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.
Nancy KressCharacterization is not divorced from plot, not a coat of paint you slap on after the structure of events is already built. Rather characterization is inseparable from plot.
Nancy Kress