Jirō Tomitake is a recurring character who first appears as a freelance photographer visiting the village of Hinamizawa several times each year, primarily to photograph local birds and the annual Watanagashi Festival. He is a tall, muscular man in his late thirties with short brown hair and brown eyes, always seen wearing glasses. His typical attire consists of a dark green baseball cap, a black sleeveless shirt, green military trousers tucked into black boots, a dark brown belt with attached pouches, and a dog tag necklace. His build and posture suggest military training, and his polite, unassuming manner makes him easily accepted by the villagers.

Tomitake's public persona is that of a cheerful, easygoing, and somewhat carefree outsider. He is warm and sociable, quickly befriending the local children and earning playful acceptance from Mion, who makes him an honorary member of the club. He laughs readily, often to deflect awkward questions or uncomfortable predictions. Beneath this genial exterior, however, he is a deeply serious and capable man. He works as a lieutenant and auditor for a shadowy government organization known as Tokyo, where he oversees budget allocation and serves as a liaison between the capital and the Irie Clinic's research on Hinamizawa syndrome. His name is an alias; his true identity remains undisclosed. Tomitake was formerly a sniping instructor in the Japan Self-Defense Forces before an eye injury ended that career, and he retains exceptional marksmanship, as demonstrated in Matsuribayashi-hen when he accurately fires from a speeding vehicle. He also possesses lockpicking skills, having opened the sacred storehouse's padlock with simple tools.

His motivations center on duty and personal affection. He carries out his liaison work diligently, but his loyalty is complicated by his romantic feelings for Miyo Takano. The two maintain a close, ambiguous relationship—he pursues her persistently, and she plays along, using his attachment to further her own agenda. He genuinely wishes to help her uncover the truth behind Oyashiro-sama's curse, even as he becomes an unwitting pawn in her larger schemes. In most story fragments, Tomitake is injected with the drug H-173 by Takano's agents on the night of the festival, triggering a violent psychotic episode that causes him to tear his own throat open, a death that the police cannot explain. This pattern makes him the recurring fifth victim of the village's supposed curse, and his inability to escape this fate across multiple timelines underscores the tragedy of his position.

His key relationships include his partnership with Takano, which is both professional and personal; his respectful friendship with Kyōsuke Irie, the clinic director; and his friendly rapport with the club members, particularly Mion and Rena, who treat him as a familiar visitor rather than a stranger. He also crosses paths with Detective Ōishi, who views him with suspicion. In the second half of the series, specifically in Matsuribayashi-hen and the later arcs of Gou and Sotsu, Tomitake survives the festival night by escaping with Takano, breaking his usual fate and playing a more active role in confronting the conspiracy. In these outcomes, he demonstrates combat competence, tactical awareness, and a willingness to protect Takano even as he begins to understand the scope of her actions. His development moves him from a recurring victim to a reluctant survivor who must choose between duty and humanity, though his gentle nature and loyalty remain constant.