Well, if we're basing our powers on our personalities, I'd be Sarcasm Man!
I have the power to make anything untrue by sarcastically agreeing with it.
"Oh, suuuure, you're going to murder me in cold blood rather than placing me into an absurdly overdesigned deathtrap. Riiight."

Noone would ever be able to discover my secret identity and confront me with it! "Yes. That's right. I am Sarcasm Man. Well done."


Now, I would like to inform all those who declared themselves to be villains that they aren't. This is why.