Basara Toujou: In the beginning, she treated Basara like the older brother she never had. Five years later, she showed nothing but hatred towards him after the incident. She even deemed him a traitor when she found out that he was not only living with Mio but also protecting her as well. After her battle with Basara, she reverted back to her old self calling him her big brother like she used to but also at the same time began to develop romantic feelings for him.
Yuki Nonaka: They are sisters and she's very protective of her.
Maria Naruse: They cohabiting with Basara and others.
Celis Reinhartd: As a child, Kurumi idolized Celis and admired her great strength.
Mio Naruse :After moving into the Toujou household, Kurumi and Mio quickly become friends thanks to sharing a bath together. The two girls often have similar reactions to various events in the series.
