Epiales, a.k.a Melas Oneiros (black dream), is god or spirit of nightmares in the Ancient Greek religion.
Appearance: A black winged youth
Lore: Epiales attacks his victims while they sleep, producing terrifying nightmares.
Powers: Epiales can invoke great feelings of terror and fright, as well as produce the classic physical symptoms in the body associated with such states.
Defense Against Epiales: Unknown. However, coming to term with one's fears and reassuring one's self that it's just a dream may be of help.