Kodama is a young boy who appears in the episode titled The Sleeping Mountain. He is the apprentice of Mujika, an old mushishi who acts as the guardian of a mountain. When he was very young, Kodama was abandoned on that mountain by his parents, who could not afford to care for him. Mujika discovered him there and raised him, training him to eventually inherit the role of mountain master.

Kodama is earnest, dutiful, and deeply respectful of the mountain and the mushi that inhabit it. His upbringing under Mujika has instilled in him a strong sense of responsibility for the stewardship of the land. His primary motivation is to fulfill the role his mentor has prepared him for and to maintain the balance of the mountain.

A central conflict arises when his parents, after losing their other children, return to reclaim him. This forces Kodama to confront a choice between the life and duty he has built with Mujika and the pull of his biological family. His key relationships are shaped by this dynamic: Mujika serves as a devoted mentor and father figure, while his birth parents represent a past from which he was separated.

In terms of ability, Kodama is a student of mushishi arts, learning to perceive and manage the specific mushi tied to the mountain. Unlike a wandering mushishi, his role is that of a stationary guardian, bound to a specific place and its spiritual affairs. His story arc traces his development from a foundling into a capable apprentice, ultimately leading to a moment of difficult decision regarding his identity and future.