Kyōsuke Irie is the head doctor and director of the Irie Clinic, the only medical facility in the village of Hinamizawa. He typically presents a calm, composed, and intellectual appearance, with straight brown hair parted in the front, glasses, and a wardrobe that often consists of a white coat over a black shirt, jacket, and a yellow tie. Despite his relatively young age, he is regarded as a mature and responsible figure, and he enjoys the deep trust of the villagers across all generations. In addition to his medical duties, he serves as the manager and coach of the local youth baseball team, the Hinamizawa Fighters, and takes part in various village events and organizations, including the Onigafuchi Guardians, the public relations department, and the Watanagashi festival committee.

Beneath his outwardly mild-mannered and professional demeanor, Irie harbors a strong and somewhat eccentric fascination with maid costumes, a trait that surfaces in humorous moments and occasionally leads him to behave in an undignified manner. This lighthearted side is balanced by a serious and principled core, especially when circumstances demand decisive action. His personal history is marked by a grave mistake: while working in Tokyo, he performed lobotomies without proper consent, an act that resulted in his expulsion from the medical academic society and left him seeking redemption. This past led to his recruitment by Miyo Takano to assist in researching the Hinamizawa Syndrome, a mysterious local illness. Irie dedicates himself to this research in the hope of atoning for his earlier actions, working earnestly to find a cure. He is, however, kept unaware of Takano’s true, destructive ambitions for the syndrome.

His role in the story is that of a supporting figure who provides medical expertise, performs autopsies, and conducts health checkups at the local school. He is also the attending physician for the influential Sonozaki family head, Oryo, who trusts him despite her general wariness of outsiders. Irie’s relationships with the main children are warm and informal; the young protagonists, particularly Keiichi Maeda, affectionately call him Kantoku, meaning coach. He shows genuine care for the well-being of Satoko Hojo and Rika Furude, sometimes in exaggerated or comically inappropriate ways, but his underlying concern for their health and happiness is sincere.

Over the course of the series, Irie’s character develops as his hidden past and his complicated position within Takano’s research scheme are gradually revealed. He is fundamentally a person trying to make amends for a past transgression, caught between his loyalty to his patients, his desire for personal redemption, and the manipulation of those with darker ends. His abilities lie primarily in medicine and surgery, as well as his organizational skills in managing the clinic and the baseball team. He is not a combatant, but his knowledge of the village’s medical mysteries and his access to clinical records make him a crucial source of information for unraveling the central conflicts.