In fact, the first example of his character is revealed in the very first paragraph. ... Jem is four years older than Scout. This means that while he is a playmate, he often serves a parental role too. ... Dill is an interesting character because his personality is a compilation of many of the story's other characters.
It becomes an adverb, because if you think about it, you're adding something to the meaning of the word! <u>Definition of: Adverb:</u> A word or phrase modifying an adjective, verb, adverb, or word group!