Kohroku is a supporting character in Princess Mononoke who works as an ox-driver and cattle herder in the industrial settlement of Irontown. He is introduced primarily as the husband of Toki, a strong-willed female worker in the town's ironworks. Kohroku represents the ordinary human laborers who are caught in the escalating conflict between Irontown's expansion and the gods of the forest. In terms of personality, Kohroku is generally friendly and good-natured, but he is defined by his extreme timidity. He is notably cowardly and easily frightened, with his most prominent fear being the Kodama, the small, harmless tree spirits that inhabit the forest. He is not portrayed as particularly intelligent or brave, often providing comic relief through his nervous reactions. His simple desires for a peaceful life and his open adoration for his wife Toki, who often finds him exasperating, ground him as a relatable figure amidst the epic struggle.

Kohroku has no grand motivations that drive the plot. He follows the orders of Lady Eboshi and hopes to avoid danger. His critical role in the story occurs during a journey where he accompanies Lady Eboshi and a group of men transporting goods. The caravan is attacked by San and the wolf clan. During the ambush, Kohroku is wounded and ends up helpless in a river. He is eventually rescued by the protagonist Ashitaka, who carries him back to Irontown for treatment. This event highlights Ashitaka's peacekeeping nature and Kohroku's vulnerability. Beyond this incident, his character does not undergo significant development or change; he remains a symbol of the frightened, common person caught in a conflict far beyond their control.

Kohroku possesses no distinctive special abilities or combat skills. His function within the story is thematic rather than active. By embodying the fear and simplicity of the average citizen of Irontown, he contrasts with the boldness of Lady Eboshi and the ferocity of San. His terror of the forest spirits underscores the profound cultural and spiritual disconnect between the encroaching human industrial world and the natural, spiritual realm of the forest gods, illustrating the human cost and confusion present in the film's central war.