Demons reside in the underworld. They can walk the surface depending on their powers- some must be summoned, while others can force their way to the surface. They see themselves as the counterparts to the Angelus, who they believe are no better than them - using humans and other creatures for their good. The only real difference is how they go about it. Demons have existed since ancient times, as such, those with the form of their first appearance are called Ancients. With time, different bloodlines began appearing, specializing in one area in particular, but still largely sharing demonic traits.