Wow!

That's pretty sleek looking. When you mentioned that you colored something from the manga I was thinking,
"Oh no... This can't be good!" but I'm actually pretty impressed, especially with how smooth the lines look.
I can see a handful of issues that would make the piece even better if corrected. The first is light-source. I realize that Roy is surrounded by light-bringing flames from every which way, but if you pick one certain angle for the light to shine from, the coloring will look a lot stronger and definitely more unified. Right now, you have two key areas of light focusing on the right side of his face, and the left side of his torso. These areas are almost completely unrelated, and cancel each other out, you might say. If you pick one or the other, and then alter the rest of the picture to follow that pattern of lighting, you'll be in good shape.
I would also suggest you go darker with some of the shadows, especially in places where things are overlapping or remain untouched by the light source. The creases in his cape, the joints of his armor, and the shadow his chin would presumably leave over his neck are all good places to start. (But again, don't just throw in shadows for the heck of it; light source!)
Finally, it looks like you're kind of bouncing back and forth between soft-style coloring (ex:
here ) and cel-shading (ex:
here). Picking one or the other would add consistency to the coloring. To be honest, I would consider cel-shading. You have the
perfect lineart for it. I'm jealous.
