Few things in writing are more thrilling than seeing the characters in your novel come alive. Instead of forging scenes with great labour out of dead material, suddenly you have real people interacting on the secret stage in your head. All you have to do is transcribe their conversations and you’ve got great dialogue. And yet — you made these beings. They are (almost) entirely in your power.

Almost, indeed. Every writer has probably created a character who has not turned out as originally envisioned. When I began writing The Friendship of Mortals, the first book of my Herbert West Trilogy, I was certain that Herbert West would be a villain rather than a hero, as he is in the original story by H.P. Lovecraft on which the book is based. He was an amoral type who used other people, both dead and alive, as experimental material. Lacking a freshly dead corpse to revivify, he made one by killing a man. How could such a person be other than a villain?

Complicating all this was my narrator, librarian Charles Milburn. To Charles, Herbert West was not uniformly black, but a multi-hued creature at once repellent and fascinating. By associating with Herbert, Charles became his friend as well as accomplice, and so presented him to the reader in an ambiguous way.

Members of my critique group have suggested that I became enamored of my version of Herbert West, sometimes making things too easy for him as a result. After some defensive huffing and puffing, I had to admit that this was so. My Herbert, like H.P. Lovecraft’s original, is slight, blond and bespectacled, but he is also well-dressed and charming — an enigmatic, possibly dangerous dude in an attractive package. I preferred to have someone like that living in my head, rather than a garden-variety grotesque geek. Coming up with a background for him that would explain his corpse-revivifying interests, and devising a more interesting end to his career than being ripped to shreds by his own monstrous creations necessitated three books.

How did this happen? How did a fictitious character who began as amoral, perhaps evil, turn out to be almost (but not quite) the opposite? I blame Charles Milburn and Loreena McKennit. Charles allowed himself to be charmed by Herbert into helping him with his dubious experiments. And while I was writing The Friendship of Mortals, I listened repeatedly to Loreena McKennit’s CD The Mask and the Mirror. I was especially taken with “The Dark Night of the Soul,” her arrangement of a poem by the mystic St. John of the Cross. Something of this song seeped into my writing and turned the course of the narrative and the natures of my principal characters.

This example illustrates the complexity of the relationship between an author and his or her fictitious characters. Reaching into yourself to create fictional people is a potentially powerful process. Those characters are in some way slices of yourself, shaped — perhaps distorted — by conscious and subconscious impulses not entirely under your control. That’s one of the things that makes writing so exciting, and perhaps a little dangerous.

And be careful with music when you’re writing! It has a potent effect on the brain, so it’s no wonder that it can get in there and mess with your imaginary creations.