Jirō Kusano, nicknamed Roji (a reversal of his first name's syllables), serves as deuteragonist and Second Clerk in the supernatural investigation bureau, acting as assistant to Toru Muhyo. He presents as a young, slim figure with distinctive blond spiky hair, brown-orange eyes, and a frequent necktie. Roji possesses an optimistic and deeply empathetic nature, consistently seeking the positive in others, a trait that sometimes leaves him vulnerable to manipulative spirits. His emotional sensitivity often manifests as whining or crying, contrasting sharply with Muhyo's demeanor. Despite this, Roji displays significant courage, especially when protecting Muhyo. His resilient and unwavering kindness forms a unique strength. Personal traits include a fondness for tea, sweets, and cute objects; a dislike for ghosts and frightening situations; severe motion sickness; and reliance on contact lenses for nearsightedness (with occasional glasses). He engages in creative hobbies like "super-fab-tech" (complex engineering crafts), cooking, and papier-mâché, reflecting proficiency in mathematics, physics, and handcrafting. Roji's path began in childhood when a magical law executor saved a possessed friend, inspiring his interest in supernatural law. After failing the practitioner academy entrance exam, he inadvertently attended an interview for Muhyo's assistant, drawn by signage stating "No magic law experience needed." During a subsequent grudge attack at his hotel, Roji instinctively wielded a magical staff, channeling tempering energy to injure the entity, an act that secured Muhyo's attention and their partnership. Further backstory reveals that as a child, he received "The Swallow that Defies the Wind"—a magical tool gifted by Page Klaus—to contain excessive spiritual energy attracting harmful spirits, which had previously strained his health. Roji primarily operates using a magic pen to inscribe offensive, defensive, and supportive spell seals. His signature technique, "Direct Binding," involves writing seals directly onto spirits or individuals, causing damage and immobilization. Initially lacking formal training and exhibiting fluctuating confidence, his power emerges unexpectedly in high-stakes scenarios, including once utilizing an item typically reserved for higher-ranked practitioners, indicating latent potential. His "super-fab-tech" engineering aptitude enables inventive problem-solving and gadget construction. Character development shows Roji evolving from an emotionally reactive assistant into a more self-assured practitioner. Early insecurities about Muhyo's disapproval gradually subside as he recognizes Muhyo's deliberate selection of him despite initial qualifications. His core empathetic nature drives actions that occasionally challenge rigid magical protocols. Interactions with magical law judge Reiko Imai hint at potential romantic dimensions, expanding his interpersonal dynamics. Roji's journey emphasizes growth in resilience and the strategic application of his diverse skills, reinforcing his indispensable role within the bureau.