RelationshipsRumi's peers include Yokko (Voiced by : Megu Sakuragawa), Mori (Voiced by :Haruka Shiraishi), Hitomi (Voiced by :Erii Yamazaki), and Yuka (Voiced by : Ibuki Kido). These four girls were part of Rumi's group during the Chiba Village Summer Camp.
Rumi herself mentioned she would bully other girls with her classmates, but only because everyone else did it. They would get bored after a while and pick a new girl to bully. However at some point they started picking on Rumi and haven't moved on.
They don't consider Rumi to be socially equal to them, as they talk behind her back and gossip about her. They are Rumi's bullies. Rumi is not mean back, she is actually very kind to them and only wants to fit in. She even "saves" them during the summer camp arc. Although their relationship after the camp is still questionable, Hachiman notes at least the bullying had stopped.
RepresentativesRumi has a formal relation with the seven other representatives for the Christmas Collaboration Event. Rumi is still seen as a loner always sitting off to the side or working on her own. Rumi is shown to at least work cooperatively with the other representatives, she even takes charge when they don't know what to do.
During the Christmas collaboration event between Sobu High and Kaihin Sogu High, Rumi recognizes Hachiman right away. She even asks him what her group should be doing when they are ignored by Tamanawa.
Rumi was very happy when Hachiman helped her make Christmas decorations. Although she doesn't like the nickname he uses, RumiRumi.
Hachiman sees that his method did save her from bullying, but he feels that it might’ve not been enough as she is still alone and seems lonely.
Rumi is one of the few to call Hachiman by his first name and demanded him to call her by her first name as well (Episode 10,Volume 9). Rumi was shown to be happy when Hachiman called her by her first name.
In light novel, after making Rumi the star of the Christmas play, Hachiman watches Rumi receiving well-deserved praise. Hachiman also praised Rumi's "celebrity quality" in his own mind but left the area without seeing or saying anything to her again. Thus Hachiman succeeded in finishing what he felt was left incomplete. Hachiman feels that Rumi is genuine, for she lent a hand to her peers even though she knew them to be fake, poor friends.
Saika, Komachi, Yumiko, Hina, Tobe and Yui are sympathetic towards Rumi, and tried to help her socialize. It is possible that she was aware of the reason behind Hayato, Yumiko and Tobe's delinquent act at Chiba village summer camp. Yumiko feels that Rumi has the same attitude as Yukino.
Rumi identifies Yukino as someone like her and Hachiman when they first meet. However she is less open with her feelings to Yukino that she is to Hachiman.
Most characters seem to think Rumi could be similar to Yukino's past version. Yukino was able predict Rumi's future social condition and there are hint's of Yukino having a similar bullied and excluded experience. Yukino also mentions to Hachiman, her desire to improve Rumi's situation
Hayato wishes to make difference in Rumi's social life however he can. It is possible that Rumi's situation reminds Hayato of a trauma or something close to his past. Yukino even pointed out that Hayato can't get this matter out of his mind. Hayato also tried resolving Rumi's situation, but failed.
After failing with his methods, he goes against his instincts and accepts Hachiman's plan to scare Rumi's group. In Volume 9 it was mentioned that Hayato, along with his clique praised Rumi for her performance in the Christmas play.
Rumi didn't accept Yui as one of them (Loners: Hachiman, Yukino, Rumi) and states that she belonged to Hayato's group. After seeing Hachiman and Yukino include Yui in their group, she starts to talk with her more openly.