Kamizono Mizuki

The little sister of Tsubaki. She has always watched her older sister deal with hardships for her so she thinks of ways to repay her someday.

Recently, she started dating her coworker Fujiki Kei, but their relationship remains pure, and so she's still a virgin.

Seeing her sister act strangely, she tailed her and discovered that she's working at "Ubai", and with this turn of events, she decided sell her body as well.