This boy is so mysterious with his black mask and colorful red and black clothing! He stands beneath a large building that is cast in shadows, adding to the feeling of mystery around him. I think the best way to approach this coloring page would be to keep the same colors for his clothing, with the pops of red from his sweater and the black mask. The rest of the picture can be accented using cool colors like blues and purples. We can give the building a navy blue hue to emphasize the shadows and then add a light purple to the sky to contrast it. Finally, I think it would be great to give his eyes a bright green color to really make them stand out against all the blacks and reds.