Rika has heart condition called hypoplastic left heart syndrome. The condition is fatal if untreated, but Rika has gone through a reconstructive heart surgery as a toddler. Even so, she still left physically weak and at a constant danger of complications. A string of hospitalizations has made Rika a loner, but not a lonely person. She is sometimes hard to get through to, and tends to get lost in thought even in crowds. People think she is shy but she can get along with most people. She is aloof.