Kiichi Ishidaira is the main protagonist of the manga series Books bought with tax. He is a high school student whose initial presentation is that of a delinquent, marked by a belligerent attitude and an intimidating appearance. This rough exterior, however, conceals a natural inquisitiveness and a deep-seated love for learning that has been dormant for many years. As a child, he was a frequent patron of his local library, but he stopped visiting for a full decade, only returning as a teenager.

His return to the library is the catalyst for the entire story. Upon visiting, he discovers that he had borrowed a book ten years prior, during his elementary school days, and had never returned it. To make amends for this forgotten transgression and to pay off the debt of the lost item, he begins working as a part-time employee at the library. Initially, he feels completely out of place in the quiet and ordered environment of the library. His decision to work there is not born from an immediate passion for the profession but rather from a practical need to resolve a past mistake. However, this job serves as the primary vehicle for his personal growth.

In the story, Ishidaira serves as the central figure, and the narrative follows his journey of discovery and change. His primary role is that of a newcomer who learns the inner workings of a public library, managing tasks such as handling book loans, reshelving volumes, and assisting patrons. Through this work, he is confronted with various problems related to damaged books and the small mysteries that surround them, which he and his colleagues work to solve. The character is guided and challenged by his senior coworkers. The most significant of these is the librarian Sayaka Hayasemaru. She is the one who sets him on the right path by prompting him to reimburse the library for the lost book, and she acts as his guide to the profession, helping him rediscover his love for reading. He also works alongside another senior coworker named Shirai.

The character’s development is the heart of the series. He undergoes a meaningful transformation from a troubled and directionless teenager into a more responsible and dedicated young adult. He begins with an impulsive personality and an attitude that seems at odds with the library’s peaceful atmosphere, but the daily contact with passionate colleagues and readers rekindles a long-buried enthusiasm for books and opens up a new perspective on himself and the world around him. What starts as a simple punishment or a way to settle a debt becomes an experience that provides him with an unexpected sense of purpose and connection. While he is driven by a natural inquisitiveness, his notable abilities are not supernatural but rather his growing dedication to his work and his willingness to confront problems directly, even if his initial approach is clumsy. As the story is still ongoing and the anime adaptation is forthcoming, his full character arc continues to be explored.