Eragon Theme of Good vs. Evil

You want an epic struggle between two opposing moral poles of the universe? You've come to the right place. Eragon is more than just the story of a fellow and his dragon. They find themselves in the middle of a war to turn back an evil tide of monsters and magicians. It's not just a morality tale of rock 'em, sock 'em robots, though. Along the way, our hero must confront what it means to be evil, and how hard it is at times to be good. We think that he's a better hero for it, though, which makes him even good-er in our eyes! (Er, better…we meant better.)

1. Does King Galbatorix have any other motivations than just to bring evil to the world? 
2. What do you think of Murtagh's beheading of Torkenbrand? An act of good? Evil? A bit of both? Explain. 
3. Would Eragon be so…good, if his foes weren't so evil? Does Eragon depend on the existence of evil in order to do good? Why or why not? 
4. Is Durza the Shade a purely evil character? Since we get a wee smidge of his backstory when Eragon enters his mind, does that explain some of his evil actions to you? Or is he just a bad baddie, through and through? Why?