Same error has happened three times between two members on my server. Two of the incidents were immediately following them killing an aggressive mob (zombie/skelly). The last one was when the member was killed by a mob. Identical crash logs in all scenarios.

---- Minecraft Crash Report ----

WARNING: coremods are present:
Do not report to Forge! Remove FoamFixAPI (or replace with FoamFixAPI-Lawful) and try again. (foamfix-0.9.4-1.12.2-anarchy.jar)
CTMCorePlugin (CTM-MC1.12-0.2.3.12.jar)
HammerCoreCore (HammerCore-1.12.2-1.9.6.8.jar)
CorePlugin (ForgeEndertech-1.12.1-4.3.1.0-build.0071.jar)
AstralCore (astralsorcery-1.12.2-1.8.5.jar)
EnderCorePlugin (EnderCore-1.12.2-0.5.12.jar)
Plugin (NotEnoughIDs-1.5.4.2.jar)
MicdoodlePlugin (MicdoodleCore-1.12.2-4.0.1.144.jar)
LoadingPlugin (AdChimneys-1.12.1-3.2.1.2-build.0079.jar)
IELoadingPlugin (ImmersiveEngineering-0.12-78-core.jar)
ShetiPhian-ASM (shetiphiancore-1.12.0-3.5.6.jar)
Inventory Tweaks Coremod (InventoryTweaks-1.63.jar)
BCModPlugin (backpacks+1.12.2+-+3.4.3.jar)
ModFixLC (ModFix-1.12.2-1.0.0.1.jar)
ForgelinPlugin (Forgelin-1.6.0.jar)
TransformerLoader (OpenComputers-MC1.12.1-1.7.1.43.jar)
LoadingPlugin (Quark-r1.4-122.jar)
MDECore-Core (mdecore-1.12-1.0.jar)
Contact their authors BEFORE contacting forge

// My bad.

Time: 2/27/18 10:25 PM
Description: Unexpected error

java.lang.NullPointerException: Unexpected error
at me.ichun.mods.morph.client.core.EventHandlerClient.onClientTick(EventHandlerClient.java:836)
at net.minecraftforge.fml.common.eventhandler.ASMEventHandler_1656_EventHandlerClient_onClientTick_ClientTickEvent.invoke(.dynamic)
at net.minecraftforge.fml.common.eventhandler.ASMEventHandler.invoke(ASMEventHandler.java:90)
at net.minecraftforge.fml.common.eventhandler.EventBus.post(EventBus.java:179)
at net.minecraftforge.fml.common.FMLCommonHandler.onPostClientTick(FMLCommonHandler.java:348)
at net.minecraft.client.Minecraft.func_71407_l(Minecraft.java:1909)
at net.minecraft.client.Minecraft.func_71411_J(Minecraft.java:1096)
at net.minecraft.client.Minecraft.func_99999_d(Minecraft.java:397)
at net.minecraft.client.main.Main.main(SourceFile:123)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at net.minecraft.launchwrapper.Launch.launch(Launch.java:135)
at net.minecraft.launchwrapper.Launch.main(Launch.java:28)

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

-- Head --
Thread: Client thread
Stacktrace:
at me.ichun.mods.morph.client.core.EventHandlerClient.onClientTick(EventHandlerClient.java:836)
at net.minecraftforge.fml.common.eventhandler.ASMEventHandler_1656_EventHandlerClient_onClientTick_ClientTickEvent.invoke(.dynamic)
at net.minecraftforge.fml.common.eventhandler.ASMEventHandler.invoke(ASMEventHandler.java:90)
at net.minecraftforge.fml.common.eventhandler.EventBus.post(EventBus.java:179)
at net.minecraftforge.fml.common.FMLCommonHandler.onPostClientTick(FMLCommonHandler.java:348)

-- Affected level --
Details:
Level name: MpServer
All players: 1 total; [GCEntityClientPlayerMP['[redacted]'/7330, l='MpServer', x=157.50, y=73.00, z=-19.50]]
Chunk stats: MultiplayerChunkCache: 441, 441
Level seed: 0
Level generator: ID 06 - BIOMESOP, ver 0. Features enabled: false
Level generator options:
Level spawn location: World: (160,64,-16), Chunk: (at 0,4,0 in 10,-1; contains blocks 160,0,-16 to 175,255,-1), Region: (0,-1; contains chunks 0,-32 to 31,-1, blocks 0,0,-512 to 511,255,-1)
Level time: 113445 game time, 124255 day time
Level dimension: 0
Level storage version: 0x00000 - Unknown?
Level weather: Rain time: 0 (now: false), thunder time: 0 (now: false)
Level game mode: Game mode: survival (ID 0). Hardcore: false. Cheats: false

[Removed entities for brevity]

Server brand: fml,forge
Server type: Non-integrated multiplayer server

Stacktrace:
at net.minecraft.client.multiplayer.WorldClient.func_72914_a(WorldClient.java:420)
at net.minecraft.client.Minecraft.func_71396_d(Minecraft.java:2748)
at net.minecraft.client.Minecraft.func_99999_d(Minecraft.java:426)
at net.minecraft.client.main.Main.main(SourceFile:123)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at net.minecraft.launchwrapper.Launch.launch(Launch.java:135)
at net.minecraft.launchwrapper.Launch.main(Launch.java:28)

Which Forge Version are you using. For me, it crashes on load

Forge 2620, the latest version when I pushed my update yesterday

Forge 2623:

net.minecraftforge.fml.common.LoaderExceptionModCrash: Caught exception from iChunUtil (ichunutil)
Caused by: java.lang.NoClassDefFoundError: net/minecraft/client/resources/I18n
at net.minecraftforge.fml.common.versioning.Restriction.toStringFriendly(Restriction.java:227)
at net.minecraftforge.fml.common.versioning.VersionRange.toStringFriendly(VersionRange.java:500)

I'll see if i can fork this repo and find a fix

This should be fixed on 7.1.3 when it's released.