Kirin is the younger sister of Karin Kanda, and the youngest daughter of two unnamed parents. The two girls presumably grew up in Kumon-mi their whole lives. Due to being close in age, Karin and Kirin have done almost everything together, joining the same clubs, making the same group of friends and sharing the same room. Karin's natural friendliness and talent resulted in Kirin living in her sister's shadow, often being ignored by their parents and friends.
Originally, she was one of Wakana’s students, but was transferred into class C early on, probably because Wakana didn’t wanting to deal with her attitude. She initially became aware of User through Miku, who had begun talking about him constantly, a fact which surprised Kirin as Miku hadn't ever shown interest in guys before.
After spending some time with him outside of school, her interest grew and she decided to join his class. While she claims that she intentionally annoyed her teacher until they kicked her out and forced her to transfer into the only class left, I.e User’s, she let it slip that she actually asked for a transfer on the same day she told him the news near the Front Gate. She officially joined his class eventually, though her introduction was quickly surpassed by Noriko’s heart-felt reunion with User and her immediate transfer to his class.
She's part of the soccer club, along with Miku and Karin.
Being constantly compared to her older sister has left Kirin with an easily jealous and somewhat bitter personality. She easily forms and holds grudges, even for situations that were years ago. While cheery and normal on the outside, her inner self is scheming and easily bored, always trying to disrupt the status quo through unexpected words and actions. It's this cunning and seedy personality that allows her to easily get along with User while putting her at odds with the straight-laced Karin.
In addition, Kirin is extremely dishonest, both with others and herself. She'll habitually lie or, since she enjoys creating excitement, purposefully phrase sentences to push people's buttons. This often backfires on her, getting hurt when people get understandably offended or annoyed with her, firing back with passive-aggression or abrupt mood changes. Even in private, she struggles to admit her true feelings or even how hurt she is by the class' or User's sarcastic comments.
While she usually doesn’t care about other people and how they feel, she still shows some empathy and understanding to those she deems worthy of it. She’s shown to care deeply about Miku's well-being and is especially sensitive about her family situation. She displays a similar level of care towards Noriko during her emotional outburst on Halloween and after User bails on their beach date and continues to support her, even through her many complaints. She was also the only one who helped User when he was feeling down after what happened with Molly, even acknowledging that her behavior from before went too far.
Despite the ongoing space war, Kirin's father seems to still be around, suggesting he is exempt from serving for one reason or another.