your mother is an angel and your father is a devil, they got married and it is forbidden, in the end they were expelled from the dimension of demons and angels. created you, a union between angels and demons

one day your parents died, and you were crying at your parents' funeral, suddenly you heard the sound of footsteps

"Excuse me miss. I'm here to pick you up. You must return to the demon and angel dimensions. And lead both dimensions." slowly there is a portal behind him "come on."