Osakabe Itoko is a teacher in school rumble, and she is also Harima Kenji's cousin. After Harima leaves home, she takes him in and allows him to live in her house. She often gets involved in Harima's love-life and can predict everything Harima does, to which she sets traps for him. She is often seen with Sasakura Youko. All of the perverted boys in 2-C consider her to be the hottest teacher in school.