Details and crash log are here:
klikli-dev/occultism#1029

@uhloin I just noticed that you are using neoforge - but 1.13 is forge only (see tags on curseforge), which would explain the crash.
1.12 has a neoforge version it seems

Hm?

Neoforge has a 1.13 version as well

https://www.curseforge.com/minecraft/mc-mods/smartbrainlib/files/4981374

1.13 Works fine

You're using Forge 1.13 on a Neoforge loader.

If you want to use NeoForge, use the NeoForge version. Forge broke brains in 1.20.1 and so they're no longer compatible between forge and neoforge

Thank you too. There note on the NeoForge site about compatibility for 1.20.1, so I always used Forge filter because of some mods haven't separate versions for NeoForge 1.20.1. Yours is first among I use. 1.13 for neoforge version works fine.

Thank you too. There note on the NeoForge site about compatibility for 1.20.1, so I always used Forge filter because of some mods haven't separate versions for NeoForge 1.20.1. Yours is first among I use. 1.13 for neoforge version works fine.

@uhloin this does not depend on the mod but rather on if forge broke any features of that mod and requires a custom version. Forge changed how brains work, so SBL is affected and needs two separate versions .. modders do not have it easy at times.

Sorry for sending you down a wrong path here, I got mislead by the same thing