Boo's brother, Mr. Nathan takes the place of their father when he dies. But is he Boo's protector—or jailor? And why does he fill up the knothole where Boo leaves gifts for the kids—does he want to keep his brother from making connections with the outside world, or just prevent him from getting hurt by thoughtless children?
He does seem to see his yard as his own live-action version of Grand Theft Auto. When Jem, Dill, and Scout sneak up to the house at midnight trying to catch a glimpse of Boo, Mr. Nathan meets them with a shotgun blast. On the other hand, he helps save some of Miss Maudie's possessions when her house catches on fire. Though we see more of him than Boo, Mr. Nathan is just as much of a mystery.