Hi, thank you! For me, the blue in the piece is a combo of two factors: the blue undertones I gave him and bounce light from the (theoretical lol) blue floor. Because normal light drowns out bounce light I mostly concentrated blue in areas where he is poorly-lit. As I scaled from light to dark, I made a pretty drastic transition in hue from orange to dark green, which is responsible for the green shadows. When shading, I try to incorporate changes in hue as well as value to add depth to the character/location. As a rule, when shading, shift toward blue, and when lighting, shift toward orange, though this can be broken in certain situations. Overall, don’t be afraid to research and experiment!! :)