乙名 詩那

A girl that passes the image of a wild beauty that does not belong to such high-class "ojou-sama school". Is always changing boyfriends, as well as very protective of her younger twin sister. There are some rumors that she's the principal's illegitimate daughter. On the first day, when Ryou started a conversation with her to try to become friends, she answered with "Silence. Shut up. Get lost.".

She and her sister were used by Yukari to humiliate their mother by being filmed in embarrassing situations like of them peeing outside, masturbating, getting covered with semen, etc. only because Yukari was jealous of Taiga, who showed favoritism to the twins and their mother. However, on the day of the Storm, Ryou appeared and saved them when they were about to be sold as slaves. Even though Ryou lost the memories of that day, Shiina still remembers his voice, his back and the warmth of his his hug and considers him as her "Knight in Shining Armor". She's always changing boyfriends because she's looking for someone to protect her and her sister, even though said "boyfriends" just call themselves such because of her beauty and have no real or deeper relationship with her./

Future: In the prologue's future, Ryou and Mayuri remember the case where her twin classmates were kidnapped and killed. This case was so famous at the time that even Ryou, who almost never watched TV, still remembers about it.