The conflict between Oni and Momotarou bloodlines deepens as Shiki Ichinose ventures toward Nikko Kegon Falls, where ancient powers converge and new secrets about his lineage await. Having accepted his Oni heritage, Shiki now grapples with the weight of his dual nature while the fragile truce between the agencies begins to fracture. The falls themselves hold significance beyond geography: they're a nexus point where the boundary between the human world and something far older grows thin. Competing factions close in, each believing Shiki holds the key to shifting the balance of power in their favor. As mysteries surrounding his past unfold, Shiki must navigate betrayals within both agencies while learning to harness abilities he's only begun to understand. The road to self-discovery becomes a dangerous game of survival, where trusting the wrong person could mean the difference between salvation and destruction. This arc intensifies the supernatural conflict and forces Shiki to confront whether he can forge his own path or if destiny has already written his fate in blood.