This one is my absolute favorite rendering of Shadow...aside from that digital version I have uploaded on here too.
Note: I did use a reference point to get Shadow in the pose he's in, though I do not know who the real artist is.

Although the name says 'Raphael' there to the bottom right corner...his name is actually Shadow, just to clarify.
Don't know why I put that name there though...

If you read his earlier description, you'd know he is the dark 'twin' brother of Riku, just a difference in his hair...and well the tail and wings...supposed to be with skin tone too, but I guess he was a little more light deprived when he posed for this picture. xP

Anyway...done with ultra-fine point black sharpie, and a red marker..highlighter..thing.