Okinu, also known as Kinu Himuro, began as a sacrificial offering in a ritual that failed to soothe a volcanic mountain. This catastrophic event bound her to the terrain as a jibakurei—an earth-confined spirit—for nearly 300 years. Her spectral isolation ended when she encountered Reiko Mikami and Tadao Yokoshima at a mountain hot spring, leading her to join their Mikami Ghost Sweeper Office as an assistant. She took this role to fund her own exorcism, accepting a scant wage of 30 yen. Despite her ghostly existence, she radiated a gentle and compassionate nature, distinct from her peers. Yokoshima nurtured romantic feelings toward her, which she returned solely as platonic affection.

A pivotal shift unfolded when her preserved physical body was unearthed, enabling her resurrection as a human. Even after regaining mortality, she retained spiritual gifts: healing powers and an intuitive grasp of spirits’ emotions, which later bloomed into innate necromancy. Post-revival, she also gained astral projection abilities, unusually maintaining physical interaction with objects during these out-of-body states. Her journey traces a transformation from a tethered spirit to a revived human, forever balancing the mundane world with her enduring ties to the supernatural.