The second Azazel on the list, this demon is one that you've likely forgotten about, but who certainly deserves its place here. Appearing in the 1998 supernatural thriller "Fallen," this creature is first seen possessing a man named Edgar Reese (Elias Koteas), who has been accused of killing countless people. Of course, the demon admits to his murders but explains to Detective John Hobbes (Denzel Washington) that he'll be back again. After his vessel is killed, Azazel finds a new host and soon makes Hobbes' life a living hell, framing him for a new series of copycat murders.

Like his "Supernatural" counterpart, the Azazel in "Fallen" isn't traditionally terrifying, but it's their actions that make them particularly noteworthy. For starters, they're a serial killer. Demons like Valak may haunt to kill, but this version of Azazel has no problem slaughtering his enemies right then and there. In fact, as Hobbes learns, the only way to stop a demon like this (aside from hiding out in a church) is by killing yourself in the middle of nowhere where the demon can't find a new host to latch onto. Unfortunately, Hobbes' plan fails, and at the end of "Fallen," Azazel strolls off in the form of a black cat to the tune of "Sympathy for the Devil."

Both demons and serial killers are bad enough on their own, but when you add the two together, they become nearly unstoppable. Hobbes almost got there, but Azazel is out in the wind — and who knows who he'll strike next time around.