Hiyori Shiina/Relationships

Honami Ichinose
In volume 8 during the Mixed Training Camp special exam, Honami refers to Hiyori as an extremely reliable person who took the initiative and accepted the role of leader for her group.

Kakeru Ryūen
Despite Kakeru's intimidating presence, Hiyori remains calm and collected around him. Likewise Kakeru's attitude towards Hiyori is different in comparison to his attitude towards their other classmates and even those who work directly under him, as he seems to trust her.

According to Hiyori, Kakeru couldn't stand to see her always alone and quiet so he reached out and talked to her. However, since there were always a lot of people surrounding him, that made Hiyori feel very nervous so she wasn't able to stay together with him or hang out.

In Volume 6, Hiyori was willing to tolerate accompanying Kakeru during his search of Class 1-D's mastermind and encounters the members of Ayanokōji Group, who were studying together around a group table. Kakeru suspects Teruhiko Yukimura and Kiyotaka of being the one pulling strings in Class D, and asks Hiyori if she caught anything to which she denies.

Kakeru refers to Hiyori under a first name basis though the reason for that is currently unknown.

Other Classmates
Hiyori is the kind of person who loves to read books during her spare time. Thus, having no one of her classmates who are interested in such a hobby, she has nobody to talk to about it.

Kiyotaka Ayanokōji
Hiyori first met Kiyotaka after Kakeru made a contact with the members of Ayanokōji Group, who were studying together around a group table. It is possible that Hiyori noticed Kiyotaka for an indefinite span of time since she's aware of him as someone who frequently orbits Suzune.

In Volume 7, between the bookshelves under the library's section for the mystery genre, Kiyotaka meet Hiyori. While the former was thinking on borrowing another book, he observed a girl who was trying hard to reach the book titled,  by. Kiyotaka helped the girl without realizing that it was Hiyori. After he grabbed the book and gave it to her, the latter expressed her gratitude, and then afterwards, Kiyotaka spontaneously asked whether Hiyori likes Brontë's works or not. Hiyori responded by telling him that she doesn't have any special preference over the author and she just wants to put the book in the right place, in the right shelf, in the right section of the library.

After her disclosure, with an inquisitive outlook, Hiyori noticed the book titled,  by, that Kiyotaka was holding — the exact book that he succeeded from Suzune. That book, as Hiyori claimed, is a popular masterpiece that is being borrowed by a lot of sophomores, making the book's occurrence to be rare. She wanted to re-read it but didn't have the chance to find it. However, Hiyori stated that there's no problem with Kiyotaka borrowing the said book since she had a collection of interesting books in the library at her disposal. Hiyori boldly declares that she'll read each of them until she graduates.

Kiyotaka was about to leave the scene to execute the purpose he initially had in the library, but Hiyori didn't seem to be satisfied with their small talk after finding someone who seemingly has similar tastes with her when it comes to books. To continue further the conversation, Hiyori asked if Kiyotaka wants to borrow another book, to which he denied. Hiyori then immediately turned her attention to one of the shelves in the mystery section and asked if he had already read ' works. Kiyotaka claimed that he has read 's but not any of Dorothy's. Hiyori recommended the first among ' series by Dorothy — '. She affirmed that once Kiyotaka starts reading the said book, he'll be entranced to keep reading the sequel.

Hiyori noticed that it seems Kiyotaka is not particularly interested in the matter but doesn't have the heart to refuse her, so she immediately apologized afterwards for talking incessantly about books. He cleared up her uneasiness by telling her that he's just perplexed for a while but was genuinely interested in borrowing the book she recommended. Hiyori was pleased with his response, thus, inviting Kiyotaka to have lunch together. While the latter didn't expect this development — thinking that the whole thing is a fragment of Kakeru's plan — the former stated she's just a girl who doesn't have friends to talk about novels. Though classes 1-C and 1-D are currently in conflict, since she doesn't have any interest in joining in engaging either parties involved, she stated that mingling with him will not bore a problem.

After mutual consent, both of them went and a lunch break in the cafeteria. There, Hiyori had a problem in choosing a meal from the menu but in the end, she bought what Kiyotaka had chosen. Kiyotaka offered a helping hand after noticing that Hiyori was having trouble in handling her tray due to her bag. After a few dialogues, the former went to carry the latter's bag and notice that it was quite heavy — due to the fact that it was filled with mystery-related books. As they sat next to each other, Kiyotaka opened the conversation by asking her whether Hiyori usually have lunch in the cafeteria or not. Hiyori denied the question and claimed that she always buy lunch at the convenience store in the morning and eat them in the classroom, so technically, it is a rare event for her. She asked a similar query to him and said that he prefers the taste of food in the cafeteria than in a convenience store.

Meanwhile, in Kiyotaka's monologue, he noted that the way Hiyori hold the chopsticks is exceptionally charming. After that, Hiyori affirmed that the cafeteria food indeed delicious and the way Kiyotaka compared the taste of foods sold between the two sources will be kept in mind. Following the scene where they finish their meals respectively, they talk again back to book. While Hiyori was taking out the book from her bag, Kiyotaka immediately acknowledges that her choice of the book is nice. Knowing and confirming that both of them indeed like mystery, Hiyori looks elated. Kiyotaka noticed that the book she took out of her bag isn't from the library. Hiyori confirmed that it was from her personal collection of books that she always brings. The lunch break ended with Hiyori allowing Kiyotaka to take the book titled,  and his promise afterwards to return the book to her soon.

According to Mei-Yu Wang, Kiyotaka and Hiyori are able to talk naturally to one another. She regards him as her reading buddy in the library.

Hiyori starts developing feelings towards Kiyotaka as shown in her perspective while she says she wants to spend more time with him even if it's only a second longer.

Mei-Yu Wang
In volume 8 during the Mixed Training Camp, Hiyori ended up in the same group as Mei-Yu and voluntarily chose to be the one to call out to the latter when she was surrounded by unfamiliar people. Hiyori understood what Mei-Yu was feeling and kindly did her best to befriend her, comforting the latter that she and her fellow classmates were willing to become her friends. When her group was running, Mii-chan had fallen behind out of exhaustion, Hiyori seeing this from behind decides to quicken the former's pace and linked up with her. Hiyori met with Mei-Yu again at the cafe in Keyaki Mall, where the two refer to each other by their first name respectively as a sign of their growing closeness in terms of friendship.