A character's gradual transformation from good to evil, driven by choices that feel justified in the moment but lead somewhere terrible.
A corruption arc traces a character's moral decline from a place of relative goodness into villainy, cruelty, or moral bankruptcy. Unlike a sudden heel-turn, the best corruption arcs unfold through a series of small, seemingly reasonable compromises. Each decision makes sense to the character at the time, but viewed together, they form a clear path downward. The horror - and the fascination - lies in watching someone lose themselves one choice at a time.
Corruption arcs are some of the most gripping stories you can tell because they force readers to confront uncomfortable questions about their own moral flexibility. When readers catch themselves still rooting for a character who's clearly crossed a line, that's powerful storytelling. It also lets you explore how systems, trauma, and power can warp even well-intentioned people.
Michael Corleone's transformation from idealistic war hero to cold-blooded crime boss remains the gold standard for corruption arcs.
Walter White's journey from sympathetic teacher to ruthless drug kingpin is a masterclass in incremental moral compromise.
Light Yagami's arc shows how a brilliant student with good intentions becomes a serial killer who sees himself as a god.
The original corruption arc in English literature - ambition transforms a loyal warrior into a paranoid, murderous tyrant.
Build in a chain of escalating compromises. Each step should feel like a small thing at the time, even as the cumulative effect is devastating.
Even at their worst, the character should retain traces of who they used to be. Those glimpses of their former self make the corruption more tragic.
Every step down needs its own internal logic. The character should always have a justification, even if the reader can see right through it.
Write a sequence of three scenes tracking one character. In the first, they do something slightly dishonest for a genuinely good reason. In the second, they do something worse using the same justification, but the reason has gotten thinner. In the third, the justification is gone entirely - they do the harmful thing because it's become who they are.