I started an egrimm campaign with the mixu cheat and it's quite fun.

It's a cross between a tzeentch and vilitch campaign. The mortal units replace blue/pink horros (but you can get horrors in a beastmen dread style menu).

Nothing OP so far except the mortal units do have the warshrine trait that gives infinite winds when things die near them.

You can confed kairos, changeling and vilitch which should be fun.