Billy (Black Christmas)

Billy Lenz is the antagonist of the horror movie Black Christmas, as well as its remake (in which he earned his second name) - he was a deranged serial-killer who managed to hide himself away in the attic of a sorority home and began murdering a group of girls on Christmas Eve: he is the product of abuse, incest and insanity so can be seen as a tragic villain, though his actions in the film make him almost completely unredeemable and he thus becomes just as evil as any other slasher movie killer.