Ravus is the one who pulls Noctis out of the water instead of Gladio. He decides to keep him, because he blames Noctis for Lunafreya's death (on top of other things).

Not exactly sure what I'd like to happen in this hypothetical fic. I just know that I really, really enjoyed the part in the game where Ravus had the blade to Noct's throat and then choked him with his magitek arm. So, uh... more of the same would be excellent.