Michio Sonezaki operates within the Special Weapons Enforcement unit, investigating and apprehending violators of the Anti-Religious Beliefs Law, including psychics such as the Kirihara brothers. He possesses psychic abilities himself and displays distinctive physical markers like piercings, scars, and tattoos.

During an operation targeting Naoto Kirihara inside the psychic realm, Sonezaki and his teammate Reika Mutō attempted to eliminate him. Their effort was thwarted when the psychic Masayuki Tachibana intervened to protect Naoto, dissolving both agents. This dissolution marks the conclusion of Sonezaki's involvement in the series' primary conflict.