Naoko Osato

Naoko is portrayed as a young Japanese woman and a student, raised as the cloistered heiress of a long-established household.

Bound by an overbearing father, Naoko keeps her feelings hidden and grows torn as an arranged marriage bears down on her, turning cold toward Gunpei even as her love for him endures. That devotion drives her to extraordinary and desperate lengths once tragedy strikes, from concealing his body to protect herself to clinging to him long after he is gone.

Naoko is the sole daughter of an affluent family that had brewed miso for three centuries, their estate tucked at the end of a mountain road on land they owned entirely. Her protective parents refused to let her live near her school in City S, next to Morioh, so a driver ferried her on the two-hour trip each way through all her years of schooling, and they intended for her to marry a man named Shuichi after graduation. Instead she fell for the family gardener, Gunpei Kamafusa, and hid the affair.

As the wedding neared she pulled away from him, and a quarrel ended with Gunpei fatally struck against a golf club. When his corpse would not stop bleeding and began to decay, a panicked Naoko hid the body and even drank his blood to keep Shuichi from noticing, storing him in her ceiling closet with the blood draining into a bottle she emptied each morning. Though lifeless, he seemed caught in an endless dying, his face briefly restored whenever water touched it.

Still in love, she conceived by his corpse and bore a daughter and a son, otherwise living contentedly with Shuichi, who believed the children his. Her secret finally surfaced when Rohan Kishibe read her with Heaven's Door during his research and uncovered that Gunpei had been possessed by the yokai Mutsukabezaka.