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... ?