Aoki "Aoki-sensei"
About
Aoki is one of the teachers in Komaki Ikeno's school.
Aoki-sensei is the person most loved and trusted by Rika Kurokawa. Rika says that his touch is the most enjoyable sensation, second only to the air she feels lying naked on the roof of the school. It's shown from the beginning that the two have a sexual relationship.
He forces Rika into being raped by many people in order to pay off debts he incurred with bad people.
He is made to disappear by Hasunuma-sensei after the horrible things he did to Rika came to light.