Osakabe, Itoko

刑部絃子

She is a physics teacher and Harima's cousin. Itoko also serves as Harima's roommate and looks after him. Although she does not display it, she cares for him and recognizes the extent to which Tenma has altered him. The perverted boys in class 2-C admire her figure. She fears that her past will be revealed, a vulnerability that Sasakura exploits against her.
"Itoko" is homonymous with the Japanese word for "cousin," creating a pun. Because of this wordplay, when Harima says "my cousin," it can be mistaken for him saying "my Itoko."