I just got a Shifts review which was kind, but which also took me to task for not developing Snape as fully as I developed Peter, and it set me to thinking about the issue. The truth is, I didn't especially develop Peter--he's got a backstory quirk or two, and that's about it--but, yeah... I gave him more page space than I gave Snape, and more motivation.

Why?

It's not that I don't have Snape backstory. I did a fairly extensive one for him in Of A Sort and "Invisible." But I didn't bring it into Shifts at all. Nor do I believe I should have.

Not every character in every story can or should be fleshed out. When the character is peripheral to the story (as Snape is to Shifts), spending time on developing him beyond tics develops expectations that aren't going to be met. While Snape's ambiguous morality annoys Remus (the POV and central character in the story), it's not something that comes into play as a plot point. Snape has several appearances in the story, mainly doing precisely what he did in OotP, but they're strictly plot points, not points of serious character interaction, for the simple reason that Snape isn't present for any pivotal moment in Shifts (except in spirit after the conversation about the Pensieve incident, at which point Remus duly thinks about him). Peter uses him to try and drive a wedge into the Order by goading Remus, but that's about Peter and Remus--and, to some extent, Dumbledore--more than it's about Snape. Snape just isn't there. Peter has more of an impact on the plot. Heck, Narcissa has more of an impact on the plot, and she gets less development than Snape, because Remus doesn't feel any need to angst about her at any time.

So, say I went in and started randomly dropping things from the backstory I made up for Snape in Of A Sort and "Invisible"--the history of his mother, perhaps, who was a somewhat odd woman who had learned the Dark Arts as a child, or his demanding and exacting father who was staunchly on Dumbledore's side, but had all the restraint of Barty Crouch, Sr. Say I introduced the question of why a man like that was working for Dumbledore, and what it all meant and...

Well, those are all big questions, none of which had to do with the story I was telling, none of which are of interest to the characters I'm writing about, and, most important, none of which were going to be answered or even addressed in any way in the course of the story. And raising a dramatic question without the slightest intention of having it come into play is bad-faith writing--everything you write toward the beginning is an implicit promise to the reader that you're going to follow up on it, and failing to do so breaks faith.

In Characters and Viewpoint, O.S. Card talks about different "levels" of characters. You have your main characters, who are always fully characterized, and you have your supporting characters, who usually are and should be. But you also have cameos, bit parts, extras--all of these require ever smaller levels of characterization. In the case of Shifts, Remus, Sirius, Tonks, and (to some extent) Dudley are the major acting characters, so they get the whole shebang. Around them are people who have a direct impact on them: Ted and Andromeda, Peter, the OCs with whom Remus is working, Dumbledore. I did my best to give these guys reasonable lives and personalities, but not to give them really complex personal problems that would need to be resolved (okay, so I gave Ted and Andromeda a complex problem, so sue me--it was plot, though, not personal). Then there are people who don't interact with them much directly, but have an impact on the plot (Snape and Narcissa), or people who interact with them a lot but don't have that much impact on the plot (Mad-Eye, Kingsley, the Weasleys, a handful of other OCs... and, oh yeah, Harry). These are kind of background characters, and we see what Remus sees about them.

It wouldn't be appropriate to fully characterize the background folks, because they're, well... background. It's like web design--if you have an intricate, bright colored pattern, you can't read the text on top of it. You need to turn down the contrast to make it legible.

Does that make sense?

(I was amused that Snape was singled out for questioning on the characterization--he had more than people like, oh... Harry. Harry had zilch in terms of character development. Same for Hermione and Ron, and Bill Weasley, and Fleur Delacour.)

EDIT: Just to be clear, I'm not annoyed at my reviewer; it just got me started thinking about the subject.