|Birthday||January 15 (Capricorn)|
|Role||Tenor Saxophone player|
|School||Kitauji High School|
|Occupation||Student (third year)|
Aoi is a young girl of below average height and build, who wears the standard Kitauji High School uniform for third year students. Her dark brownish green hair is braided, her bangs are clipped back by two light blue barrettes, and she has light green eyes.
Aoi is a very friendly young girl, who is rarely seen being mad or upset. She is calm and takes everything nicely. But she is also mature and understanding, giving Kumiko advice, and she also knows how to take responsibility.
Aoi was first introduced in Nice to Meet You, Euphonium, where she appears when Kumiko and Shuuichi were talking, and thus meeting them after a long time.
Later, in Crybaby Saxophone, she announces that she will be quitting the band, since she is currently struggling with balancing academics and participation in the concert band, in order to focus her attention on her academics. She was also partially motivated to quit because of her disappointment in her inability to prevent the schism of the previous year from transpiring.
Kumiko and Aoi are childhood friends that lost contact but are later reunited when Kumiko joined the concert band in Kitauji High. They are on good terms, often chatting and hanging out after school despite Aoi being two years older than her. Kumiko can openly talk to Aoi when she needs help, since she knows Aoi is a very kind person and will listen. After Aoi quit the band, they, once again, lost their contact; since the two are rarely seen to interact anymore and Kumiko was sad to find out that Aoi never really regretted leaving the band.
Shuuichi is also Aoi's childhood friend. They haven't interacted much, but they seemed to have a close relationship is the past, and they later developed a quite friendly relationship after reuniting in high school
- Aoi resembles Youko Sasaki, a side character from K-ON!, which is also animated by Kyoto Animation.
|Characters of "Hibike! Euphonium" Universe|
|Kitauji High School||First Year Students||Kumiko Oumae • Reina Kousaka • Hazuki Katou • Sapphire Kawashima • Shuuichi Tsukamoto • Chikao Takigawa • Chieri Takashita • Tsubame Kamaya • Akiko Yoshizawa|
|Second Year Students||Takuya Gotou • Natsuki Nakagawa • Riko Nagase • Yuuko Yoshikawa • Nozomi Kasaki • Mizore Yoroizuka • Tomoe Kabe|
|Third Year Students||Asuka Tanaka • Haruka Ogasawara • Kaori Nakaseko • Aoi Saitou • Hirone Torizuka • Kotoko Himegami • Juri Sawada • Shouko Hagiwara • Yoriko Souga • Tsune Watabe • Raina Kitamura • Oka Mikino • Sana Kasano • Hideri Noguchi • Narai Tanabe|
|Others||Noboru Taki • Michie Matsumoto • Mamiko Oumae • Akiko Oumae • Kohaku Kawashima • Azusa Sasaki • Masahiro Hashimoto • Satomi Niiyama • Saki Kayama • Junichi Takino • Noboru Taki's wife|