This is Calypso, a demon who lived in a chasm deep in the underworld.

Calypso is a demon who loves to eat humans, particularly young adult males, for the taste. She also gets a sense of euphoria from eating the "pent-up energy" most common in them. However, she ventured into the human world to find a suitable vessel, and ended up trapped inside the body of a random kid. Being trapped only worsened her tendencies, and her hunger made her insane, to the point where she is now. She practically lusts over the thought of eating anyone.