After We Swapped Beast-Transforming Potions, I Became a Fertile Catgirl

My sister and I were both forcibly made to drink a potion by our father. My sister became a pure and lovely cat-woman, while I became a bewitching fox-woman. After we turned into beast demons, my sister was sent to the harem of an emperor who could never have children. Strong-willed as she was, she died at the hands of the harem concubines while heavily pregnant. As for me, with my sensitive nature, I endured endless humiliation before dying a miserable death. When we opened our eyes again, we'd both returned to the day we were given the potion. My sister grabbed my hand. “Let's switch potions. You're always so clever. You'll surely survive the treacherous harem. Leave those stinking men to me.” I nodded. In this life, it was our turn as sisters to turn the world upside down...