How to Date a Top-Tier Merman Omega

[Future world] + [ABO] + [Two strong leads] + [Two male leads] + [Sweet romance] + [Mutual salvation] + [Happy ending]

You were like a god from the heavens, falling into my galaxy. From that moment on, my galaxy was filled with light.

Author's note: The protagonist is a merperson, and merpeople can change sex. They aren't each other's first, but this is a one-on-one romance.

The protagonist's growth is a major part of the story, and there are angsty moments, so proceed with caution.