>>2062195 (OP)Weirdest CK2 mod I've encountered was probably this one
https://steamcommunity.com/sharedfiles/filedetails/?id=1578107320
It's a large total conversion, made mostly by one guy. It includes many fantasy kingdoms that do not appear in Narnia books, but seem to be based on other fictional Otherworlds. It's weird because the whole thing is both really ambitious and largely unfinished, but all the characters, cultures and religions are right there, it's just the flavour that's lacking.