A DC Comics character created by Garth Ennis who inhabits Gotham City. Due to an attack by a strange alien, he can read people's minds and has X-ray vision, so he's veritably unsurprisable. He makes a living by killing super-powered individuals who fail to be good.
He's been known to work with Etrigan, make a mockery of Batman and Green Lantern, and claims to have seen Wonder Woman naked.
He is unabashedly Irish, much like his creator.