Vukodlak of Vampire: The Masquerade - Redemption. Using his fearsome psychic powers and horrible minions, he likes to violate (in various ways, mostly moral and such I imagine) virtuous young women, turn them into his servants, make them do evil things themselves, etc. etc. His previous servant, he pretty much abandoned, and the one he converts in the game, he toys with in every evil way imaginable for about eight hundred years... making her lure innocents into his cathedral of flesh to be tortured and defiled before being melded into the very walls of the place, possibly still alive in some sense.
...I have difficulty imagining anyone meaner than that creep...