Rin is the younger of the Kagamine twins and is in Class 1-A with her older twin, Len; and fellow Host Club member, Miku Hatsune. Despite being younger than her brother, Len, she is shown to be much more mature and level-headed. Being in the same class as Miku, they serve as major rivals against Kaito for Miku's romantic attention. Len is just as playful as his elder brother, but is also a more insightful and easy-going person. She is also the first of the two to understand that their co-dependence must end, if they are to develop into separate and whole individuals. As members of the Host Club, Rin and Len are the "Little Devil" types, as they are mischievous (but not malevolent) troublemakers. They are famous for their "Forbidden Sibling Love" package, carrying out twincestuous schticks for the entertainment of their female customers. A favorite game of theirs is the "Which One Is Len? Game," in which they cover their hair with matching caps and ask people to identify Len. No one except for Miku has guessed correctly, with logical reasons for doing so.