Kodaka's younger sister; she is a student in middle school, but nonetheless joins the club. She is very close to her brother, who she calls "An-Chan", and behaves in a jealous and clingy way whenever she feels that he is not giving her the attention she deserves, to the point where it is obvious that she has a brother complex. She sees Maria as a rival for Kodaka's brotherly affections and so often gets into fights with the latter. Despite being older than Maria she has smaller breasts than her, which Maria is always eager to point out.
Source from Wikipeida