I Crowned Myself with His Shattered Heart Stone

Betrayed and sacrificed to the sea by her former lover Silas, Elena is saved by Lucius, the Sea King. They fall in love, but Silas attacks their underwater kingdom and murders Lucius. Captured and pregnant with Lucius's child, Elena endures assassination attempts and humiliation. Awakening her latent powers, she exacts brutal revenge on her betrayers and returns to the ocean to rebuild her home, crowning herself the new Sea Queen.