I want to say that the author uses Character A's "character development" to explore Character B.
In other words, the author builds on the personality of A to exemplify the nature of B.
What is another word that replaces "character development" in the context above?
Obviously, there are a lot of words that might work, but I'm not sure if they are exactly what you are looking for:
Complimentary, contrast, juxtapose: All mean to compare, possibly opposing, elements.
Take a look at some of the language in this blog post referencing Robert McKee.
Hm, good question. Since you stated that one character’s development can explore another, then there is a synthesis, some symbiosis. I am not in reach of a dictionary, but if I could give an opinion instead of a real word in this case, I would say “commetamorphous” or “commetamorphicity”
The Latin prefix cum + Greek meta + Greek morphē
cum = with (this prefix implies more than one) meta = after (this prefix implies a timescale) morphē = shape, form, appearance
An obvious example is metamorphosis, which implies a change of form.
The only addition is cum which, by some laws of language I forget, changes to com- in the prefix. We now have a word to denote a change together (character α & β), thus they develop together.
In this case I would define as such:
Commetamorphicity: a character development method which uses one character to develop another.
I hope this helps (:
