Who is the protagonist in Characters and Viewpoint by Orson Scott Card?

The protagonist is one of the main types of character as defined by the author. Other terms commonly substituted for "protagonist" include "hero", or "central character." The protagonist is defined by a variety of attributes—s/he is the character who undergoes the most significant personal transformation over the course of a narrative, and/or who plays the most active role in motivating/defining the action, and/or who simply has the most to do, who takes up the most page space.