He is a government worker associated with the Ministry of Defense. He first appeared announcing Korosensei's deal with the government and their mission to assassinate him before the end of the year. He later became the assistant teacher and P.E. instructor of class 3-E, using his lessons to train the students in assassination techniques. He is well known among militaries for his outstanding reputation and is a powerful individual, which he has proven when he easily overpowered Irina's master, who is a retired professional hitman, and even Korosensei himself is afraid upon seeing his capability for the first time. He is strict, but kind man, though he keeps a distance between himself and the students due to his status as an agent and his own professionalism. He is one of a few who is very perceptive enough to see Nagisa's talent as an assassin. He seems to know Korosensei's past, though he has no intention to indulge into it further.