It looks more like the airbrush was used when putting in the base colors and a hard brush to sharpen up some things such as the eyes, along with taking advantage of the background color as another color palette for the shading and lighting. Kind of like how the print industry uses the color of the paper as if it was another color to not waste ink. I personally like this technique and encourage people to try it. The style is fun because how experimental it is.
gerald said at SA"battle that he actually created shadows mind pure I guess his soul is pure but his black-doom blood make him also evil also in Sonic Battle rouge said that shadow's and Emerl's souls based on marias soul :3
It's "beautiful"...the spelling...it's spelled wrong. And last I check he was the bad guy in the series. The antihero. I like the concept, good shading. Paticularly my favorite part is the face, probably because it's the only part that's half finished.