Ryusei Koki is a canon character who attends Akademi High School.
Ryusei has cobalt blue hair that has been swept back to the right. He has two strands of hair hanging over his forehead. His eyes are cobalt blue as well. His uniform is dependent on the player's choice. He wears blue glasses.
Ryusei has the Teacher's Pet persona. If Ayano tries to take a picture of him without being in the Photography Club, he will cross his arms before giving her a suspicious look. If he witnesses murder, he will report it to his teacher if another Teacher's Pet hasn't already.
- His current name is a reference to the most popular male Japanese names in 2012, the seventh being Ryusei and the eighth being Koki.
- His female counterpart is Mei Mio.
- He was originally in the Gardening. After that, he was in the Light Music Club, then the Art Club. He is currently not in any club.
- He used to arrive eleventh to school, sixth in line on the left side at 7:05 AM.
- His hair was inspired by Lloyd Irving from Tales of Symphonia.