Very nice design on this guy! I also really like the foggy atmosphere in this image; gives the pic a unique flavor. I think you perhaps could have cropped the image a little closer for a more dramatic composition, though this being more of a design image I understand that's not quite the point.
The hero: "Is it getting hot here, or is it just me?" *Fire collossus jumps up and singes the guy's beard and eyebrows with its roar* "HOLY MOTHER!...Ok, I guess it WASN'T just me." *Runs away, underpants smoldering.*
The general look of the thing resembles slightly that of the Hierarchy habitat walker from Universe At War (game).