In part 1, Sayu disliked him at first. She didn't like the fact he was friends with Hikari, the boy she believed was the course of upsetting her friend, Miuna. Kaname finds Hikari picking on her, and asks her if she is ok, as he pats her head to comfort her. She appears flustered, but yells at him, telling him not to touch her with his "fishy smelly hands". After Kaname confronts her for ruining the Wooden Maiden, she begins to cry, because she knows what she did was wrong, leading her to admit she was only acting horrible because Hikari was the reason that Miuna was upset. Kaname, seeing her soft side, pats her on the head and tells her that she is a good girl. Because of this, she starts to have a crush on him.
In part 2, it is shown she had grown in love with him and is upset because Miuna is booting about Hikari coming back. She wishes Kaname would wake up, but when he does, she wishes that it never happened, because she wanted to be an independent woman and not rely on a man. Sayu is hurt when she sees Kaname again, realizing he doesn't remember her. She started to cry, and in fear that he would notice, she ran away, as he to finally figured out who she was. Later one, Kaname waits for her in the same spot and when she comes by, he walks towards her to see her. He smiles at her and is glad to see her all grown up, he comments on how they're the same age when he goes to pet her again but stops. Sayu blushes bright red and shyly looks away as the two talk more. Kaname talks about Sayu with Hikari, about how she has changed and that he may like it.
Later on, the two grow closer. When Hikari and Miuna are out sick, he questions why Sayu is taking three sets of notes and is pleasantly surprised to find that she is taking notes for Miuna, Hikari and Mananka to which he gladly offers to help her with. Also, he is happy to know that she cares for him when she asks if he feels alright since he had also been going into the sea with Hikari, which she believes might lead him to getting sick. He tells her that he feels fine. Later, the two take the notes to Hikari together. It is unclear if they spend the rest of the day together or not.
Soon after, Sayu decides to confess to Kaname after he overhears Chisaki and Tsumugu's conversation. She goes after him and calls him out on not being more up front when he "asks out" Chisaki. He repeatedly mentions that he was never noticed or loved by Chisaki, and she tells him that he was in her heart the entire time. He then confesses that he believed no one was waiting for him to wake up. After he realizes her feelings, they are accepted. At the end of the last episode, Kaname asks Hikari if he and Manaka have made progress, and suggests that they go on a date, implying that Kaname and Sayu may be going out.
In part 1, it is shown that Sayu and Miuna are close friends. Later, Sayu admits Miuna is her best friend and before they became friends, she was picked on and when the bullies changed their target to Miuna she was relieved. She didn't understand why Miuna didn't care about being teased, so Sayu confronted Miuna about it. Miuna simply stated that she doesn't care about what anybody thinks. After that, Sayu decided she wouldn't care either and started a friendship with Miuna. Sayu tries her best for Miuna, does everything for Miuna. Sayu finds Miuna a little selfish but doesn't care for it. She disagrees with a lot of things Miuna does as she admits to Kanamae after he confronts her.
In part 2, it is revealed that Sayu isn't very close with Miuna anymore. Sayu admits that she doesn't like how Miuna acts, despite this she still considers Miuna as her closest friend. She gets upset at Miuna for many things, such as how selfish she is and how Miuna speak to her about Sayu's own feelings. Miuna acts like a bad friend in one episode, to which Sayu forgives. Sayu is excited when Miuna invites her along with herself and Hikari but is hurt when Miuna simply wanted her around so not to scare Hikari. Sayu doesn't like the fact Miuna likes Hikari, she disagrees with it for many reasons, one of which him being her uncle and stating to Miuna , hoping to clear her head that uncles and nieces aren't allowed to get married, to which Miuna throws back in her face angrily. Later, Sayu forgives Miuna as she fears Miuna had hurt herself when she finds Miuna's boot. Despite Miuna still doesn't understand, Sayu brushes it off hoping they could stay close friends. Later, Sayu notices Miuna being selfish once again and confronts it. When the two are looking for anything to help Manaka, she notices Miuna withdrawing from every idea which makes her angry when she realizes Miuna doesn't want Manaka to wake up. She says this angrily before leaving Miuna to her thoughts. Still upset with Miuna, she brushes off her own feelings when she finds Miuna pretending to be sick to at lest make her some notes.
In part 1, Sayu used to spy on Manaka and her friends. She is grateful for the fact Manaka treated her like a normal person and not an annoying little girl. Still so in part 2, Sayu looks up to and respects Manaka for everything, especially for saving them.
In part 1, because Miuna was upset at him, Sayu tried to cheer her up by acting hostel against Hikari. She thought Hikari was Akari's boyfriend by apologized later, when she found out he wasn't. Once she had changed her view, she began to respect and look up to him as he treated her like a young sister. Sayu likes to tease Hikari, just as he teases her.
Chisaki is another person Sayu respects and looks up to. Despite she thinks Kaname may still love her, Sayu doesn't hold it against her and hopes that one day Kaname may look at her that way.