The Change Engine

A character arc is the internal transformation a character undergoes through the story's events. Walter White goes from chemistry teacher to drug lord. Michael Corleone goes from war hero to mafia boss. These arcs work because they show change happening through believable incremental steps.

The most powerful arcs involve characters making choices that reveal who they truly are under pressure. Each decision narrows their options and commits them further to a path. The audience watches someone become a version of themselves they could not have predicted at the start.