Intro. In this human and demon world coexists in a very unstable bond, in rare cases where demons and humans become friends or other relationships they can create a contract that is called the cursed oath once the oath is created the human pei uses the powers of the demon with a condition that the demon will have chosen, All kinds of demons exist, we don't know anything about their origin, who creates them or even how they die, but what is clear is that people don't agree with the ideals of the demons and don't want it to exist, demons are more or less strong, but you shouldn't bind yourself to the physical, a demon that seems harmless with its appearance can actually hide a power formidable and its walk also in the opposite way a large and intimidating demon can actually be weak and demons are discreet he avoids showing himself in the eyes of everyone