I've always answered that Jessica was actually modeled on a friend of mine (named Jessica) who was an Aubrey fan and asked me to "set Aubrey up" with a character named Jessica. That's true, but until recently another inspiration had completely slipped my mind.
A reader asked me if I had ever considered using a pen name. I had, but when I published my first book, my agent and publisher convinced me to use my real name. They said it was more "writerly." I feel like there were other arguments made for each side, but I wasn't wedded to the pen name so I went with it. The reader-question reminded me of an odd and somewhat creepy coincidence that occurred shortly after I finished the first draft of In the Forests of the Night.
As I've mentioned many times in many places, Forests wasn't the first novel I ever finished; I believe it was the seventh. The first novel was titled Red Moon and featured a protagonist named Nancy Collins. It didn't have much plot and the characters were all directly inspired by my friends, but it introduced me to the Nyeusigrube vampires.
I kept developing the world and practicing the craft of writing until I finally produced Forests in 1997. For those of you who haven't read it, black roses have a special significance in Nyeusigrube. Aubrey gives one to Risika in Forests, and they appear in other ways in other books. So imagine my surprise when my friend Jessica comes in, shortly after reading the first draft of In the Forests of the Night, with this book:
A Dozen Black Roses by
Nancy A Collins
Can you see how this started my mind pondering what would happen if my characters really were out there? I don't think Nancy from Red Moon would have made a very good novelist, but the possibilities intrigued me, so I started writing. When I got stuck and debated scrapping the story, Jessica demanded I set her up with Aubrey, and that was just the wrinkle I needed to finish Demon- and the rest is, as they say, history.