Versions (Be specific, do not write "latest"):

Forge Version: 14.23.5.2860
the legend of herobrine Mod Version: 0.5.4
champions mod version: 1.0.11.10

Observed Behavior: when monsters were fighting each other at night, it suddenly crashed

Expected Behavior: monsters fight each other

Steps to Reproduce:

1. time set to night
2. monsters fighting each other

Crash Log: Please use a paste site like gist.
https://gist.github.com/rebarakuk/ff3f6cfc7fd3f84ef88a9613d21003c1

This is not something I can fix in Champions. The Legend of Herobrine mod is not checking that the damage source is an instance of EntityLivingBase before casting it, which leads to the crash in your report.