Yo has shoulder-length hair that is dark with some lighter areas, likely as a fashion statement. She is most often seen with her hair half-tied. You has an almost obsessive/possessive relationship with Michiru, eavesdropping on her, showering with her, and tracking her with a GPS. She believes that Miko is a bad influence for Michiru. she even tucks Michiru into bed and does her hair for her. Yo is Michiru's older sister and manager.