Yui Sasaki

A high school senior, Sasaki is a classmate of Nee-san. She is a member of the Broadcasting Club. She and Nee-san went to the same middle school and Sasaki hated her since then. She even abused the school's PA system just to harass her. She has a boyfriend named Yamada. He initially asked her out because of her beauty, but he quickly learned she was a total yandere. She threatens him and his family with violence whenever he tries to break up with her.