What impression do we get of Macduff's son before he is murdered?

This is actually under the wrong heading but hey it's Shakespeare and I love his stuff. Maduff's son never gets a name. He isn't a major character however his discourse with his mother is pretty important. Basically the boy finds it odd that bad men are punished because there are more of them to "beat the good ones down." Well, the quote goes something like that. This is one of the larger themes in this play and the boy seems to understand it. The boy does other things like attack a murderer for disparaging his father. I guess you can say that he is feisty. His clever discourse with L. Macduff means he isn't stupid. I think that’s about it though; he doesn't get allot of stage time.