Every story centers around a conflict between a Hero and a Villain, a protagonist and an antagonist. More often than not, though, the Villain works mostly in the background, leaving the Hero to prepare for the inevitable struggle with a third character. Well, the Second, actually.
In classical theater, when drama evolved from a lone character monologue into an interaction between a pair of characters, the deuteragonist was this "second actor" (as the name implies), the literal sidekick. He would often need to swap costumes and parts depending on what the story required.
The modern "deuteragonist" (like "protagonist" and "antagonist") describes a character, not an actor, but the Second still has the next-most stage time, his history is told almost as thoroughly as the protagonist. What purpose he serves depends on the story. Just like there are numerous types of protagonists-Rocky Balboa is not Elizabeth Bennet-storytellers can employ several varieties of Seconds depending on where they want their characters to go and what they want them to say.
In romances, the protagonist and deuteragonist almost always comprise this central couple, but the rest of the time, the Second could be the Hero's ally, his competition (though not his Villian), or even an associate whose motives may both align with and vary from the Hero's at times.
In storytelling, a foil is someone that the audience will compare (probably subconsciously) to the protagonist. Draco Malfoy foils Harry Potter, for instance, emphasizing the contrast in morals between Slytherin and Gryffindor houses. When the Second serves as the foil, the comparison takes a more central role in the plot.
J. R. R. Tolkien utilized Thorin Oakenshield, his Second in "The Hobbit," as a foil. Embodying dwarven greed and pride, Thorin's quarrels with humble Bilbo Baggins help define the hobbit culture. Only after the climax does Thorin admit Bilbo's gentler approach to life is actually the more admirable.
Sometimes, the foil never changes, like Aslan from "The Lion, the Witch, and the Wardrobe," and instead highlights the protagonist's change.
Usually, the Second plays the role of a friend or ally to the Hero, and his fall adds tension and further builds the suspense until the Hero battles the Villian.
Consider Harvey Dent, the deuteragonist in "The Dark Knight." Introduced as a foil for Bruce Wayne, Dent evolves into a secondary antagonist, going from hunting the Joker to helping him. His drastic character change emphasizes the movie's theme-something Dent actually introduces in an early monologue-"You either die a Hero, or you live long enough to see yourself become the Villain."
In some stories, the Hero has enough on his plate with trying to overcome the Villain. In these cases, the Second acts not as a complication, but a catalyst. This could come from the Second's action-usually a mentorship, like between Luke Skywalker and Obi-Wan Kenobi-or merely from the inspiration he instills in the Hero.
Huck does not consider Jim to be a teacher or mentor in "The Adventures of Huckleberry Finn," but when he learns his traveling companions have betrayed the runaway slave and had him arrested, Huck must decide his own opinion on the issue: that Jim's moral character, not his skin color, is the true judge of his value.
Morpheus in "The Matrix" plays both catalyst roles for Neo. He acts initially as a mentor: pushing Neo toward his destiny as the One, teaching him the way of the Matrix, and displaying a faith that Neo struggles to gain. After Agent Smith captures him, though, Morpheus becomes Neo's passive catalyst, inspiring him to rescue his mentor at all costs.
The same could be said for Mickey from "Rocky III" who coaches Rocky, even if the champ struggles with taking the training seriously. He only really spurs Rocky to train hard enough to win after the Villian inadvertently causes his death.
When the Hero is a weaker character, his Second must act as his warrior and defender. The Terminator helps John Connor like this in "Terminator II" and "III."
"The Lord of the Rings" presents a unique Hero/Second relationship. Aragon initially leads Frodo through the dangers pursuing him in "The Fellowship of the Ring." When their paths separate for the remainder of the narrative and Aragorn becomes a secondary protagonist confronting his own destiny, bumbling Sam inherits the mantel as Frodo's Second. Sam is clearly no wingman but a sidekick, forcing Frodo to take charge himself.
Very similar to a wingman, the lovable sidekick aids the Hero in his quest, but-unlike a wingman-remains mostly behind the Hero. Many times, this type of Second acts as comic relief, such as Dory from "Finding Nemo" and Barney Rubble (not to mention Barney Fife from Andy Griffith.)
Sidekicks may act subserviently by choice or obligation, such as Genie from Disney's "Aladdin," instead of because an incompetency or lack of powers prevents them from being a wingman. Many Robin incarnations in the Batman universe fill this sidekick role despite wanting to be the wingman, a struggle that increases dramatic tension in battle and strains his relationship with Bruce the rest of the time.
This type of sidekick could also plays the straight man to the Hero's erratic character. Spock supplements Kirk's compulsive brawn with calm intellect, similar to how Dr. Watson does with Sherlock Holmes.
Crafting the Deuteragonist
In developing your own narrative's plotline, the Second should often be imagined alongside the Hero and Villain. Ask yourself:
- Who are my Hero and Villain? What is their central struggle?
- How will a third character contribute to that struggle? By helping the Hero? By betraying him? Will this Second be more capable than the Hero even? Will he only accompany the Hero because of circumstance or convenience, and if their goals clash, will the Second leave the Hero or just make things difficult?
- By giving my Second this role in the story, how does that reflect on my Hero? Is he forced to step it up, or take it back a notch? Does this increase tension with the Hero as he combats the Villain?
- How does this Second eventually become eclipsed by the bigger struggle between Hero and Villain? Will he die or swap sides, or will his loyalty to the end give the Hero the strength he needs to triumph?
By throwing the Second into the fray with the Hero and Villain, it raises the stakes in the conflict. If the Villain is rarely seen, as is typical, the Second also gives the Hero a companion at best or at worst an annoyance to keep him busy while working toward the ultimate Villain.