Hello! I'm running a campain, where one of my NPC's has multiple personalities. Ones evil and needs to die. The other is completely oblivious to the crimes of the other, and is innocent of all guilt...but stuck in the same body.

They want to try to separate them, and I'd like to allow that, but need a way to do it.

Any suggestions would be great! I assume I'll have to Homebrew it but if there's actual rules covering this that would be great!

You'll definitely have to house rule it.

House ruled it and now they got a cool artifact with a ghost in it sooooo that's nifty.