Hitomi Kashiwa

Hitomi Kashiwa was Tatsuhiro Satou's Senpai during their high school years, and is currently the fiance of Akira Jougasaki.

After asking Satou to join the literature club, Satou did so. However, since they were both shy, they were only seen debating conspiracies and played cards. In the manga and Light Novel, it is made blatantly obvious that she and Satou had sexual relations, but all that terminated as high school was coming to an end. However, in the anime, it is a relatively debated subject as to whether she had sexual relations with him, as they had only hinted at the fact that they might have during flashback scenes.

As hinted in an early flashback, she had suicidal tendencies even back in high school, implied by the sentence "Would you be sad if I died?". The general scene also implies Hitomi's willingness to continue their relationship after high school, however, Satou is seen filled with regret in all forms of media for not having continued the relationship.

She is attributed with filling Tatsuhiro with negative thoughts, as she litters his mind with ideas of conspiracy, indirectly encouraged his drug usage, and even almost committed group-suicide with him involved. As Satou did not have many other relationships in his high school years, he was manipulated into her frame of mind. She gives him false hopes for a relationship, but often cannot help branching her intimacy.

However, aside from Satou's mother, she has known about the inner workings of Satou for the longest out of anyone. Once rejoicing, she repsonds all but surprised as Satou confidently shouts that he is a hikikomori. She was often seen in flashbacks anticipating his next moves, and shows extreme tolerance to is behavior.

In the manga, Hitomi has a much closer relationship with Misaki Nakahara, but not on the best of terms. Satou tends to be drawn to the magnet pulling the hardest at any given moment, and since Hitomi had suggested the idea of an affair with him, it is reasonable to believe that she had not detracted so much from him after high school, as well. Misaki is well aware of her influence of conspiracies and drug usage to Tatsuhiro, and punishes him after repeated encounters with Hitomi.