Нацусава Саку

A student at Chidori High and a close friend of Rintarou's, alongside Shouhei and Ayato.

Despite his attractive features he always appears gloomy, making him appear hard to talk to. But while he is more withdrawn than his friends he cares deeply about them and is naturally kind despite his cynical exterior. He is also incredibly intelligent, being the smartest student at Chidori High and even outdoing Kikyo's students, as noted by Subaru who begins to study with him.

Due to his standing as a genius he became isolated from his peers in middle school, resulting in his current introverted personality.