Love Has Become the Robbery of the Phoenix's Wife and the Dragon's Husband

When there are only two beasts with divine power left in the world, a love story ensues. But he didn't expect that after leaving without saying goodbye, love would be stained with sadness, and the bloodline of the mythical beast would be wiped out. At this time, he is a human and she is neither a human nor a monster. Can the eternal love end well? Can love as deep as the sea be exchanged for staying together forever?