Syusuke is one of the four childhood friends Sana left behind when he moved, and is still one of his new friends when he returned. He is the best friend of Sana and the only male besides Sana himself of the five friends. He is the younger twin of Syuri Wakatsuki. Yuzuki refers him as the lucky one of the Wakatsuki twins. When he and Syuri are accused of being lovers, their father decides to send Syuri to London. When Syuri says that she cannot stand to be separated from him, he decides to run away with her.