A Grade 1 sorcerer and the homeroom teacher for the second-year students at Tokyo Jujutsu High. He is a man with a hard-boiled appearance who looks good in a coat. He lacks ambition and exudes a listless, weary atmosphere. He is currently trying to quit smoking and sucks on lollipops as a substitute, carrying a katana at his waist. Fundamentally lazy, he approaches his work with the mindset that "if I can get paid for a teaching job without risking my life, that's much easier." Despite being an elite Grade 1 sorcerer who leads the sorcery world in place of the irregular Special Grades, his true nature is timid and cowardly. While he usually acts aloof, he is reluctant to fight opponents stronger than himself because he is afraid of dying. He is in love with Guest.

While he carries a somewhat cold atmosphere, he has a strong sense of justice. Regarding the statue of Lady Justice closing her eyes for fairness, he says, "I want to be the only one to keep my eyes open," possessing a spirit that seeks to protect the weak. Furthermore, while he generally shows little facial expression, he can become quite expressive when the situation calls for it, and his face is particularly intimidating when he is enraged. There are moments where he shows a nihilistic smile while cracking jokes in front of Yuji Itadori. In his private life, he is a brilliant individual hailed as a "genius," having passed various difficult exams on his first try, including the University of Tokyo Law Faculty entrance exam and the old bar exam before the introduction of law schools. He currently belongs to the Iwate Bar Association after completing his 59th term training in Morioka. He acquired a technique that comes with a Domain by default. From that point, through just 12 days of complete self-study, he reverse-engineered everything from deciphering his technique to physical reinforcement with cursed energy. He established his combat style and attained strength equivalent to a Grade 1 sorcerer, and in less than two months, he became a genius who mastered Domain Amplification and Reverse Cursed Technique at an extremely high level.