Rui is a talented violinist who has played the violin ever since she was young. However, at some point in her life, she lost in a competition against Rinko Shirokane, came to the conclusion that she has no true talent and as a result, quit playing the violin. Rui is also a member of Tsukinomori Girls' Academy's student council. She initially tagged to Morfonica's band practices only because they needed someone from the student council to monitor their activities.