While her elder sister named Asa was a model, who got many love letters, Sayo was so shy and sick that she could hardly attend school. She’d feel jealous, as Asa would boast about her love letters and ask her to burn them with the brazier that always stood next to her in bed, after reading them, since their parents were strict over her. One day, she learned from a letter of Asa’s favorite man that she would have to marry someone her parents decided if she doesn’t meet him, but she burned the letter and remained silent. As a result, Asa became sad, and Sayo died of sickness by the time her sister got married. Her spirit lingered in the brazier, as she regretted her gesture, and she could appear when charcoal is burned in it. By the time Asa became a mother and saw Sayo’s spirit by using the brazier, she did not feel scared and would keep on using it every winter to see her sister, who would always ask her if she was happy.
Years later, her grandniece Himoto found the brazier and gave it for free to Rinne, since it tended to fall over when it’s not used for burning charcoal. Rinne and Sakura listened to her story, and since his sister passed away, Rinne used a Thought Blotting Paper to accumulate all the thoughts of her sister that were attached to the brazier, and a spirit of an elderly Asa emerged admitting that she did suspect Sayo but felt bad about having boasted to her before, and so Sayo could pass on.
- Like the Hot Water Bottle Ghost, she had a connection with the grandparent of a Sankai High Student and lingered in an item that can get hot, and appears in the final chapter of a volume.