Rin Okumura, the fire-wielding son of Satan training to become an exorcist at True Cross Academy, and his scholarly twin Yukio anchor this spin-off light novel series set inside the world of Blue Exorcist. Headmaster Mephisto Pheles, herbalist Shiemi Moriyama, and instructor Shura Kirigakure recur across its side stories, which run alongside the main manga rather than continuing its central plot. Individual volumes carry their own subtitles, such as Weekend Hero and Home Sweet Home, each following the Exwire class through self-contained cases outside the main series' arcs.