Tanaka's little sister. She is a middle school student who is the manager of the Volleyball Club of her school. Rino is often told that she is similar to Tanaka as they both have a listless look in them. Unlike her brother, Rino is more consistent and is normally the one doing the shopping, cooking, cleaning etc. She has grown the habit of cleaning leather shoes as shown when Oota paid a visit to Tanaka's apartment. It is also shown that Rino has Brother-Complex, or "brocon" as she purposely gave Oota dark chocolate knowing that he loves sweet things and gave Tanaka hand-made sweets. She expresses a dislike towards Oota, brought about by Oota and Tanaka's close relationship and sometimes gets jealous. She is friends with Oota's younger sister Saya