Whoah this is awesome man! Not composition feedback, but the piece would harmonise better if there wasn't so much full saturation in the piece. Perhaps if you toned it down in a way to bring attention to his own saturation it would help. It's pretty but quite hard on the eyes. The way you've painted the body is looking really appealing
I decided to change the composition , in this version the character will be more understandable, also edited the character design itself. Removed the extra armor . Once I do the spirit of fire that huge armor is too much , perhaps will stop there for this version , I will try to work out . At first I didn't really know what I wanted to do for the contest .That's why I have such different sketches. Now I'm more confident about what I want to draw .
I think background wise you should use a different colour. It goes well with the fire but it throws the value balance of the piece out of whack and makes focusing on the fire a bit harder. Fire always looks better on a darker background of course, but that's one suggestion. Pose wise he's quite stiff, the gesture and action of his arms don't match that of his torso or legs and it looks a bit awkward - like he's fighting with his arms but his body is relaxed you know? The rendering is coming along though, and the armour looks super cool!