I like this. Has potential. I made an edit here which mostly targets anatomy/balance issues.

If you don't do it already, I highly recommend frequently doing a horizontal flip on your work when drawing figures to make sure they're in balance. Looking at something from your comfort zone for too long in drawing makes it difficult to discern errors like these.

The main issue I saw with the anatomy was the connection of the arms to the torso. What I've added in the edit is that muscle (bah, I should really learn proper muscle terms) between the neck and the shoulder. It's fairly evident when holding your arm up like that. Where you had just a straight neck, I added in that little bump which roughly looks like the what I'm referring to. For the connection underneath the shoulder (armpit) to the torso, I can't exactly explain it in words, but hopefully you can see what I've added. Take a loot at this photo ( http://images1.comstock.com/Imagewarehouse/GS/SITECS/NLWMCompingVersions/gs215/gs215003.jpg ) for a good reference for the armpit and all since my edit doesn't show it off all that well. I also shifted up the position of the sword-wielding arm's shoulder. Don't mind the bulkiness. Feel free to tone it down, that's just due to my sloppiness while editing.

Back to the balance issue: yours has the guy standing in a diagonal line, in which case it appears that he should be falling on his back. Mine's still not exact, could be shifted a bit more backwards, but I basically straightened out that invisible line the figure is based on. It's good to flip the image like I said for solving these problems.

So, yeah. I'm no expert with this stuff, but I hope you can at least be pushed in the right direction with this for those issues by checking some references yourself. I look forward to the finished piece.