Nagi is a teenage boy who appears in a single episode of Mushi-Shi, serving as the client who seeks out the traveling mushishi Ginko. He lives on a small, remote island that feels somewhat desolate. Nagi is characterized by his deep concern for his childhood friend Akoya, who has recently begun behaving very strangely and appears to be suffering from a mysterious illness. His primary motivation in the story is to find a way to help Akoya, which leads him to request Ginko's expertise. Nagi is described as having short black hair and black eyes. His role in the narrative is that of a concerned friend who acts as the catalyst for the episode's investigation into the mushi-related affliction affecting Akoya. He does not possess any special abilities and undergoes no significant personal development beyond the resolution of the immediate crisis. His key relationship is with Akoya, and his willingness to reach out to an outsider demonstrates his bravery and devotion to her well-being.