Natsuhiko Kyōgoku is a Japanese mystery writer, graphic designer, art director, and yōkai researcher, born on March 26, 1963, in Otaru, Hokkaido. Before establishing himself as a novelist, he attended the Kuwasawa Design School and worked in the advertising and design industry, eventually founding his own design company. This background in visual arts has significantly influenced his approach to book design, as he personally oversees the covers, layouts, and typography of his publications to ensure they reflect the themes of the stories.

Kyōgoku made his literary debut in 1994 with the novel The Summer of the Ubume, published by Kodansha. This work marked the beginning of the Kyōgokudō series, also known as the Hyakki Yagyō series. The series is known for its substantial length and dense narratives that blend honkaku mystery—a style focused on logical puzzle-solving—with elements of Japanese folklore. A recurring feature of these stories is the character Akihiko Chuzenji, a bookseller and onmyōji who solves crimes through a method called tsukimono-otoshi, or exorcism. Rather than depicting supernatural events as literal, the narrative uses yōkai as metaphors to unravel the psychological motives of the characters. Kyōgoku has stated that he considers yōkai folklore a form of sublimation for human emotions.

Several of his novel series have been adapted into anime. The Mononoke Lecture Logs of Chuzenji-sensei is an anime television series based on a manga by Aki Shimizu, which itself is derived from Kyōgoku's Rozen Kreuz Series novels. The anime adaptation aired from April to June 2025 and was produced by studio 100studio. Additionally, the second novel in his Kyōgokudō series, Mōryō no Hako, which won the Mystery Writers of Japan Award in 1996, was adapted into an anime television series that began airing in October 2008. His novel Kosetsu Hyaku Monogatari, part of a series of Edo-period ghost stories, has also been adapted into anime, as has his science fiction mystery novel Loups-Garous, which was released as an anime feature film.

Kyōgoku is recognized as a significant figure in Japanese literature and popular culture. He is a member of the Mystery Writers of Japan and the Honkaku Mystery Writers Club of Japan. His work has received numerous prestigious awards, including the Yamamoto Shūgorō Prize in 2003 and the Naoki Prize in 2004 for Nochi no Kōsetsu Hyaku Monogatari. Beyond writing, he is an active yōkai researcher and a self-proclaimed disciple of influential manga artist Shigeru Mizuki. He serves as a councilor of the World Yōkai Association and was inaugurated as Director of the Printing Museum in Tokyo in April 2025. In addition to his literary and design work, he has contributed to anime as a voice actor for the series The Box of Goblins and as a screenwriter for the television series Horror Picture Book Season 7.