Having the Demon Rat be allowed to spawn in breaks the nether, it crashes the game every time. I know apparently there is some type of conflict between Valhelsia Structures and Rats, but I've removed Valhesia structures so I can turn on the Demon Rats, they still crash the nether

Having looked around here I see this is a very old issue, and not due to Valhesia Structures.

wish the author would at least have their spawn turned off by default so i didnt had to spend hours checking mod by mod what would crash my nether

see #671