Shizu Shidou  

, 祇堂静珠

Shizu is the twin sister of Mariyas. She attends an all-boys school that was previously run by the ex-chairman. Like Mariya, she has a similar fear/hatred of males and had experiences comparable to Kanako, whom she affectionately calls Kana-chan. Unlike Mariya, Shizu seems to be the kind and innocent girl that Mariya tries to portray. She is also quick to get her feelings hurt. The agreement for the competition was that the loser would be chosen if someone from either school discovered their gender. Kanako, assuming Shizu was Mariya, mentioned Mariyas touching her, which revealed to Shizu that Kanako knew Mariyas gender, thus defining Mariya as the loser. Although Shizu had only gone into the school to switch places with Mariya for their schools physical examinations, because Kanako found out Mariyas secret before she started attending the school, it was null. Because Kanako knew Shizus true gender, ordinarily, Mariya would have been declared the winner. However, out of generosity, Mariya chose to overlook it in favor of his twin sister. The only way to differentiate between Shizu and Mariya is by the mole under their eyes; Mariyas is on his left side, while Shizus is on her right side. She stands at 160.6 cm tall, which makes her slightly taller than Mariya, a point that seems to be a source of contention for him. The two siblings frequently compete with each other in various aspects, including height, weight, and studies.