They don't have an official setting.Those of Ты who are convinced that Rin and Len are either twins, или only mirror images, Ты are BOTH wrong. EVERY SINGLE VOCALOID plays a different role in each song. In some songs Miku & Kaito are dating, in others they are not; SO ARE THE KAGAMINES RELATED IN SOME VIDEOS. Obviously, in this video, the role they are playing IS twins. Now, if Ты watch Kokoro, или Paper Plane, they are NOT. Again, in Daughter/Servant of Evil, they are.