What do you think of my skin concept? (Count Kha'Zix)

http://i.imgur.com/4O1zFLL.png

Hello, I've recently started to make some drawings of many things, including skin concepts for LoL champions. I've previously drawn Bilgewater Lulu before (but I've never posted it there) but now I feel the need to post my most recent skin concept: Count Kha'Zix (same series as Count Vladimir)

What do I need to do to make this drawing better? I don't know how to make shadings yet. I actually don't do shadings on any of my drawings. I have friends who don't even draw that much and they can already make shadings on their drawings. Is there anything else I need to improve?

Also, what do you think of the concept itself?