A transfer student who aims to kill Korosensei. He is brought in along with his guardian, Shiro. Itona claims to be the younger brother of Korosensei, however, he does not appear to be related by blood. Their only similarity being that Itona can create tentacles from his hair that are much like Korosensei's. Itona is obsessed with power and aims to be much more powerful than he currently is.
It is later revealed that Itona is the son of a large cellphone company manager. He then later joins the class full-time after the students of class 3E befriend him and convince him to get his tentacles removed.