A talented pianist who attends Yoba Academy. Her family is very wealthy, and her parents are strict, so Rei has lead a very sheltered life. She has always felt oppressed by this lifestyle, but lacked the courage to make a change. It is Rinku and the other members of Happy Around! who help her find the confidence to break out of her shell. As a part of the DJ unit Happy Around!, Rei is the keyboardist, also providing vocals and playing a part in the songwriting process.