Mei Mio is a canon character who attends Akademi High School.
Mei has cobalt blue hair that is styled in a bun. Her bangs are longer on the right side and she has an ahoge on the top. Her eyes are also cobalt blue. Her uniform is dependent on the player's choice. She wears a blue friendship bracelet on her right wrist, along with blue stockings, panties, and glasses. Her bust size is 1.4.
Mei has the Teacher's Pet persona. If Ayano tries to take a picture of her without being in the Photography Club, she will give her a suspicious look. If she witnesses murder, she will report it to her teacher if another Teacher's Pet hasn't already.
- Mei's name was at one point Tsumugi Kotobuki, and then later on Tsumu Kotobu. These names were inspired by K-ON.
- Mei's original hairstyle was replaced in the February 8th, 2016 Build because YandereDev thought that it was "low budget" and "amateur-ish". He has also stated that he never liked her iconic tri-tail look, as he thought it was "ridiculous".
- Mei was originally in the Gardening Club. After that, she was in the Art Club. She is currently in the Cooking Club.
- Mei's male counterpart is Ryusei Koki.
- Her current name is a reference to the most popular female Japanese names in 2012, the seventh being Mei and the eighth being Mio.
- She used to arrive fifth to school, third in line on the left side at 7:05 AM.