Ginko travels as a mushi master, investigating supernatural phenomena caused by primordial lifeforms known as mushi. His appearance features white hair, pale skin, and one green eye—a transformation from his original black hair and dark eyes caused by a childhood encounter with a mushi called Ginko. This event also rendered him a beacon for other mushi. Previously named Yoki, he possessed an innate ability to see mushi even as a child. After a landslide killed his mother, he was rescued by the similarly pale-skinned, white-haired mushi master Nui. Both were later consumed by a darkness-like mushi named Tokoyami. To escape, he sacrificed his left eye and memories, adopting the name "Ginko" as it was the sole word he recalled. This incident cemented his perpetual mushi-attracting condition, forcing him into constant travel to prevent dangerous accumulations near settlements. He deters mushi with special repelling tobacco and maintains a transient existence, seldom revisiting locations.

Ginko exhibits a generally laid-back demeanor but shifts to intense focus when confronting mushi-related threats. He approaches cases by emphasizing mushi as neutral components of nature, integral to ecological balance. His methodology prioritizes observation and minimal intervention, presenting affected individuals with risks and benefits before they decide their path. For instance, during a solar eclipse caused by a sunlight-blocking mushi named Hihami, he diagnosed the phenomenon while mediating a conflict between two sisters—one avoiding light due to a skin condition, the other resentful of her sheltered life—facilitating family communication to resolve tensions alongside the mushi’s effects.

Throughout his journeys, Ginko intermittently encounters figures from his past, such as his friend Adashino, but sustains no lasting ties due to his nomadic life. His backstory includes apprenticeships under various mushi masters; one involved accidentally disrupting a mountain ecosystem by mishandling a mushi egg, reinforcing his grasp of ecological consequences. Despite occasional melancholy over his rootlessness, he accepts his role in studying mushi and aiding communities. He consistently acts as an investigator and advisor, departing once situations conclude. His modern clothing—an intentional design choice preserved despite the series’ historical setting—visually distinguishes him from others.