In this week's post I'm going to talk about the secondary characters you might have wandering around in your work. If handled improperly, secondary and background characters will seem like part of the scenery rather than add to the flavor of your world. Why? Because it's so easy to have your secondaries just exist for the scene (or two, or whatever) they're in and then get stuffed back in the creative closet.
This is a mistake, but an understandable one. Your main characters--your protagonist(s) and your villain(s)--carry the bulk of the story, so naturally you want to focus on them. Your heroes have motivations. Hopefully your villains have motivations, too, that sound reasonable to them, rather than just having them wander around aimlessly being evil at people. But the people milling around in the background? Who cares about them?
Well, you should. You created them for a reason, and even if they're literally only there for a single scene to contribute a single piece of needed info to your hero, they need lives outside the story. This might seem like a lot of hard work that nobody's going to see, and you might be right. BUT, that guy milling around in the background might turn out to be helpful to your hero at a crucial moment.
Remember that crowd of train passengers in Spider-Man 2 that Our Intrepid Hero nearly kills himself saving from Doctor Octopus? They came to his defense when Ock tried to finish him off because they saw that Spidey was "only a kid", like any of their own offspring. They didn't have much in the way of character development, but they helped the hero. They might have been listed in the credits as Bystander on Train #1 through #9 or whatever, but they had a reason to jump to his defense.
Now, unless you're writing a sweeping high fantasy epic or whatever, it's unlikely that you're going to break out in mass quantities of background characters. However, you do need to know who your named characters are, at least, in case you need an unexpected ally (or obstacle) for your hero at a key moment in your story.
Does this mean you need to provide a complete backstory for every single character who has even a walk-on part in your novel or short story? No, obviously not. That would be a lot of record-keeping, and a project you should only undertake if you're planning on lots and lots of ground-level world-building. Even then, just focus on a small handful of people in your fictional city of ten million, or you'll be so busy making characters that you'll never get to your story.
In conclusion, while the focus of your story should be on your main cast, don't neglect that background characters. Making sure that at least you know who they are beyond the context of the story will help you make them more rounded for the reader. Mapping out what secondary characters are doing while off-screen will also help you get them in the right place at the right time for some additional support for your main characters, and who knows? Heroic Bystander #2 might become a fan favorite as a result.