|Class and Year||2-F|
|Physical and Vital Statistics|
|Manga||Volume 2 Chapter 8|
Rin Eiyuuzaki is introduced as a girl to help Souta in the athletic festival.
She has a responsible, strict and strong-minded personality. When she meets everyone from the dorm she introduced herself properly while yelling. She said she wouldn't forgive Souta if they didn't win the sports festival and after Souta said that they needed to win, she got embarrassed.
She is friends with Kikuno and reveals that she has a boy childhood friend nicknamed Souda who moved but she keeps in contact with him by email. However, when she discovers Souta is that person, she retreats in embarrassment by apologizing for her treatment towards him and occasionally revealing a yandere flag. However, once Souta assured her that their friendship won't be tarnished by such a fact she showed a more girly nature that caused Souta to question if she was really the same Rin he knew as she is now.
Her interactions with Souta change, as she now gets flustered and blushes around him especially after recalling when they were little they did everything together.
She got along well with Okiku and was even in the same class, but after she went abroad to study Rin hardly got time to see her. She only joined the dorm because Mimori said she should join, so the dorm could win the sport festival.
Although she didn't wanted to join she forced herself, because she owed the president. She made a plan that the sixth day would be the day that decides it all and the other days she would train everyone, so they could win the sport festival.
Later on, she told Souta that when she was younger she was also a strong minded person, but she had a friend who treated her equally and she said he was a really good person. She regarded him as her best friend though she hasn't seen him for a while they are still exchanging mails. Souta said that he also knew a person named Rin, but the Rin he knew was a boy and he also called him Souda. After that Rin said that she would send a mail to Souda and when she sent the mail, Souta's cellphone rang and the message she sent was on his phone, making it clear to them that the friend she was talking about was Souta from the start and the boy Rin that Souta was talking about was actually Rin who wore a hat over her long hair as a child.
When the two realized the other's identity, they freaked out with both questioning the supposed change in the other's attitude and appearance until Rin nearly fell and Souta quickly saved her. After seeing he was still the Souta she knew, Rin broke down and repeatedly apologized to him for her behavior towards him, as this happens Souta spot a yandere flag on her head. Not knowing any other way, he tells her that their friendship won't be tarnished because of such a thing when she asks if that's true he affirms that it won't. Rin's flag breaks as she realizes he is right and Souta is confused by her girly nature compared to when they were children.
Rin tells the others and they are surprised by her and Souta's connection (Nanami questioning how they didn't notice) and she states she will call him by his name as he is embarrassed being called Souda.