Yeah. I still need that iconic villain for him. For his origin story it turns out to be his best friend. But I need my Joker, My Lex Luthor.

I need a villain who is cunning and cruel. One who is driven and a little on the bat shit crazy side.

It is a used thread amongst heroes.  Doctor Doom and Reed Richards comes to mind immediately.  Both brilliant and one bat shit crazy.  More likely however is that great good attracts great evil.  It's like they almost need each other.  Sometimes evil is just a point of view.  Ask Jean Valjean.  You have a story in your head.  Rough it out and then do some casting for the part.