Story structure
Character arc
The transformation or inner journey of a character over the course of a story: who they are at the end is not who they were at the start.
A character arc is "the transformation or inner journey of a character over the course of a story." The term applies most to protagonists whose beliefs or self-understanding shift under the story's pressure: Raskolnikov's confession in Crime and Punishment, Jean Valjean's redemption in Les Misérables, Michael Corleone's descent in The Godfather, Walter White's fall in Breaking Bad.
Craft teaching sorts arcs into three shapes: the positive change arc (a false belief cracks and the character embraces a truth), the negative arc (the character ends worse, even amid victory) and the flat arc (a steadfast character changes the world instead). Whatever the shape, the arc is why the plot matters: events land on a person and leave a mark. The full treatment is the character arcs guide; the want versus need pair is its engine.