Minor Characters in a Story

Fiction encompasses a very broad spectrum of literature and every writer of fiction goes about it in his/her own style. Stephen King writes differently from Danielle Steele who in turn writes differently from Isaac Asimov. Yet all works of fiction share some common denominators. There are protagonists ("good guys"), antagonists ("bad guys"), setting, plot, etc. And, in nearly all cases, works of fiction feature minor characters. While these characters, by definition, are not the focus of the story, they do have a purpose in the story and serve what turns out to be a vital role.
What is a Minor Character?
A minor character is one who is not entirely important to the plot. That is, the story would still hold together without that character, but might be a little choppy. In a story such as "Jane Eyre," Bertha Mason, Edward Rochester's first wife, is a minor character. In a totally different story like the Star Wars movies, Yoda plays a major role in the fifth Star Wars film, "The Empire Strikes Back," yet he is just a minor character in the sixth film, "Return of the Jedi." As these two examples illustrate, a minor character is responsible for one of two roles in a story: character revelation or plot development.
Character Revelation
Except in some of the most long-winded stories, a work of fiction focuses on a short period of time. We, the readers, are then forced to make judgments about the various characters based on what we observe. But this often does not do enough. We assume a character is good or bad, but we seldom truly know. Even less often do we know why. In "Jane Eyre," we know that Jane loves Edward Rochester, and we know that he loves her, so why then does he only want her as a mistress? And we also wonder why he seems to be very close about certain life details and his dealings with others. Then it is revealed that he is already married to a woman who is violently insane. Thus we find out his true character. We learn that he is a