There are alot of deserving candidates for this, MST's Atom and Byrd's Flash being the immediate to come to mind. But there's one character that's always probably been overlooked in the game, and it happens to be the most consistent in portrayal, quality, and an obvious respect for the lore of it's subject. And that's The Man of Steel, as portrayed by Spike. His ultimizations not only make sense for the game and the world he's been crafting for Metropolis, they're actually pretty far and away improvements to what's already there. Why wasn't Jimmy Olsen ever in on Clark's secret in the comics? It makes too much sense. Simple stuff that gets taken for granted, when it sets up a fantastic portrayal that reminds us what Superman really is - something that the current comics aren't doing a particularly good job of conveying.
Vandal Savage (Andy C.)
If there's one thing Andy's always been good at, it's setting up a bigger picture. And there was no more perfect instrument for realizing his obviously well-thought out goals than Vandal Savage. The one man with the balls to take on the entire Justice League openly and to their face, you see a supervillain in every sense of the word whenever Andy's Savage takes center stage. It's the kind of villain that forces the heroes to overcome impossible odds, and maybe even beyond, because up until the end, Savage was on top. The only scarier thought than that is imagining what would have happened if he'd actually won.
Best Character Development:
The Flash (Byrd Man)
There's not a whole lot to say about Byrd's Flash that hasn't been said already. Hell, I don't think a season's gone by where I haven't given him the Best Hero slot. But really, what it boils down to, and what Ultimate Flash has always boiled down to, is this - the heart. The Flash was known pretty heavily as a jokester and a goof, but in Season III, that changed pretty drastically. Bart's in a pretty dark place whenever his chapter closes, and it wasn't much better than that for the rest of the season. After some truly shocking twists and not just one, but two great versions of Ultimate Zoom for him to face off against, Byrd wowed again and again. Can't wait to see where he goes next.
Best Solo Arc:
Victory Has Defeated You (Spike_x1)
Spike's arc with Bane this season has not only been a unique turn for the character, but it's also addressed one of my primary complaints about the character in the comics - after he breaks the Bat, what exactly is he supposed to do next? Spike answers that by having Bane leisurely wave off the power he's gained and instead thrusting himself into every battle he can, hoping to recapture the drive that he had to send Bruce Wayne off of Wayne Tower. It's a cautionary tale for a supervillain - once you win, what good are you? And of course, with Spike's portrayal of Bane already pitch-perfect, it's an engaging and fascinating character study.
Best Multi-PC Story Arc:
The Justice League versus The Legion of Doom
As someone who decided to stick to his guns and opt out of having Bruce Wayne as Batman take part in anything for an entire season, I have to say that this arc was the closest I ever came to regretting it. Not only did it last from beginning to near end, but it built up to a point that made the eventual clash between the two teams all the more epic and seismic. On one side, you have a Justice League who's been morally drug through the dirt all season with a man down and no leader to follow. On the other, the confident and war-hungry Vandal Savage following his plan precisely to the letter, nearly taking the League down in one fell swoop. Had I been apart of it, I'm sure I would've had alot of fun pitting Batman against Clayface or Savage himself (or both, given they were at one point the same), but it was a terrific read regardless.
Best Post: In the end, Edward Nygma survives.
Yeah, just read that and tell me Nygma wasn't one of the most brilliantly executed characters in any Hype RPG history. Not only was it an ending befitting of a great criminal drama, it was something that genuinely shocked me when I read it. I actually didn't know what Byrd had planned for Nygma, figuring he'd either kill him or put him in an even higher position of power. But nope, his fate was actually worse than death. Even though should The Riddler come along in this continuity, it'll have to be someone else doing the puzzles, I am more than glad in knowing that at least Byrd's work of sheer brilliance (yes, I called him brilliant twice) with the character will remain untouched.
At this point, who else would it be? No one has kicked our asses harder, lent more moral support, contributed to more IC posts, or just generally kept the game afloat than Byrd. Hell, this is kind of redundant, at this point. The man is MVP for life, as far as I'm concerned.