Shirou Mochitsuki
He is Madoka's classmate in Graphic Design and friend. He is also Rie's sex partner and revealed that they were high school friends. Because of his wealth, he doesn't have any friends during his high school days. He also claimed that he likes Emiru and wants to have sex with her. After he found out the peep hole, he blackmailed Tatsuhiko and Emiru. He also attempted to have sex with Emiru during his stay over but it turned out to be unsuccessful because of Tatsuhiko's idea. In the end, he kept about the secret and asks to aid Rie over her jealousy in others' happiness.