Flamelord said
Actually, wait, I don't really know M:tG mana or what have you. Forget I said anything.
This is the basic idea. It gets more complex as you start mixing colors and considering game effects, but it's not a terribly difficult concept. One of the most common misconceptions is that any color or color combination is inherently good or evil. There are White villains and Black heroes (though the opposite arrangement is more common).
Raineh Daze said
No, no; he isn't. He might act that way, but that doesn't describe him--or Unlimited Blade Works--any more than Green does.
Mechanics related to summoning and artifacts are Blue. He's definitely at least partially Blue. I don't know enough otherwise to assign any other colors.