After We Swapped Beast Transformation Potions, I Became a Snake Woman

My father forced my older sister and me to swallow demon cores. My sister became a beautiful, fertile snake woman, while I became a mermaid who could bewitch people's hearts. After we transformed into half-demons, my fertile sister was sent to the harem of a Regent who had no heirs. Proud and aloof, she met a tragic end there. I, with my sensitive nature, was sent to the Star-Seizing Pavilion and made a plaything for the powerful and influential. In the end, I died with my eyes still open, and my body was dumped in a mass grave. When we opened our eyes again, we had returned to the day we were fed the demon cores. Tears in her eyes, my sister gripped my hand. “Let’s switch places, little sister. You’ve always been quick-witted, so you can surely carve out a place for yourself in the Regent’s treacherous harem. Leave those powerful nobles to me!” I gladly agreed. In this life, my sister and I would join forces, and everyone who had caused our deaths would get what they deserved…