In fiction, a foil is a character who contrasts with another character, usually the protagonist, to highlight particular qualities of the other character. In some cases, a subplot can be used as a foil to the main plot. This is especially true in the case of metafiction and the "story within a story" motif. The word foil comes from the old practice of backing gems with foil to make them shine more brightly.
A foil usually either differs dramatically or is extremely similar but with a key difference setting them apart. The concept of a foil is also more widely applied to any comparison that is made to contrast a difference between two things. Thomas F. Gieryn places these uses of literary foils into three categories, which Tamara A. P. Metze explains as: those that emphasize the heightened contrast (this is different because ...), those that operate by exclusion (this is not X because...), and those that assign blame ("due to the slow decision-making procedures of government...").
Similarly, in Shakespeare's play Julius Caesar, the character Brutus has foils in the two characters, Cassius and Mark Antony. In the play Romeo and Juliet, Romeo and Mercutio serve as character foils for one another, as well as Macbeth and Banquo in his play Macbeth.
In William Shakespeare's tragedy Hamlet, a foil is created between Laertes and Prince Hamlet to elaborate the differences between the two men. In Act V Scene 2, Prince Hamlet tells Laertes that he will fence with him and states, "I'll be your foil, Laertes" (5.2.272). This word play reveals the foil between Hamlet and Laertes, that was developed throughout the play.
In the Harry Potter series, Draco Malfoy can be seen as a foil to the Harry Potter character; Professor Snape enables both characters "to experience the essential adventures of self-determination" but they make different choices; Harry chooses to oppose Lord Voldemort and the Death Eaters, whereas Draco eventually joins them.
George and Lennie are foils to each other in John Steinbeck's Of Mice and Men. Lennie is huge and strong as a bull but is also mentally slow, while on the other hand George is small, skinny and very smart.
Manic Pixie Dream Girl (MPDG) is a stock character type in films. Film critic Nathan Rabin, who coined the term after observing Kirsten Dunst's character in Elizabethtown (2005), said that the MPDG "exists solely in the fevered imaginations of sensitive writer-directors to teach broodingly soulful young men to embrace life and its infinite mysteries and adventures." MPDGs are said to help their men without pursuing their own happiness, and such characters never grow up; thus, their men never grow up.The Manic Pixie Dream Girl has been compared to another stock character, the Magical Negro, a black character who seems to exist only to provide spiritual or mystical help to the white savior protagonist. In both cases, the stock character has no discernible inner life, and usually only exists to provide the protagonist some important life lessons.Sidekick
A sidekick is a slang expression for a close companion or colleague (not necessarily in fiction) who is, or generally regarded as, subordinate to the one he or she accompanies.
Some well-known fictional sidekicks are Don Quixote's Sancho Panza, Sherlock Holmes' Doctor Watson, The Lone Ranger's Tonto, The Green Hornet's Kato, Shrek's Donkey (and sometimes Puss in Boots), Mickey Mouse's Donald Duck (and sometimes Goofy), Mario's Luigi, Sonic's Tails (and sometimes Knuckles), Donkey Kong's Diddy Kong, Daffy Duck's Porky Pig and Batman's Robin.Villain
A villain (also known as, "baddie", "bad guy", "evil guy", "heavy" or "black hat") is an "evil" character in a story, whether a historical narrative or, especially, a work of fiction.
Villains are usually antagonists, but this is not always the case. A female villain is occasionally called a villainess. Random House Unabridged Dictionary defines villain as "a cruelly malicious person who is involved in or devoted to wickedness or crime; scoundrel; or a character in a play, novel, or the like, who constitutes an important evil agency in the plot".