Mio Yamagishi is a member of the Prince Yuki Fan Club and adores Yuki Sohma. She is the First-Year representative for the club, hoping that by the time that she reaches third-year, she will become the president of the club.
She is a bit of an airhead, but she's more self-absorbed than the others. It can be assumed that she's not very smart or greatly lacks foresight as she hopes to become president of the Fan Club, but is ignorant of the fact that Yuki will be long gone.
She has short red hair with bangs overhanging her forehead, and blue eyes.
Role in the Story
Before Summer Vacation
Mio accompanies Motoko Minagawa and Minami Kinoshita to Saki Hanajima's home, pretending to be doing research on her powers to learn Saki's weakness so she can defeat her and Tohru Honda to protect Yuki Sohma. She fantasizes that Saki's house is in a graveyard, with ivy growing all over an ancient chapel; instead, it turns out to be an ordinary house.
When they go inside, Saki warns them not to speak their real names in the house, but didn't tell why. When Saki leaves to make tea, they dive into her room, looking for everything personal they can find (it is noted that they seem rather used to doing so). When Motoko Minagawa (the President of the Prince Yuki Fan Club) opens a sliding door, she saw Megumi Hanajima instead, and screams as Saki returns with the tea. Saki then invites Megumi to join them, who asks if Mio, Motoko, and Minami are Saki's new friends. Saki's reply causes the three to think, "Is she being sarcastic?!"
While drinking tea, Motoko asks Megumi if he can emit waves like Saki. Although initially relived to hear him say no, they quickly discover that he can curse people through their names (which is why Saki spoke of not saying their real names). When he asks for their names, Motoko and Minami try and leave, but not before Mio asks Saki directly if she has a weakness. When Saki confirms this, they all listen intently, but Saki redirects the conversation, revealing that she was aware of their plot.
With their secret out, Motoko reveals their intentions. However, Megumi tells them that they themselves are disrespecting Yuki by acting the way they do. He then reveals that he indeed knew their names (as they spoke their names when Saki was out making tea, and his room is past the sliding doors that Motoko opened), and they run away.
After Summer Vacation
She has various other minor roles in the series; however, most notable is when she and several other fanclub girls are seen bullying Machi Kuragi, the treasurer of the student council during Yuki Sohma's term as president because Machi sees that Yuki is lonely despite being surrounded by people, and does not think he's like a prince. Kakeru then announces that Yuki will be doing a photo shoot in front of the school, and the girls run over, not realizing it was a fake announcement (however, the student council winds up having a photo shoot for the crowds of girls that had come anyways).
- Minami once states that once Motoko graduates, she (Minami), will be the Yuki Fan Club's president, and Mio would be next. However, Takaya (the author) states in a side-note that she did not realize Yuki would have graduated by the time Mio was president.