How powerful is he?

lol

Its funny in the behind the scenes when Ian asks Peter Jackson why he just doesnt zap away the bad guys

You can really see that he didnt enjoy that role, he just seems so bored

weaker than the witch king

Also he exorcised Saruman from Theoden, called the moth/eagles for help, made a dank smoke ship, oh and he came back from the fucking dead more powerful than before.