She is Marui Bunta's younger sister, her name is Marui Bunyu.
For some reasons, I have been living in China. It wasn't until Marui Bunta was a third-year junior high school student that he returned to Japan and officially became a second-year junior high school student at Rikkai University. In the same class as Kirihara Akaya.
She doesn't have Marui Bunta's lively personality, nor does she have a face that amazes the world. I just want to live my own life normally, so I like to look for my own little happiness.