Line art is great. I like the texture of the skin, although it still needs some cleaning up( the way in which you clean it up is totally up to you, so you will be hearing no words such as, AA it a little more, or more dithering in this region, from my mouth). I'm not liking his head though. It looks odd, almost babyish for an adult. It's tad small. It can most definitely be solved by just elongating the mandible, and lower jaw area. That, plus his mask must be on a little tight, cuz if my mind serves me right, MK ninja masks don't ussually show their foreheads the way you have portrayed it. I'd suggest to either lower the mask from the top, or raise the eyes and brow a little higher.

   My main point to digress to you, however, is the pillow shading of the yellow square designs, and his clothes, and mainly throughout his body. It's not necessarily a bad thing, but at this website, it is definitely frowned upon as laziness. So please, make an effort to learn proper lightsource shading, dithering, or AA'ing to make it a smidge easier on our eyes. Other wise, its a great piece to behold. Great job...