In my novel The Wan, a science fiction novel set on a distant planet in a far future, with a human colony struggling against genetics, climate and aliens, I have three protagonists/antagonists. Firdaus the fallen ruler was my original protagonist, but his nemesis Ing, former human, former scientist, came onto the stage very early on, in fact in the first scene I envisaged for the book. Ing stands over Firdaus who lies defeated in the mud and taunts him.
So far so good! Good guy, bad girl, enough for a novel, right? But then I decided I needed a human prop so Ing could show Firdaus what happens if a human being is turned into a Wan. I made them buy a slave girl from a poor village, so Ing could kill her.
But the damn slave girl didn’t want to stay dead. In the one brief chapter I had originally allotted to her, she came to life so vividly that I just couldn´t make myself kill her. And Frog turned out to be absolutely vital to the story, in fact turning out to be the protagonist who changes the most.
If I hadn’t listened to my subconscious the book would look very different than its present form, and may not even have been finished let alone sold.
The message I´ve taken from this is not to plot out too tightly. Leave room for the unexpected, in other words your powerful subconscious, with its processing power many times that of your conscious mind, a soup of the dark and the crazy that will throw up gobbets that will season your story!