My Sister Stole My Fiancé, I Married Poseidon's Son

In the mermaid kingdom of the Seven Seas, the colour of the egg a woman lays declares her bloodline. Sapphire blue means noble; pale grey means a sea worm, a half breed. Coralia Pelagios, holy maiden of the Moon Sea Pearl and betrothed to Proteus Okeanides, lays a grey egg and is thrown into the abyss. Her sister Pelagia admits she tampered with it. Coralia is reborn, and Proteus breaks the engagement in front of everyone and chooses Pelagia. With nothing left, Coralia goes down into the forbidden abyss and wakes Triton, a man with no tail, and joins with him. She lays nine dark gold eggs of a kind no record describes. The clan calls it mutation and demands that she and the eggs be destroyed. The tests she is given are rigged, so she carries the eggs to the ruins of the seal: if they resonate she is cleared, and if they do not, mother and eggs die together. Triton has been waiting for her for a thousand years, and who he is has not come out yet.