Yomikawa Aiho is teacher at Touma's school and a friend of Komoe. She is beautiful, has glamorous proportions, and is always seen with a green jersey and often ends her sentences with "-jan". Despite having a glamorous figure, she acts in a tomboyish matter and regularly joins colleague Tsukuyomi Komoe in drinking sessions after their work. She also always tease Komoe, her senior & friend.
She is a member of Anti-Skill and cares deeply for her students (in spite of having a "spartan" approach in teaching according to Komoe), and is an active peacekeeper within Academy City. Due to her habit of ramming delinquents with protective items like shield or helmets to resolve incidents, saying it's alright to do so since those are protective items, she's known as 'the woman who uses comedy-like methods to solve problems that could end up as a tragedy'.
As a favor to her old friend, Yomikawa is asked by Yoshikawa Kikyou to take care of Accelerator and Last Order after they are released from the hospital.