Individuals with Momotarou and Oni blood coursing through their veins maintain a longstanding rivalry. The Oni are careless, rash, and disorderly, while the Momotarou protect the human world from the uncontrollable Oni. Shiki Ichinose is a reckless and irresponsible teenager, aware of his defiance and even proud of his expulsion from school. Despite Shiki's rebellious attitude, his foster father, Tsuyoshi, cares about him deeply. Tsuyoshi's selfless love is soon shown in an explosive incident when a Momotarou barges in looking for Shiki. As a Momotarou himself, Tsuyoshi has been hiding Shiki for years and keeping his Oni origins a secret even from him. As he gives up his life to save Shiki and confesses everything in his dying breath, Shiki's Oni blood awakens for the first time, transfor