Tanyuu Karibusa is the fourth Scribe of the Karibusa family, a lineage bound by a unique and burdensome curse. Long ago, a destructive entity called the Forbidden Mushi was sealed within one of her ancestors, turning the woman’s skin the color of ink and leading to her death. The curse persists, resurfacing every other generation in a new host.

Tanyuu carries the Forbidden Mushi within her, its presence marked by a pitch-black stain on her right leg that renders the limb useless. Since childhood, she has relied on crutches, becoming adept at moving by hopping on one foot. Her duty as Scribe is to manage the Mushi sealed inside her. She listens to stories from Mushishi, particularly those filled with suffering, which draw the Mushi out. She then transcribes these accounts onto special scrolls, a painful process that seals the Mushi onto the paper.

Despite the pain and hardship the Mushi has caused her, Tanyuu holds a deep respect for all life, including Mushi. She dislikes tales that portray Mushi as vermin, preferring stories that treat them as living beings striving to survive. She especially values the empathetic narratives shared by the Mushishi Ginko.

Confined mostly to her home where the records are kept, Tanyuu lives in isolation alongside her guardian, Tama Minai, who has been with her since childhood and taught her to read, write, and perform her duties. As a child, Tanyuu struggled with both her immobility and the grim nature of her task.

Tanyuu is kind, proud, and efficient in her role—one she initially hated but grew to love. She often shows more concern for others than herself, regretting the suffering her curse has brought upon Tama and the Minai family. Her greatest wish is to fully seal the Forbidden Mushi, freeing herself from physical constraint and allowing her to travel with Ginko. In "Path of Thorns," she requests Ginko’s aid to help another named Kumado avoid reckless actions, mindful of the potential conflict between them.