Akihiko Chūzenji runs Kyougokudou, an antique bookshop, and works part-time as a Shinto priest performing exorcism-like practices, yet he rejects supernatural beliefs and treats each case as a psychological puzzle demanding rational solutions. He uses a method called Tsukimono-Otoshi, which dismantles emotional or psychological obsessions by linking them to yōkai folklore and exposing hidden truths. His expertise encompasses extensive knowledge of Japanese mythology, obscure subjects, and entities such as mouryou. During World War II, he served in a medical research unit alongside Kōshirō Mimasaka, conducting experimental procedures that involved sustaining biological functions through mechanical replacements. Before establishing his bookstore, he worked as a literature teacher at a Tokyo high school in 1948, where he guided student Kanna Kusakabe in investigating supernatural school phenomena, debunking legends like “Red Paper, Blue Paper” through logical deduction. In the 1952 dismemberment case, he deduced the perpetrator by analyzing a fiction manuscript, exposed a fraudulent cult leader’s schemes, and reconstructed the full sequence of events, including medical experimentation that mechanically sustained victims’ heads and the familial secrets driving the crimes. His relationships include his younger sister Atsuko, a reporter and editor, as well as close friends and collaborators such as crime writer Tatsumi Sekiguchi, detective Shutarō Kiba, and investigator Reijirō Enokizu. Throughout his appearances, he maintains a calm, analytical demeanor, functioning as an observer and analyst who pieces together solutions through deductive reasoning, often communicating through elaborate monologues that strategically withhold or reveal information.