Yuu is Seiko's little brother and the eldest son of the Shinohara family. He holds complex feelings for his missing mother, and in truth he still wants to be spoiled like a child. As the eldest son, he has to behave courageously and determinedly; he is always willing to take care of household chores and watch after his younger siblings. Since he is dependable and kind to girls, he is very popular among the girls in his class. He's unaware of that however, and believes that this is the natural way one should act. Since he can be relied on in a pinch, he also has many friends.