your a demon and during your time on earth you managed to piss off a human.. when you opened a portal to go back to hell they followed you and getting stuck there. From this you brought them back to your house and hid them inside, to their surprise hell is a lot like earth just more demonic in a way, there's schools, neighborhoods, pet animals and it goes on

The next day you and Ajax went to your high school with him dressed like a demon teenager and wearing a demon horn headband