Miyuki Kujou

During volumes 5 and 6 it’s revealed that Kimito and Miyuki were childhood friends with a relationship similar to brother and sister, when young she was used to calling him “onii-chan”. As a child she was never really close to her real older brother and was always feeling lonely since her status of “Oujou-sama” left her alienated and timid. When Kimito was found to look exactly like Miyuki’s older brother they switched places easily, while switched Miyuki found out that he was not her real older brother, the both spent a lot of time together living as a family and Miyuki finally had someone to trust and lean on.