.0.9.jar:?] {re:classloading}
at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.8.0_261] {}
at maninhouse.epicfight.animation.types.BasicAttackAnimation.getCoordVector(BasicAttackAnimation.java:61) ~[epicfight:1.0] {re:classloading}
at maninhouse.epicfight.animation.types.ActionAnimation.move(ActionAnimation.java:92) ~[epicfight:1.0] {re:classloading}
at maninhouse.epicfight.animation.types.ActionAnimation.updateOnLinkAnimation(ActionAnimation.java:75) ~[epicfight:1.0] {re:classloading}
at maninhouse.epicfight.animation.types.LinkAnimation.onUpdate(LinkAnimation.java:12) ~[epicfight:1.0] {re:classloading}
at maninhouse.epicfight.animation.AnimatorServer.update(AnimatorServer.java:57) ~[epicfight:1.0] {re:classloading}
at maninhouse.epicfight.capabilities.entity.LivingData.update(LivingData.java:134) ~[epicfight:1.0] {re:classloading,pl:runtimedistcleaner:A}
at maninhouse.epicfight.events.EntityEvents.updateEvent(EntityEvents.java:101) ~[epicfight:1.0] {re:classloading}
at net.minecraftforge.eventbus.ASMEventHandler_22_EntityEvents_updateEvent_LivingUpdateEvent.invoke(.dynamic) ~[?:?] {}
at net.minecraftforge.eventbus.ASMEventHandler.invoke(ASMEventHandler.java:85) ~[eventbus-4.0.0.jar:?] {}
at net.minecraftforge.eventbus.EventBus.post(EventBus.java:302) ~[eventbus-4.0.0.jar:?] {}
at net.minecraftforge.eventbus.EventBus.post(EventBus.java:283) ~[eventbus-4.0.0.jar:?] {}
at net.minecraftforge.common.ForgeHooks.onLivingUpdate(ForgeHooks.java:339) ~[forge:?] {re:classloading}
at net.minecraft.entity.LivingEntity.func_70071_h_(LivingEntity.java:2112) ~[?:?] {re:classloading,pl:accesstransformer:B,pl:runtimedistcleaner:A,re:mixin,pl:accesstransformer:B,pl:runtimedistcleaner:A}
at net.minecraft.entity.MobEntity.func_70071_h_(MobEntity.java:300) ~[?:?] {re:classloading,pl:accesstransformer:B,pl:runtimedistcleaner:A,re:mixin,pl:accesstransformer:B,pl:runtimedistcleaner:A}
at net.minecraft.entity.monster.ZombieEntity.func_70071_h_(ZombieEntity.java:205) ~[?:?] {re:mixin,re:classloading,pl:mixin:APP:guardvillagers.mixins.json:ZombieEntityMixin,pl:mixin:A}
at net.minecraft.world.server.ServerWorld.func_217479_a(ServerWorld.java:611) ~[?:?] {re:classloading,pl:runtimedistcleaner:A,re:mixin,pl:runtimedistcleaner:A}
at net.minecraft.world.World.func_217390_a(World.java:554) ~[?:?] {re:classloading,pl:accesstransformer:B,pl:runtimedistcleaner:A,re:mixin,pl:accesstransformer:B,pl:runtimedistcleaner:A}
at net.minecraft.world.server.ServerWorld.func_72835_b(ServerWorld.java:404) ~[?:?] {re:classloading,pl:runtimedistcleaner:A,re:mixin,pl:runtimedistcleaner:A}
at net.minecraft.server.MinecraftServer.func_71190_q(MinecraftServer.java:851) ~[?:?] {re:classloading,pl:accesstransformer:B,pl:runtimedistcleaner:A}
at net.minecraft.server.dedicated.DedicatedServer.func_71190_q(DedicatedServer.java:291) ~[?:?] {re:classloading,pl:accesstransformer:B}
at net.minecraft.server.MinecraftServer.func_71217_p(MinecraftServer.java:787) ~[?:?] {re:classloading,pl:accesstransformer:B,pl:runtimedistcleaner:A}
at net.minecraft.server.MinecraftServer.func_240802_v_(MinecraftServer.java:642) ~[?:?] {re:classloading,pl:accesstransformer:B,pl:runtimedistcleaner:A}
at net.minecraft.server.MinecraftServer.func_240783_a_(MinecraftServer.java:232) ~[?:?] {re:classloading,pl:accesstransformer:B,pl:runtimedistcleaner:A}
at java.lang.Thread.run(Unknown Source) [?:1.8.0_261] {}

A detailed walkthrough of the error, its code path and all known details is as follows:

-- Head --
Thread: Server thread
Stacktrace:
at net.minecraftforge.fml.loading.RuntimeDistCleaner.processClassWithFlags(RuntimeDistCleaner.java:71) ~[forge-1.16.5-36.1.35.jar:36.1] {}
at cpw.mods.modlauncher.LaunchPluginHandler.offerClassNodeToPlugins(LaunchPluginHandler.java:85) ~[modlauncher-8.0.9.jar:?] {}
at cpw.mods.modlauncher.ClassTransformer.transform(ClassTransformer.java:120) ~[modlauncher-8.0.9.jar:?] {}
at cpw.mods.modlauncher.TransformingClassLoader$DelegatedClassLoader.findClass(TransformingClassLoader.java:265) ~[modlauncher-8.0.9.jar:?] {}
at cpw.mods.modlauncher.TransformingClassLoader.loadClass(TransformingClassLoader.java:136) ~[modlauncher-8.0.9.jar:?] {re:classloading}
at cpw.mods.modlauncher.TransformingClassLoader.loadClass(TransformingClassLoader.java:98) ~[modlauncher-8.0.9.jar:?] {re:classloading}
at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.8.0_261] {}
at maninhouse.epicfight.animation.types.BasicAttackAnimation.getCoordVector(BasicAttackAnimation.java:61) ~[epicfight:1.0] {re:classloading}
at maninhouse.epicfight.animation.types.ActionAnimation.move(ActionAnimation.java:92) ~[epicfight:1.0] {re:classloading}
at maninhouse.epicfight.animation.types.ActionAnimation.updateOnLinkAnimation(ActionAnimation.java:75) ~[epicfight:1.0] {re:classloading}
at maninhouse.epicfight.animation.types.LinkAnimation.onUpdate(LinkAnimation.java:12) ~[epicfight:1.0] {re:classloading}
at maninhouse.epicfight.animation.AnimatorServer.update(AnimatorServer.java:57) ~[epicfight:1.0] {re:classloading}
at maninhouse.epicfight.capabilities.entity.LivingData.update(LivingData.java:134) ~[epicfight:1.0] {re:classloading,pl:runtimedistcleaner:A}
at maninhouse.epicfight.events.EntityEvents.updateEvent(EntityEvents.java:101) ~[epicfight:1.0] {re:classloading}
at net.minecraftforge.eventbus.ASMEventHandler_22_EntityEvents_updateEvent_LivingUpdateEvent.invoke(.dynamic) ~[?:?] {}
at net.minecraftforge.eventbus.ASMEventHandler.invoke(ASMEventHandler.java:85) ~[eventbus-4.0.0.jar:?] {}
at net.minecraftforge.eventbus.EventBus.post(EventBus.java:302) ~[eventbus-4.0.0.jar:?] {}
at net.minecraftforge.eventbus.EventBus.post(EventBus.java:283) ~[eventbus-4.0.0.jar:?] {}
at net.minecraftforge.common.ForgeHooks.onLivingUpdate(ForgeHooks.java:339) ~[forge:?] {re:classloading}
at net.minecraft.entity.LivingEntity.func_70071_h_(LivingEntity.java:2112) ~[?:?] {re:classloading,pl:accesstransformer:B,pl:runtimedistcleaner:A,re:mixin,pl:accesstransformer:B,pl:runtimedistcleaner:A}
at net.minecraft.entity.MobEntity.func_70071_h_(MobEntity.java:300) ~[?:?] {re:classloading,pl:accesstransformer:B,pl:runtimedistcleaner:A,re:mixin,pl:accesstransformer:B,pl:runtimedistcleaner:A}
at net.minecraft.entity.monster.ZombieEntity.func_70071_h_(ZombieEntity.java:205) ~[?:?] {re:mixin,re:classloading,pl:mixin:APP:guardvillagers.mixins.json:ZombieEntityMixin,pl:mixin:A}
at net.minecraft.world.server.ServerWorld.func_217479_a(ServerWorld.java:611) ~[?:?] {re:classloading,pl:runtimedistcleaner:A,re:mixin,pl:runtimedistcleaner:A}
-- Entity being ticked --
Details:
Entity Type: minecraft:drowned (net.minecraft.entity.monster.DrownedEntity)
Entity ID: 76
Entity Name: Drowned
Entity's Exact location: 341.47, 62.00, -177.36
Entity's Block location: World: (341,62,-178), Chunk: (at 5,3,14 in 21,-12; contains blocks 336,0,-192 to 351,255,-177), Region: (0,-1; contains chunks 0,-32 to 31,-1, blocks 0,0,-512 to 511,255,-1)
Entity's Momentum: 0.00, -0.00, 0.00
Entity's Passengers: []
Entity's Vehicle: ERROR NullPointerException: null
Stacktrace:
at net.minecraft.world.World.func_217390_a(World.java:554) ~[?:?] {re:classloading,pl:accesstransformer:B,pl:runtimedistcleaner:A,re:mixin,pl:accesstransformer:B,pl:runtimedistcleaner:A}
at net.minecraft.world.server.ServerWorld.func_72835_b(ServerWorld.java:404) ~[?:?] {re:classloading,pl:runtimedistcleaner:A,re:mixin,pl:runtimedistcleaner:A}

-- Affected level --
Details:
All players: 0 total; []
Chunk stats: ServerChunkCache: 2136
Level dimension: minecraft:overworld
Level spawn location: World: (240,75,-192), Chunk: (at 0,4,0 in 15,-12; contains blocks 240,0,-192 to 255,255,-177), Region: (0,-1; contains chunks 0,-32 to 31,-1, blocks 0,0,-512 to 511,255,-1)
Level time: 1591 game time, 1591 day time
Level name: Dewie Land
Level game mode: Game mode: survival (ID 0). Hardcore: false. Cheats: false
Level weather: Rain time: 109422 (now: false), thunder time: 25515 (now: false)
Known server brands: forge
Level was modded: true
Level storage version: 0x04ABD - Anvil
Stacktrace:
at net.minecraft.server.MinecraftServer.func_71190_q(MinecraftServer.java:851) ~[?:?] {re:classloading,pl:accesstransformer:B,pl:runtimedistcleaner:A}
at net.minecraft.server.dedicated.DedicatedServer.func_71190_q(DedicatedServer.java:291) ~[?:?] {re:classloading,pl:accesstransformer:B}
at net.minecraft.server.MinecraftServer.func_71217_p(MinecraftServer.java:787) ~[?:?] {re:classloading,pl:accesstransformer:B,pl:runtimedistcleaner:A}
at net.minecraft.server.MinecraftServer.func_240802_v_(MinecraftServer.java:642) ~[?:?] {re:classloading,pl:accesstransformer:B,pl:runtimedistcleaner:A}
at net.minecraft.server.MinecraftServer.func_240783_a_(MinecraftServer.java:232) ~[?:?] {re:classloading,pl:accesstransformer:B,pl:runtimedistcleaner:A}
at java.lang.Thread.run(Unknown Source) [?:1.8.0_261] {}

-- System Details --
Details:
Minecraft Version: 1.16.5
Minecraft Version ID: 1.16.5
Operating System: Windows 10 (amd64) version 10.0
Java Version: 1.8.0_261, Oracle Corporation
Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
Memory: 5223903984 bytes (4981 MB) / 6294077440 bytes (6002 MB) up to 6294077440 bytes (6002 MB)
CPUs: 12
JVM Flags: 2 total; -Xmx6G -Xms6G
ModLauncher: 8.0.9+86+master.3cf110c
ModLauncher launch target: fmlserver
ModLauncher naming: srg
ModLauncher services:
/mixin-0.8.2.jar mixin PLUGINSERVICE
/eventbus-4.0.0.jar eventbus PLUGINSERVICE
/forge-1.16.5-36.1.35.jar object_holder_definalize PLUGINSERVICE
/forge-1.16.5-36.1.35.jar runtime_enum_extender PLUGINSERVICE
/accesstransformers-3.0.1.jar accesstransformer PLUGINSERVICE
/forge-1.16.5-36.1.35.jar capability_inject_definalize PLUGINSERVICE
/forge-1.16.5-36.1.35.jar runtimedistcleaner PLUGINSERVICE
/mixin-0.8.2.jar mixin TRANSFORMATIONSERVICE
/forge-1.16.5-36.1.35.jar fml TRANSFORMATIONSERVICE
FML: 36.1
Forge: net.minecraftforge:36.1.35
FML Language Providers:
[email protected]
minecraft@1
Mod List:
forge-1.16.5-36.1.35-server.jar |Minecraft |minecraft |1.16.5 |DONE |Manifest: NOSIGNATURE
forge-1.16.5-36.1.35-universal.jar |Forge |forge |36.1.35 |DONE |Manifest: 22:af:21:d8:19:82:7f:93:94:fe:2b:ac:b7:e4:41:57:68:39:87:b1:a7:5c:c6:44:f9:25:74:21:14:f5:0d:90
guardvillagers-1.16.5.1.2.4.jar |Guard Villagers |guardvillagers |1.2.4 |DONE |Manifest: NOSIGNATURE
EpicFightMod-1.16.5-4.1.5.jar |Epic Fight Mod |epicfight |4.1.5 |DONE |Manifest: NOSIGNATURE
Crash Report UUID: cab1f99c-cc1a-4930-ae68-7064f7065a58
Player Count: 0 / 15; []
Data Packs: vanilla, mod:forge, mod:guardvillagers, mod:epicfight
Is Modded: Definitely; Server brand changed to 'forge'
Type: Dedicated Server (map_server.txt)

Try this again when new update is released. thanks.