How My Beloved Older Sister Married Into A Family Of Doms And Became A Masochist... Yui Hatano

My sister married into a very wealthy and prestigious family. She raised me like a parent, and I caused her nothing but trouble. So I wanted her to be happy after marriage. But... We were close, contacting each other many times, but after the wedding, there was no word from her. Worried, I went to see her. No one was in the mansion. I snuck into a room with an open door and found a DVD. It was labeled 'Female Slave ● Impregnation Record.' I had a bad feeling...