Jacob's development into a major character was a strange journey. Originally, Jacob was just a device. In Twilight, Bella needed a way to find out the truth about Edward, and the conveniently located Quileute Tribe, with all their fantastic legends, provided a cool option for that revelation. And so Jacob was born—born to tell Bella and Edward's secret.

Something happened then that I didn't expect. Jacob was my first experience with a character taking over—a minor character developing such roundness and life that I couldn't keep him locked inside a tiny role. (Since Jacob, this has reoccurred...