Asako Shibazaki serves in the Library Defense Force, first as a Library Clerk Supervisor before her promotion to Chief Librarian. Stationed at the Kantō Library Base, she operates within military intelligence as a skilled informant, adept at gathering information. Her responsibilities also include assisting with catalog studies in the base library, where she employs a negative reinforcement training method by giving candy for incorrect answers.

Notably attractive, her appearance often draws male attention and occasional jealousy from peers. These experiences fostered a sarcastic demeanor and a habit of masking her true feelings behind a sociable exterior—a defensive strategy she adopted in high school after facing rejection for her blunt honesty. This behavior stems from a deep-seated wariness of trusting others.

Her perspective shifts through her friendship with Iku Kasahara, her roommate. Despite initial reservations, she gradually comes to trust Kasahara sincerely, viewing her as a genuine friend and marking a significant change in her approach to relationships.

In romantic matters, she is initially attracted to Atsushi Dojo because he seems unaffected by her beauty. She confesses her feelings but is rejected. Later, she enters a relationship with Hikaru Tezuka, a fellow member of the Library Task Force. Her affection for him grows over time, though she refrains from openly declaring her love.

As part of the elite Library Task Force, she plays a critical role in protecting the author Kurato Tōma from the Media Betterment Committee. She confronts Satoshi Tezuka, Hikaru’s brother, with a direct proposal: that he become an anti-censorship advocate in the National Diet. This tactical maneuver aims to neutralize his interference in the plot to abduct Tōma.