This narrator knows all the whozits and whatzits, and to top it all off, time and space is of no concern to them. In one moment we're smack dab in the middle of a Shad and Jeth hangout, and then all of a sudden the narrator busts out with "[Jethro] would remember the rebuke to the end of his days" (4.115)—which at ten years old, is presumably a lot of days. (We've got our fingers crossed for ya', Jethro.) In other words, that's quite the time jump our narrator makes.
But Jethro isn't the only character the narrator seems to know a whole lot about it. When Jeth goes to mail his letter to Lincoln, we get a glimpse into the private thoughts of the old man who throws him some shade (9.153), and the same goes for Matt and Ellen when we're told how "unconsciously they clutched at [Jethro]" (12.33). The narrator is able to pop into any character's head as it suits the telling of the story, and the end result is a complex portrait of how one community navigates the tricky terrain of the Civil War.