Games with multiple protagonist characters usually have them on the same side. Some games, however, spice things up by having them fight each other.

In video games, the player usually controls a character who fights against an enemy force. Even in games with multiple protagonists, they're typically on the same side as one another, with the player controlling both at the same time or separately, working towards related goals.

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Some games, however, throw a spanner in the works by having multiple player characters come into conflict with one another. Whether they fight because of a misunderstanding, their alliance breaking down, or the two being revealed to be enemies from the start, the characters come to blows at some point in the story, typically with the player controlling one of them.

There are actually three player characters in NieR: Automata: 2B, 9S, and A2. Of these, 2B and 9S are the only playable characters in the first two playthroughs, with A2 appearing as an infrequent antagonist. Things take a more tragic turn in the game's third playthrough, however, when the player alternates between 9S and A2.

The two inevitably meet at the top of the Machines' Tower, and a fight cannot be avoided. 9S thinks that A2 murdered 2B, rather than mercy-killing her at her request, and has succumbed to the Logic Plague, forcing A2 to defend herself. The player chooses which to control, but they both die in the aftermath of the fight either way.

The central story arc in the Star Wars prequels is that of Anakin Skywalker turning to the Dark Side and becoming Darth Vader, which sees his ally and mentor, Obi-Wan Kenobi, forced to take up arms to stop him. Their battle on the planet Mustafar is the climactic bout of the trilogy, pitting them against each other.

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This is recreated surprisingly accurately in Lego Star Wars: The Video Game and again in The Skywalker Saga. Despite the entire game being a cooperative experience between the two characters, the final mission pits the two against each other, with the player controlling either Obi-Wan or Anakin. In two-player mode, it becomes a competitive match, with each player trying to kill the other.

The Fire Emblem series has experimented with player characters fighting each other before in Radiant Dawn, with the game's third chapter having the player control units on each side of the Laguz-Begnion War in alternating chapters. Three Houses takes the concept further, playing it to its logical end.

In the game's first part, the titular three houses are all factions of students at the Officer's Academy, and the only violence between them is mock battles. In the game's second part, however, the player is forced to lead their chosen playable faction against the other two as war breaks out, resulting in the permanent deaths of any of the enemy faction units killed in the conflict.

A Way Out is a game that is only playable with two players, each controlling one of two protagonists Vincent and Leo as they work together to escape prison and take their revenge on the crime lord Harvey. Once their work is done, Vincent reveals himself to be an undercover cop, enraging Leo and causing violence to break out between the two.

After working together and building the characters' relationships for the whole game, the final playable section is a series of player-versus-player fights. Leo and Harvey first engage in a vehicle chase, before they're forced into a close-range gunfight. One of them has to die, with the ending changing depending on which survives.

The first playable protagonist in Kingdom Hearts II is Roxas, a boy living in Twilight Town who fights off Organization XIII in the game's opening hours. Afterwards, control switches to series mainstay Sora, who the player controls for the rest of the game as the plot continues on from the original Kingdom Hearts.

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Over the course of the game, Roxas is revealed to be Sora's Nobody. The two fight in the World That Never Was in a clash that Sora ultimately wins. In the original version of the game, the fight is nothing more than a cutscene, but Kingdom Hearts II Final Mix adds a playable version of the boss battle.

Arc the Lad: Twilight of the Spirits is a 2003 RPG for the PlayStation 2 that sees the story alternate between two player characters, Kharg and Darc - who are actually hybrid brothers. The two have their own companions, quests, and storylines, but inevitably clash in the game's final chapter.

The player can choose which brother's party they want to control during the fight, although it makes no difference to the plot. Whichever side wins, the game's main antagonist takes advantage of their clash to further his plans, and the rest of the final chapter sees the player control the game's entire cast as they join forces to fight him.

The plot of Heavy Rain has the player take control of four individuals investigating the Origami Killer. A twist in the late game reveals Scott Shelby, one of these four player characters, to actually be the Origami Killer. As a result, he takes on the role of final antagonist once the other cast members track down his location.

There is no option to control Scott during the fight, with the player instead controlling Ethan Mars, Norman Jayden, or Madison Paige depending on their choices. Although Scott is unplayable during the fight, he can still win if the player's performance is poor enough, leading to a slate of the game's worst endings.

Fighting games often see members of their playable cast battling each other over the course of their storyline. Few build up to it as much as Injustice 2, however, when Brainiac's attack on Earth forces Batman and the Insurgency to release Superman from prison to fight alongside them.

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Despite hints of a desire for both sides to reconcile, they come to blows following Brainiac's defeat, unable to decide how to deal with their fallen foe. Their respective allies begin to fight amongst themselves, and after controlling both in the game's final act, the player has to choose who they wish to side with between Batman and Superman.

The first The Last of Us game features two playable characters, Joel Miller and Ellie Williams, but they are a closely-allied pair who never come to blows. Its sequel, The Last of Us Part II, takes a wholly different approach. The game's plot follows the conflict between Ellie and new character Abby Anderson after the latter kills Joel to avenge her father.

After Ellie tracks Abby down, control suddenly switches, and the player experiences the conflict from Abby's point of view. Events build back up to the same fight from Abby's perspective, resulting in her choosing to spare Ellie's life. The fight isn't done, however, as the final sequence sees Ellie go after Abby once more. This time, the player controls Ellie in the fight, and, once again, both of them come of out it alive.

Grand Theft Auto V has three protagonists - un-retired criminal Michael Townley, gangster Franklin Clinton, and violent robber Trevor Phillips. The three wind up working together in a crime spree, manipulated by outside forces, bonding in complex ways, and becoming more than just allies.

In the game's climax, Franklin is approached by two different parties, one wants Michael dead and the other sees Trevor as a liability. The player can choose to have Franklin refuse to kill either and go through a much harder final fight, but two of the game's endings see Franklin betray a friend, making the final fight one against a fellow player character.

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Isaac Williams is a movie-goer, TV watcher, journalist, blogger, gamer, comic book-fan, and roleplayer. He's been a bartender and a waiter, and now he writes lists for CBR. He focuses on TV shows and movies. In his free time, Isaac can be found gaming, reading, playing D&D, walking Birmingham's lengthy canals, and catching up on movies.