Heartless: Imprisoned by the Mad Merman

I once bought a dying merman from a black-market auction. Then I bound him to me with a forbidden Siren Pact, cut out his heart, and used it to save my brother. I thought he would heal. So I threw him back into the ocean and never looked back. Years later, he returned as Levian, the ruthless ruler of the deep sea. He had no heart, but our bond was still alive. He dragged me into his underwater kingdom and swore I would never escape him again. I pretended to give in while secretly planning my escape. But when mutant sharks attacked, he risked his life to protect me. The moment I finally reached the surface, he caught me. And just as he swore I would belong to him even in death, a human warship appeared—and a harpoon tore straight through his body.