Tanaka, Yoshitake's older sister, is a third-year student at Sanada Central High School. She presents as slim and of average height, with short brown hair secured by a yellow hair clip, typically wearing her school uniform; her eyes are never visually depicted. She remains primarily known by her surname. Her personality exhibits a stark public-private contrast. Around her brother Yoshitake Tanaka (a North High student) and his friends, she displays strength, a quick temper, and violent tendencies, openly picking on them for amusement while hypocritically criticizing their behavior. Yoshitake describes her as "crazier than himself" and notes her compulsive lying. Specific topics, like her inability to get a boyfriend, provoke intense reactions; this romantic desperation leads her to engage in relationships she claims to find undesirable, such as pretending to date Yuusuke. However, a markedly different, well-mannered side emerges when she is almost completely alone, a trait Yoshitake finds annoying. Her notable physical strength intimidates the main trio of boys. When enraged, she effortlessly threw a concrete block several meters and physically overpowered and threw Tadakuni "like a ragdoll". She acts as the ringleader within her social circle, which includes Motoharu's older sister and Tadakuni's younger sister. In one incident, she led a group trapping Motoharu near the station. They surrounded him, mocked his appearance, suggested alterations, restrained him despite his struggles, and forcibly shaved his beard. Among the three prominent "eye-less sisters" in the series (alongside Motoharu's older sister and Tadakuni's younger sister), she is distinguished as the only one whose last name (Tanaka) is known, while her first name remains unrevealed. She ranked 35th in the series' character popularity poll.