Ayaka Yukihiro, serving as class president of Mahora Academy's Class 3-A, is also known as Iinchou and Biblio Red Rose. She occupies seat number 29 in Japanese alphabetical order and consistently ranks among the top academic performers in her grade, achieving fourth place in recent examinations. Coming from a wealthy background, Ayaka possesses strong knowledge of both Japanese and European social etiquette.

Upon the arrival of the young teacher Negi Springfield, Ayaka forms an immediate and overt infatuation with him. She justifies this interest by claiming he requires a mother figure, though her classmates frequently misinterpret her behavior as an attraction to younger boys stemming from a tragic past event. This misunderstanding leads some classmates to view her as clueless despite her intelligence. Ayaka often acts as a stabilizing influence within the classroom, compensating for Negi's inexperience in managing large groups.

Ayaka shares a complex relationship with Asuna Kagurazaka, characterized by frequent disputes and a love/hate dynamic. Despite outward animosity, they maintain a deep, unacknowledged friendship that culminates only near the series' conclusion in an emotional mutual confession of care. Ayaka serves as Asuna's closest confidante. Her participation in the Miss Mahora competition, initially declined due to academic priorities, is secured upon learning Negi is the prize.

During class activities like the Kyoto field trip, Ayaka interacts with classmates including Kazumi Asakura, Chizuru Naba, Natsumi Murakami, and Chisame Hasegawa in group settings such as hot springs. In the formation of the combat team Ala Alba (White Wing), established to search for Negi's father in the Magic World under the guise of a school club, Ayaka is among the classmates who accompany Negi on this expedition. The team faces challenges including ambushes that scatter members across the Magic World.