Saburō Kidō leads a group of bullies targeting Hosuke Sharaku and Chiyoko Wato at their school. He orchestrates relentless teasing and physical harassment against Sharaku, mocking his childish behavior and perceived clumsiness, positioning himself as an early source of conflict.

A pivotal escalation occurs when one of Kidō's followers tears off Sharaku's X-shaped bandage, unleashing Sharaku's transformed superpowered and malevolent state. In retaliation, Sharaku deploys a device that liquefies human brains, testing it on Kidō and his group. The machine renders them docile and vacant-minded, leading to their permanent disappearance from the manga's school setting.

Within the anime continuity, the device's effects prove temporary, lasting only three days and inducing amnesia about the incident. Kidō and his followers return to school as recurring characters, continuing to appear throughout the series despite diminished antagonistic roles after the initial story arc.