Appearing early in the narrative, Charles Baker "Dill" Harris is described by Scout as "a curiosity" because of his attire--blue linen shorrts that buttoned to his shirt, certainly in contrast to Scout's overalls.  He intrigues Jem and Scout because he has seen the movie Dracula and can retell its plot to the point of "reduc[ing] it to dust."

An impish character, Dill instigates much of the mischief in which the children partake.After hearing Jem's description of Boo, Dill suggests that they try to get him to come outside, betting Jem The Gray Ghost against Jem's two Tom Swift's adventure books.  Later, he dares Jem to go onto the Radley porch.

But, for all his bravado, Dill is insecure because his mother seems uninterested in him as she and her husband close doors on Dill when he is home, or she sends him to stay the summer with his Aunt Rachel. In fact, Dill runs away one summer when he does stay home because his mother ignores him.  

Dill is extremely imaginative; Scout describes him in Chapter 14, 

Beautiful things floated around in his dreamy head.  He could read two books to my one, but he preferred the magic of his own inventions.

While he does not consider the feelings of Boo Radley, the "haint," and dares Jem to do dangerous things, Dill is truly sensitive.Dill's heart is certainly tender as he promises to marry Scout when they grow up, and he is sensitive to the injustice done to Tom Robinson.  In Chapter 19, Dill is "thin-hided" as Mr. Dolphus Raymond calls him because he cries when he witnesses Mr. Gilmer's cruel cross-examination of Tom as he insinuates that he has "had his eye" on Mayella, calls him "boy," and twist Tom's testimony, implying his effrontery at feeling "right sorry" for Mayella. He tells Jem,

"It ain't right, somehow it ain't right to do'em that way. Hasn't anybody got any business talkin' like that --it just makes me sick."

Above all, Dill is a caring person, a loyal friend to Jem and Scout.  In Chapter 23 when he learns of Bob Ewell's threatening behavior, he suggests that Atticus have a gun; then, when Scout disabuses him of this idea, he suggests that she and Jem mope around so that Atticus will ask them what is wrong. And, this suggestion works because Atticus inquires of the children the reason for their depression, and afterward, he explains to the children why Bob Ewell says what he does.

Imaginative, sensitive to others, and loyal, Dill is essentially a good boy, but he sometimes instigates things that can harm his friends in his efforts to seem brave and worthy.