Yumi Omura is a 17-year-old girl who works at the Japanese pub, My Pleasure, alongside Hideki. She is the daughter of the club's owner. It is initially implied that Yumi was interested in a relationship with Hideki, but as the series progresses it is revealed that she initially approached him because he also worked at Club Pleasure, and that she thinks of him as a big brother. Throughout most of the series Yumi has an inferiority complex toward persocoms, and becomes upset at any mention of a human-sized persocom.
The reason for this is that while Yumi was working at Chiroru she fell in love with the manager, Hiroyasu Ueda. She gathered the courage to tell him, and found out that he reciprocated her feelings. All would have been well, except that Yumi discovered that Ueda had previously been married to a persocom that he had named Yumi, and she thought that he would compare the human Yumi to the persocom Yumi and find the human Yumi inferior.
However, Hideki eventually manages to persuade Yumi that Hiroyasu wouldn't have started anything if he didn't love Yumi for who she was, and he and Yumi start going out again.