Following Shirosaki's advice, Gero continues his search for a wife. He is asked by Arashiyama Kimie, a "hamster user," to protect her from "assassin hunters" because, despite being a "user," she is not good at combat. Overwhelmed by her enthusiasm, Gero agrees. Shirosaki seems hopeful that Gero and Arashiyama might get along surprisingly well since they are both "users." Later, Gero and Shirosaki are taken by Arashiyama to a gathering of collateral branches of the "beast tamers." There, Gero confronts Nakagawa Momoichi, an assassin hunter and a mutant ordinary person with combat abilities that surpass even top-class assassins. What exactly is his objective...?

As Arashiyama and Gero head towards the enemy's headquarters together, Gero proposes that they defeat the "Beast Tamer" together. While planning their strategy in a cave where they take refuge for the night, the two grow closer, but the atmosphere changes abruptly when Toshiro appears. Toshiro then hurls words that fuel Gero's murderous intent and takes Arashiyama away. As Gero pursues them, he is attacked by 100 of the "Beast Tamer's" associates, strengthened by Toshiro's "mixed blood." Outnumbered and exhausted, Gero is then confronted by "reinforcements" arranged by Shirosaki…