A foil character is a character whose contrast with another, usually the protagonist, makes that character's traits easier to see. The best foils share a situation, goal or background with the main character and respond to it differently, so the difference reads as choice.
The word comes from jewelry. A foil was a thin leaf of metal set under a stone in a closed setting to make it look brighter, and by the 1580s English also used the word for a person who sets off another by contrast. Shakespeare leaned on the image. In Henry IV, Part 1, Prince Hal plans to reform late, so his good conduct will gleam "like bright metal on a sullen ground" and draw more eyes "than that which hath no foil to set it off."
Foil is a relationship, not a role. A best friend can be one, and so can a rival, a villain, a sibling or a stranger who shows up for a single chapter. A character can be a foil to several others at once, and the protagonist can be the foil to someone else.
Foil character examples
For, by the image of my cause, I see
The portraiture of his.
Hamlet kills Polonius, and Laertes comes home to a murdered father, just as Hamlet did. He doesn't brood. He storms the palace with a mob behind him, and when Claudius asks how far he would go, he says he would cut Hamlet's throat in a church. In Act 3 Hamlet found Claudius at prayer and put his sword away. Fortinbras, whose father old Hamlet killed, makes a third son with the same debt. As they choose weapons for the duel, Hamlet tells Laertes, "I'll be your foil," punning on both senses: the blunted fencing sword and the dark backing that makes a jewel shine.
The instruments of darkness tell us truths,
Win us with honest trifles, to betray's
In deepest consequence.
The witches greet both generals on the same heath. Macbeth will be king. Banquo will father kings, "though thou be none." Macbeth turns the prophecy into a plan. Banquo hears the same words and treats them as bait. He is tempted too, and later hopes the prophecy holds for his sons, but he does nothing to bring it about. Because both men got the same temptation in the same minute, Macbeth's choice can't be blamed on circumstance.
I ask only a comfortable home.
Mr. Collins proposes to Elizabeth Bennet, and she turns him down. Within days her friend Charlotte Lucas accepts him, and tells Elizabeth she has never been romantic. Austen doesn't make Charlotte a fool. She has little money and few prospects, and her reasons are sound. That is what makes her useful: her choice shows the price of Elizabeth's refusal. Elizabeth has no fortune either, and Collins is the man who will inherit her family's house.
Meanwhile Clerval occupied himself, so to speak, with the moral relations of things.
Victor wants "the secrets of heaven and earth." His friend Henry Clerval reads about heroes and hopes to do good among people. Years later, wrecked by what he has made, Victor travels with Clerval and sees in him "the image of my former self." Clerval's warmth measures what Victor's obsession has cost. Then the creature kills Clerval, and the cost lands on the foil.
It may be that you are not yourself luminous, but you are a conductor of light.
Watson examines a walking stick a visitor has left behind and decides it belonged to a country doctor and was a gift from a local hunt. Holmes praises him, then explains that most of it was wrong and that the mistakes helped: the initials on the stick stand for Charing Cross Hospital. Watson's guesses are sensible, the kind a reader would make, so the distance between him and Holmes is the distance between us and Holmes. A sidekick foil only works if he isn't a fool.
Harry and Draco Malfoy start Hogwarts in the same year, and both arrive with a name people know. On the train, Draco warns Harry that some wizarding families are better than others and holds out his hand. Harry doesn't take it. At the Sorting, the Hat considers Slytherin for Harry, and Harry asks it not to. Draco is sent there almost before the Hat touches his head. The second book adds a closer foil in Tom Riddle, another half-blood orphan who can talk to snakes. When Harry worries about how much they share, Dumbledore tells him that choices show who a person is far more than abilities do.
The device works on whole storylines too. In King Lear, Gloucester trusts the wrong son while Lear trusts the wrong daughters, and the subplot turns the king's mistake into a pattern. Other pairs worth studying: Romeo and the mocking Mercutio, Heathcliff and Edgar Linton in Wuthering Heights, and George and Lennie in Of Mice and Men.
How to write a foil in your manuscript
Start with the trait you want readers to see in your protagonist: caution, pride, loyalty, a talent for lying. A foil makes one trait visible. Pick the trait first, then build the person.
- Share more than you change. Same age, same job, same family, same temptation. Then change the choice. Hamlet and Laertes share a dead father. Elizabeth and Charlotte share a suitor. Two people who differ in everything are just two different people.
- Test them in the same scene. Contrast shows under identical pressure: the same offer, the same bad news, the same question. Banquo's caution lands because he heard exactly what Macbeth heard.
- Give the foil a want of their own. A character who exists only to be the opposite reads as a prop. Charlotte wants a home. Laertes wants revenge as badly as Hamlet does.
- Don't rig the comparison. If the foil is wrong about everything, the contrast flatters your protagonist and readers notice. Readers still argue that Charlotte chose well.
- Contrast choices, not looks. Tall and short, neat and messy: physical contrast helps readers tell two people apart, but it reveals nothing about either of them.
Keep the narrator out of it, too. A line like "unlike her sister, she never took risks" does the reader's work for them. This is show, don't tell applied to a pair of characters.
Told: Ines had always been careful. Her old classmate Theo was her opposite: loud, reckless and sure of himself. That was why his first restaurant had failed and why hers didn't exist yet.
Shown: The landlord laid two copies of the lease on the bar. Theo read the first page, asked whether the hood vents worked, and signed it under his pint glass. Ines took hers home. By midnight she had priced the walk-in repair, the liquor license and nine months of rent with an empty dining room. In the morning she put the lease in the kitchen drawer, on top of the two from last year.
Same offer, same bar, same night. The second version never says "opposite," and the reader learns more about Ines from what Theo does. Theo isn't a fool either. His first place failed, but by morning he is the one with a lease. Leave readers unsure which of them is right.
A foil can also go wrong by outshining the lead. If your beta readers like the friend more than the hero, the protagonist usually wants too little. Once a draft exists, ask a reader to describe your protagonist and the foil in three words each. If the words don't pull against each other on the trait you chose, the contrast isn't landing. In Strokes you can put the same question to the AI Assistant with the chapters added to the chat as context.
Foil vs. antagonist, sidekick and double
| Term | Defined by | Example |
|---|---|---|
| TermFoil | Defined byContrast: what one character's choices reveal about another | ExampleLaertes to Hamlet |
| TermAntagonist | Defined byOpposition: who or what stands in the protagonist's way | ExampleClaudius to Hamlet |
| TermSidekick | Defined byLoyalty: who travels with the hero and helps | ExampleWatson to Holmes |
| TermDouble | Defined byLikeness: a second self, often the hidden half | ExampleThe second William Wilson in Poe's "William Wilson" (1839) |
| TermStraight man | Defined byComedy: the calm partner whose reactions set up the jokes | ExampleBud Abbott to Lou Costello |
The test is what the character does for the story. An antagonist blocks the goal. A foil clarifies the person. Claudius blocks Hamlet at every turn but shares nothing of his situation, so he makes a weak foil. Laertes hardly gets in Hamlet's way until the final act, and he is the play's clearest foil. When one character does both jobs, as Moriarty does for Holmes, you get the strongest version: the same gifts put to the opposite use. The guide How to write a villain readers believe in builds an antagonist that way.
A foil is juxtaposition applied to people, and it does its best work on a character who changes. To plan what your protagonist wants and how they change, read How to develop characters: want, need, wound and arc, then give the foil a page of its own in the character profile template.
