Shiki Ichinose s blood is Oni, and his father s is Momotarou. Normally, those with Momotarou blood hunt the Oni but Shiki s father refused to kill him as an infant. Instead, he adopted Shiki and raised him despite the rebellious attitude and dangerous temper that comes with Oni blood. When a member of the Momotarou Agency kills Shiki s father, he vows to avenge hm. But as Shiki hones his abilities and learns to control his Oni blood, will he be strong enough to survive the dangers waiting for him...?