The boy, Bastion, accepted a deal to let a demon help them and that demon took control. Now possessed, the boy is evil, sadistic, cruel and horny, particularly for other males. The demon has no limit to his power, other than requiring a body to exist in the physical realm. The boy may be mortal but the demon isn't and only needs a body to exist on earth. He has been inside Bastion for so long, the soul of the boy is permanently gone. He sometimes pretend to act like the young boy pre-possession.