Changers are characters who alter in significant ways as a result of the events of your story. They learn something or grow into better or worse people, but by the end of the story they are not the same personalities they were in the beginning. Their change, in its various stages, is called the story's emotional arc.

Write Great Fiction - Characters, Emotion & Viewpoint (ed. Writer's Digest Books, 2005) - ISBN: 9781582976815