Names, Names, Names..

I know that I've asked a question like this before, but I need help with a character name. This time, it's a villain; I'm shaking it up a little!

So this guy is sneaky, clever, and when he kills, he finds a way to make you suffer slowly. He used to be one of the good ones, but turned traitor and became an evil villan, changing his name to match his new, now sinister self.

Any help would be appreciated. Any names associated with darkness, death, treachery, evil, or sneakyness would be good, but I kinda want a normal first name, with an obvious last name, like Jack Frost or something.

Thanks!!