He and he fell in love because they were both of the same sex. Homosexuals are people at the bottom of society. When their love affair became known, both Ran Yin and Ni Chen fell into the sea. Fortunately, they were still conscious, but Ran Yin could no longer find any trace of him...
He wants revenge, revenge on those who have hurt them, revenge on those who caused their death, and then he will "find" Ni Chen... And will never leave him.