Ah, secondary characters. They're like colorful, moving bits of scenery. Secondary characters can fill in the outlines of your main character, nudge the plot along, or provide some much needed comic relief. Secondary characters are your friends.
And then comes the moment when they take over your book and run amuck.
New writers may anticipate some trials with their main characters, and it's a well-founded anticipation. But the challenge of reining in secondary characters catches some people by surprise. So how should you keep your secondary characters under control?
My advice to new writers: don't even try. Let your secondary characters run wild and free. After you've gained more experience writing, you can worry about producing manicured characters. But in the early stages, forcing control over your secondary characters is tantamount to censoring yourself. Secondary characters are the vehicle your mind uses to express the creative little tweaks that your core story may need. So listen.
I have three series of books in process right now. The first series I started writing (which will be the last series published) came entirely from secondary characters. I started writing one book and was captivated by the background characters. They were so sure of themselves, and so alive. I had to know the back story of this little group. I began writing short stories about the secondary characters. The next thing I knew, I had a book – the first book in my fantasy series. And then two books. It just keeps going. Those first scenes I wrote are still around, but they've been pushed out to book five of the series. All because of secondary characters running wild and free. If I hadn't listened to them I never would have known that what looked like the beginning of something was actually the middle.
The secondary characters in the Undead Bar Association series are different. They're all vivid and unique, but each serves a specific purpose. Instead of having a single moment to shine, some of them will be recurring characters in the series. For instance, there's one character from book one, Matriculated Death, who makes an unexpected return in book two. Still just a secondary character, but his importance will grow as the series progresses.
For the steampunk trilogy, I'm taking a different approach. A dozen characters have been hand-picked to tell the story in the main book. It's a mix of major and minor / secondary characters. The fun part is getting to know each of the storytellers. You actually learn more about each individual from the way other people describe them, than from their own stories.
If a secondary character runs across your page, grabs the edge of your plot, and starts to tangle you up in your own storyline, don't stop and throw it all away. Take time to untangle things and listen to what your character is trying to say. In the end, you're really listening to your creative self.