If you let your imagination soar during NaNoWriMo, you run the risk of a character hijacking your story. Maybe you’ve read about other writers who have had characters appear out of nowhere, fully formed, as if someone has air-dropped them into their brains. Don’t let it worry you. When a character takes over, you may find yourself with a much better story. That was my experience while writing my YA mystery A Shadow on the Snow.

My main character nineteen-year-old Rae Riley has just discovered who her father is and is getting to know her sprawling, extended family. Her thirty-seven-year-old father Mal has an eighty-year-old grandfather. A former lineman, Mal is built like a grizzly bear, and since he shares his name with his grandfather–Walter Reuel Malinowski–I wanted them to share physical characteristics too. Personally, I didn’t know any big elderly men who looked like former football players. Usually, I have to see a character as clearly as I do people in reality to feel comfortable writing about them, I had to have some person to fill the spot in my story, at least temporarily, so I picked Clint Eastwood because I knew he was a tall man and I’d seen photos of him in his eighties.

I began writing. Next thing I knew, Walter was in charge.

Every scene he was in he took center stage. As I wrote dialogue, I felt more like I was taking dictation than imagining the conversation. (Yes, we writers hear voices in our heads, but we know they’re not real. Most of the time.)

As I wrote, Walter’s appearance changed. The Clint Eastwood looks disappeared. The man I saw in my mind was as broad and intimidating as a tank with deep-set eyes and aggressively square jaw. And this change was not conscious thinking on my part. He transformed without me realizing it.

What’s more, he was fun to write. His blunt, harsh, mean personality was such a contrast to Rae and Mal. But I knew he was more than just a bully and enjoyed exploring all the facets of his character. I worked him into more scenes and the book benefited from his larger presence. But I had to remember that ,while important, Walter was still a minor character. If I didn’t keep tight control of him–something he would swear no one could do–he’d run amok and change my entire novel.

I wasn’t the only one who Walter won over. Two of my beta readers singled him out as one of their favorite characters. I’m looking forward to including him in my next mystery.

For more tips on writing characters, click here.

Who are some minor characters that you love?