General

ooo nice man. I would've put in my vote for Dr. Robotnik, but Kane just seems more vile. On it's current trajectory in the C&C universe Nod's Tiberium experiments would basically make the world uninhabitable. That's basically the end of all life. Dr. Robotnik might be nefarious for polluting and destroying the environment, trying to kill, enslave, or robotcize everyone, but at least the freedom fighters have a chance for survival. His war isn't soo violent that all of Mobius has become uninhabitable. That and in the SonicVerse there are a lot of different factions that could potentially challenge Robotnik.

Oh yea, here's another one (Again from the mind of Stephen King) Sarah Tidwell. She was a wraith in Bag of Bones, that has been possessed by a demon known only as an Outsider.

She was just downright terrifying.