I bet itís a quick sketch you did, at least I guess it because I see some double lines when youíve made his shorts, but letís not focus our analysis on this pointless factÖ
This portrait of Knuckles is very nice for our eyes, thanks to two points: firstly, Knux looks handsome and styled with his mature and serious face, and his hair blown by the wind that prevents an eventual static position. And secondly, the magenta shades are, to my mind, the main reason of the success of this work: so many variations, from the light color for the lighting reflects, to the saturated color for the darker parts, have created important and pleasant effects of volume on the character and the background. I especially like the top part of Knuxís body, where the volume effects are more worked.
As a conclusion, itís amazing how you can turn a sketch of a character (that would look plain with only the pencil lines) to a beautiful work we enjoy ^^ I also love your style of creating reflects and volumes on characters, and I know Iíll quote this quality more than once in my future comments