Makoto Usui

Makoto Usui is Rikka's friend as well as a member of the school's public morals committee. After leaving Sou-kun's house, she comes back because she forgot her notebook but when back, she hears Sou-kun and Rikka in their room doing sexual related things. Afterwards she ends up in the same bookshop where Sou-kun bought the mysterious cursing book, and Zepar seels the same book to her, which will lead to her too, having her sexual urges highly increased.