Ayumi Azuchi teaches at Graviton High School, responsible for the class including A-ko, B-ko, and C-ko. Her duties involve managing classroom dynamics, specifically preventing conflicts between A-ko and B-ko and attempting to educate the easily distracted C-ko. Haunted by the death of her parents, she fears she will never experience romantic love or marriage; this underlying loneliness propels her decisions. She is also an active member of the Volunteer Defense Force, mobilizing to protect Graviton City during emergencies. For these missions, she adopts a distinctive, skimpy superhero costume—a remnant from the franchise's initial adult-oriented development—and utilizes a gravity-defying cycle for transportation. Her interests include literature, fireworks displays, and swimming.

In "Project A-ko 4: Final", facing ongoing romantic disappointment, she enters an arranged marriage with Kei, orchestrated by Hikaru Daitokuji. This engagement becomes a central plot point, provoking intense reactions from A-ko and B-ko, who are both infatuated with Kei. Concurrently, she exhibits mysterious behavior, wearing a heart-shaped crystal pendant marked with a hexagram and chanting private prayers. This pendant is later revealed identical to an artifact discovered in ancient Babylonian ruins, linked to apocalyptic prophecies concerning an alien princess.

The wedding ceremony in the high school gymnasium descends into chaos, simultaneously disrupted by A-ko and B-ko's violent interference, the arrival of the Alpha Cygnan alien fleet intent on retrieving their princess, and the intervention of the Earth Defense Force. Ayumi, Kei, and C-ko are caught in this large-scale conflict. Her storyline culminates in profound frustration when she smashes her pendant, disillusioned by its failure to grant her the extraordinary life or significance she anticipated.