Katsumi Komura, affectionately called "Katchan" by the protagonist Wataru Mitani, appears solely in the *Brave Story* film adaptation. He is identified as Wataru Mitani's best friend within the story's real-world setting. This character is exclusive to the film and does not appear in other *Brave Story* media, including the novel, manga, video games, or any other adaptations, seasons, movies, OVAs, or spin-offs.