Protagonist
Scout Finch
Scout tells the story, but that by itself isn’t enough to make her the protagonist. She also
is the story: while many of the novel’s major events happen around her rather than to her, it’s her coming-of-age that brings these events together into a narrative. Other characters also develop and change over the course of the story – Jem, Atticus, even Aunt Alexandra – but the novel keeps coming back to Scout, and how these changes affect her own path towards adulthood.
Antagonist
Bob Ewell
Ewell is nasty. He doesn’t have one redeeming characteristic. While Mayella is the one whose actions first get Tom into trouble, Ewell is the one who makes sure that that trouble snowballs into a court case, conviction, and execution. Even after the case is over, Ewell keeps going after Atticus, Judge Taylor, and Helen Robinson, and finally almost kills the Finch kids. Heck Tate probably wasn’t exaggerating when he said the ladies of Maycomb would bury Boo in cake for taking Ewell out: this guy is bad news without a glimmer of good.
Guide/Mentor
Atticus Finch
As their father, Atticus is supposed to provide guidance to Jem and Scout, but he does an exceptionally good job of it. He isn’t afraid to speak honestly to his kids, and even explains what rape is to Scout when she asks. Atticus not only talks to his children about what he wants to teach them and why, he also tries to provide a good example to them in his own conduct. In practicing what he preaches, Atticus shows his kids that such behavior is not only desirable, but possible. And as the ethical center of the book, Atticus gives the reader a moral compass with which to navigate the shifting sands of Maycomb values.
Foil
Tom Robinson/Boo Radley
At first glance, Tom and Boo seem very different: one lives with his wife and children among friends, the other lives in isolation with his taciturn brother. One has his fellow churchgoers take up a collection on his behalf, while the other has no one think much about him except some curious kids. But dig deeper, and Tom and Boo start to look more similar: both are disabled in some way (Tom’s crippled arm, Boo’s crippling shyness), both are innocents with a bad reputation, and both are compared to mockingbirds. Perhaps most tellingly, Tom and Boo both serve as scapegoats for their community, being blamed for things they didn’t do. As foils, they reveal less about each other than about the community they live in, and suggest that the people a community includes say less about it than those whom it excludes.