Youhei is Tomoya's friend and also a delinquent. He entered the school on an athletic recommendation in football (soccer), but was kicked out of the soccer club after being involved in a fight. After this incident, he became lazy, becoming the only student with a higher absence rate than Tomoya. He and Tomoya are known as the "Dirty Pair" in school.
Youhei plays a major role in some character paths. Youhei plays the most role in Sunohara siblings' arc, which centers around his relationship with his sister Mei, who tries to bring back her brother's former self.