Yui and Raku share a sibling-like relationship considering the two have been acquainted to one another since their respective childhood. This is evident as Raku affectionately addresses Yui as "Nee-chan", at least when they are alone or at home. Yui greatly treasures Raku for livening up her childhood, considering him as a part of her family and is greatly dismayed when she was separated from him. After losing both of her parents and gaining the title as head of the Char Siu, Yui greatly longed for someone she considers as part of her family and was overjoyed once she finally got the opportunity to reunite with Raku, the last person she considers her family. While it is apparent that Yui cared for Raku like a younger brother, Yui clearly states that her love for Raku extends beyond that of