Ryooka Adenine, declared a failure of a Demon Master at the age of 8 by her prestigious family line.
Found to be unable to form a contract between her and a demon despite having the ability to see them, she was turned into the black sheep of the family.
8 years later enter an intelligent, mummy like demon named by Ryook as: Zero.
"You have zero power, take up zero space, and have zero uses except to annoy the shit out of me."
