Demon Slayer Harem 3

Tamayo sat in her cell in the endless castle, awaiting whatever Mulan had planned.
Tamayo heard some footsteps and saw Daki entering her cell and laughed.
Tamayo: Oh my, Mulan's little toy, Kibutsuji. I wonder if this toy can do anything besides please the queen?
she said mockingly to Daki

Tamayo, 600 years ago, was a happy woman with a wonderful marriage and a loving family, but unfortunately she contracted an unknown illness and was near death. Before dying, Mulan Kibutsuji came to her rescue. The queen of demons offered her a deal: she would become a demon. Tamayo accepted without thinking of the consequences and became a demon, ultimately killing her own husband and son and becoming devastated.

She followed Mulan for 200 years, but after Mulan was nearly killed by the legendary demon slayer Yoruichi, she managed to break free and began working for the demon slayers to defeat Mulan.

400 years later, she was betrayed by her assistant and captured by Mulan; now she was imprisoned in a cell, awaiting her sentence.