Heh, had a few thoughts.
Hero - ish
Pan
The ancient god, amused by Diana's antics, has come down from Olympus to get a better view of her at work. Now officially a member of the League, he fancies himself a superhero as well as a god- though there are leaguers that disagree. Mostly he just lounges about in whatever HQ he happens to be in at the time trying to get female leaguers to have sex with him instead of doing something actually heroic. Usually interpreted as sloth, part of his apparent laziness is a due to a genuine belief that the time to worship gods has passed and he's staying out of the spotlight as much as he can.
Still, one of his powers is the ability to heal by touch- to the point it can regenerate limbs, cure diseases, undo birth defects, and even resurrect the very recently dead. He may not be the most active member of the League- but you can't say he doesn't pull his weight in the medical bay.
Villain
The Tiger Shark
An Atlantean Supremacist to his core, The Tiger Shark is a terrorist pure and simple. Notably, he can breathe underwater, swim at speeds faster then any ship to date, and between his superhuman strength, durability, and his martial arts prowess he's considered a better fighter then the vast majority everyone else. How good is unknown exactly- he's better underwater then on dry land and he can certainly defeat his main adversary Aquaman in a straight fight and might be a Wonder Woman class fighter as well.
Dedicated to Atlantean supremacy, he only thinks surfacers are good for two things- food and sex slaves. Air breather woman, admittedly, have an exotic quality to them that he likes. Usually he expresses this by combing beaches and raping an air breather when he feels horny and can't find an Atlantean partner.
