My Mate is Promordial

Nereis, Poseidon's daughter, inherits her mother's beauty but none of the sea gods' power—until her fiancé Triton humiliates her publicly by choosing a mortal over her. Heartbroken, she returns to find a mysterious dark golden egg from the abyss that only bonds with her. Named Ose, the egg hatches into the ancient Primordial Sea God, her fated protector. But when a thousand-year-old revenge threatens to drown the deep sea in chaos, Nereis must awaken her hidden pure-blood legacy, and Ose will make a sacrifice that spans three thousand years.