Izumi Aomi, a student at Miyasaka High, starts as a delinquent known for skipping class and secretly smoking. She has shoulder-length golden hair with bangs on the left side, violet eyes, and a tanned complexion. After joining the student council, she replaces smoking with constantly having a lollipop in her mouth.

A growing brain tumor limits her lifespan; doctors predict she won't live past 18. This diagnosis propels her thrill-seeking nature, making her embrace supernatural events at school as exhilarating opportunities rather than threats. She treats conflicts involving vampires, demons, and magic like an engaging game, often providing comic relief during tense moments.

Intrigued by the student council's connection to unusual events, she snoops around and gets caught by Cross Philier Yuuchi. He appoints her secretary on the condition she quits smoking. Her unexpected organizational skills and academic prowess—notably outscoring president Gekkou Kurenai in home economics—gradually earn Yuuchi's recognition. Initially lacking magical abilities, she receives basic magic training under the << Military >>. Later, she asks Saitohimea to adjust her brain for better magic attunement; this process accidentally exposes her tumor, though she insists Saitohimea keep it secret from the council.

Her cheerful and direct personality fosters close friendships, particularly with Saitohimea and Mirai Andou. She openly roots for their romantic pursuits, playfully acting as a self-appointed "love messenger." Resourceful in a pinch, she once lured an attacker into lowering their guard during a fight with Temperon Crowley’s allies, enabling Saitohimea to strike. In the kitchen, she excels only at cooking curry. During the council’s training sessions, she frequently cheers from the sidelines, maintaining her role as an enthusiastic observer despite her non-combatant status.