Marrying the Better Beastman

In my previous life, my parents doted on my frail, sickly younger sister. For her sake, they chose a hawk beastman willing to settle in a human city as her husband. Me? They cast me into the deep sea, marrying me off to a giant shark beastman. When the apocalypse came and torrential rains drowned every human city, my parents and sister were left clinging to a rotting plank, adrift on the endless ocean. I couldn't bear to watch them die. With my giant shark husband, I dragged them down into the deep sea to safety. But resentment festered. Seeing me live comfortably while my shark beastman hunted day after day, my parents grew furious that my sister's life paled in comparison to mine. In their jealousy, they laced the fish we ate with poison and killed me. Now, given another chance at life, they've decided my sister should marry the giant shark beastman instead. My biased parents believe she will finally enjoy the blessings they once denied her. But what they don't know is this: after the cataclysm, fish become scarce. And a giant shark… does not survive on scraps. He needs flesh.