I'm liking this thus far, the foreshortening and the flames both look sound.
My only real concern right now is whether or not this looks like Zuko. But I think Zuko is hard to place sometimes if he doesn't have his characteristic scar or hair cut (whether the shag or the ponytail) then he's almost unrecognizable. Maybe putting his Fire Nation crown on might help?
The forehead also looks maybe a little too proud -- maybe you could try bringing down the hairline, even just experimentally.
And I could make a suggestion for the shadowing? One word: Chiaroscuro. I think that' would really work well given to the atmosphere and the bright intensity that naturally comes to flames.
mind blowing !! i can see that its coming out very nice!! the fire thing rocks !!keep it up. hey i would like you to join and share ur work on my art network as well if u like www.blastingart.com do check it out