Good call. Didn't even occur to me. Heh.
I see you gimped it in.
But it should be a drawn string back to his right hand. I find that a white string with about 80% transparency usually looks pretty good on most backgrounds.
Btw, you're getting better at these as you do them. The Behir looks really good.
I do have a suggestion that you might want to try out though. Your shadows are getting better, but I suspect that the black bases on the tokens is causing trouble. If you take a piece of white paper, cut a slit in it and slide the mini into it (base below the paper) you'll get an image that's easier to edit out the black bases. Then you can apply a drop-shadow with gimp and it won't be so dark.
Keep a couple odd shapes of paper around and you can quickly mask out some black pieces that show through. Of course you don't want to spend all day masking out the base, but a little time spent doing that will save you some time in you editing software.
1) You could also quickly brush on some white-out on the bases. It's non-permanent and should come off with a toothbrush after you're done taking the picture.
2) Roll out some thin white playdoh, and press it onto the black bases as necessary. You should be able to shape it pretty quickly with a toothpick and get a cleaner shot with softer, easier to remove shadows.