Isokawa Sayuri

Protagonist's mother-in-law. She blames herself for her daughter's actions, and so she offers to take care of the protagonist in place of her daughter Akane.

Several years ago, she eloped with her boyfriend who then left her as soon as she got pregnant. She used to be a prostitute to provide for her daughter by herself, and was a top hostess back in the day together with the protagonist's aunt Fujino. Ashamed of her past, she wants to keep it a secret from the protagonist if possible.