Just so you guys know, emptiness is not necessarily a bad thing. If you have it balanced right, negative space can be quite striking in a medium where everything is cluttered.
Here is a good example of simple, visual balance:
This doesn't need anything else because the image on the right is interesting in itself. I think the issues you have are twofold: 1) the balance isn't there yet, 2) you're not quite sure what you want to do with this wallpaper.
In reverse order, you have no unifying visual idea. Kenshi and Brolli, while interesting characters in themselves, don't really jive together. Unless you're creating a parade of anime badasses, in which case you should title the work in a way that suggests that. So balance and direction can be immediately addressed by removing either Kenshi or Brolli and focusing entirely on one or the other. I think Brolli works best in this case, as the firelike texture you've created reminds me of the DBz power-up flames. I'm not sure what the Brolli pic looks like un-cut, but the image might be stronger if it remained in it's regular form. Then adding smaller Brolli pics, possibly of his whole body, might be a nice balancing element. That's all I can think of at the moment. You know better than anyone what it is you want, just find out what that is.
I believe it's spelled "melee" as opposed to "mellee." Unless you're going for a stylistic thing.