I feel like there's something unnatural about the positioning of the characters. It might help to put yourself in the situation that you're drawing, if you're not doing it already. Be critical about what looks natural and what looks forced.
it looks amazing. I love the texture is there. The chains look really good. I think you should maybe lower the contrast on them a little so that they don't come forward as much as they do.
The ground plane they are standing on could be blurred alot so it doesn't look so sharp. The sculpting on the body of the larger fellow looks well done!. I can easily tell where my eye is supposed to go first aswell.
The knuckles on the hand holding the axe look like they aren't attached to the rest of his hand.
The bunching of fabric on the lower figure looks unnatural.
Again I love the way you rendered the chains but they pop a little too much for my taste. good work
The way you've done this piece is fantastic, I love the painterly feel to it.
Critique wise, the largest character's head seems to be chopped flat at the top - perhaps round the skull out more?
And you've given the piece nice soft lighting, but the chains seem to be lit up a bit too harshly compared to the rest. Maybe lower the contrast a tad and add some deeper shadows to the chain around the throat?
Anatomy wise, the right leg (on the shield) seems to be quite a bit shorter than the other one, and the top of the axe twists in a different direction to the base, as if the axe is slightly wonky (try rotating it more to the right to fit in with the hand & line).
These are all just minor things, and I really love the way you've done this, especially the style of colouring! :]
You could make the lighting more dramatic. Think about the cast shadows and where they fall on the characters. It's ok for parts of the forms to be hidden or implied. Areas in shadow will have less detail.
Very nice overall.
I want to echo some others' comments that the lighting seems inconsistent, like you couldn't decide if you wanted soft or harsh lighting in places.
The little guy on the big guy's shoulder doesn't feel like he reads right to me for some reason, I think it's the lighting difference between the arm and the hood-head, and stylistically, he seems painted a bit tighter than the rest of the image which makes him stand out more.
I think the axe is positioned awkwardly. If you just mirrored what you have and flip it the opposite way, it would look more natural.