WMG / Uninvited

The game-over skull and the Demons are avatars of the same entity
It's implied that Dracan released something which single-handedly turned the mansion into a hellhouse, with dominion over all the living and undead who remain there for a prolonged time. In the endgame, the demon which tries to possess your sister is determined to be the "source" of all the evil things in the house, but in the Ruby game-over, the blood-red skull which appears in the death screens is described as "your new master." Surely there is such a connection between these two figures.