Adashino practices medicine in a seaside village. He possesses a tall stature, fair skin, short spiky black hair, and dark eyes, consistently attired in a dark yukata and monocle. His primary pursuit is collecting mushi-related artifacts, stored in a shed behind his home. He sources these items from various places, including periodic meetings with Ginko, from whom he persistently requests to examine or purchase unusual and potentially dangerous mushi objects, undeterred by the risks.

A long-standing friendship connects Adashino and Ginko, defined by their contrasting perspectives. Adashino focuses outwardly on accumulating possessions, opposing Ginko's minimalist, itinerant existence. This divergence extends to their philosophies: Adashino exhibits emotional excitability and a desire for ownership, differing from Ginko's detached, Daoist-aligned approach to life and mushi. Despite these differences, mutual acceptance sustains their bond. Adashino knowingly engages in transactions with Ginko, aware some items might be misrepresented, yet he values even questionable acquisitions. Their interactions reflect a shared understanding of individual perspectives, evident when Adashino acknowledges that becoming mushi could represent happiness for some, aligning with Ginko's respect for personal choices regarding mushi encounters.

During the story involving a solar eclipse and the Hihamukage mushi, Adashino appears alongside children in his village at the narrative's beginning, though he plays no central role in resolving the eclipse events. The visual contrast between Adashino's monocle, representing reflected light or yang, and Ginko's covered eye, symbolizing darkness or yin, underscores their complementary natures within the friendship.