Queen Mab: Of course. I expect superior, more creative treachery on your part.
Sometimes, characters form alliances. Sometimes, those alliances end in betrayal. This trope is for when both sides knew it was coming. For whatever reason, two or more characters must work together despite knowing that the alliance is temporary. This is usually the case in any Enemy Mine situation, and what distinguishes it from others is that the alliance will certainly end in an Inevitable Mutual Betrayal assuming that both parties are alive when they finish what they teamed up to do, and that they both know it from the very start. The connection may be friendly or not, and in fact both parties will frequently be horrified enough at the idea that they hope one of them dies before it comes time.
Compare Enemy Mine, which often overlaps; Betrayal Insurance, for a plan against betrayal which one or both sides may or may not have; and Rash Equilibrium, when both sides independently decide to backstab each other after agreeing to an alliance. Contrast Teeth-Clenched Teamwork, where they can't get along even for the limited time they are working together but may or may not betray each other by the end.
- In Bleach, Aizen predetermined that Ichimaru Gin would betray him when he joined up with him, nearly a hundred years ago. He was only concerned with how.
- Nearly all alliances in Liar Game. This is the reason why the protagonist is so important - with her naive and righteous attitude she can serve as The Heart for her team, because she is the only one in the game anyone can ally with reliably.
- Lupin III vs. Detective Conan: The Movie: It's a given that as soon as the heat dies down Lupin and Conan are on opposite sides of the law and will go back to acting like it, though they both talk a bigger game than their actions actually support.
- In Devil Survivor 2: The Animation, Yamato's relationship with Hibiki by the end of episode 6 and all of the surviving demon tamers except Makoto and Fumi by the end of episode 9 degenerates into this. They all need each other to defeat the Septentriones, but once that's through, nobody wants to see Yamato's ideal of a world where the strong trample the weak.
- In Astérix the Gaul, Crismus Bonus tells his second Marcus Ginantonicus that with the magic potion in their hands, they will march on Rome, overthrow Julius Caesar and form a triumvirate. As they clink their glasses to this, thought bubbles reveal their true intentions:
Crismus Bonus: I need you now, but afterwards I'll be the triumvirate on my own!
Marcus Ginantonicus: I'll have him thrown to the lions, and then I alone will be Caesar!
- Black Moon Chronicles: After going on several campaigns of Rape, Pillage, and Burn on the edges of the Empire of Lynn, Haazheel Thorn goes to the capital city of Lynn with his entourage to pledge his allegiance to the emperor as his vassal. Everyone involved knows that this is just for show and war will soon continue, but both sides are stalling for time to strengthen their forces.
- In Ultimate Video Rumble, this happens a lot due to the number of independent villain groups present. For example:
- Shao Kahn, believing that M. Bison has broken their alliance ( actually, Demitri brainwashed Bison into it), seeks the help of the heroes in tracking him down. Knowing the true situation by this point, the heroes happily point Kahn in the direction of Bison's forces, letting them take each other out as a distraction while they slip away to deal with a bigger threat.
- And in the third Rumble, fully expecting this from Bison, Geese Howard just decides to pursue other goals and lets Bison take the prize.
- In the Star Wars Expanded Universe, it is stated that Vader was planning to betray Palpatine, and that Palpatine was taking every available precaution to keep Vader under control while he searched for a viable replacement apprentice. This is par for the course with Sith apprenticeships, the master always looking for a better apprentice and the apprentice always looking for an opportunity to become the master.
- The Man from U.N.C.L.E. (2015): This is visible right as Solo and Illya start working together since both are after the same set of information which could give their respective countries an edge over everyone else, which means for obvious reasons they do not want the other to get a hold of it.
- In the Kamigawa Cycle, Toshi and Hidetsugu both knew when they formed the Hyozan that it would end in betrayal. Toshi had to make a deal to get away from Uramon and keep Hidetsugu from killing him, but Hidetsugu only expected it to be slightly more convenient. Both of them knew that one of them would betray the other, but they had hoped that one of them would die first. It is later revealed that Hidetsugu had figured out before they had even bound themselves how to kill Toshi without triggering the Hyozan magic.
- In The Hunger Games, tributes frequently form temporary alliances. Since there can only be one winner these alliances are by necessity temporary and end in betrayal, except for Katniss and Peeta.
- In Mistborn: The Original Trilogy, any alliance between the lower-class criminal gangs eventually ends in betrayal. The question is only who can profit more by turning on their onetime associates at the opportune moment. The alliance that Vin's crew forms near the beginning of the story is expected to end in betrayal, but Vin's crew decided to bail out way earlier than expected, accepting only the 3000 boxing down-payment offered by the obligators and then trying to vanish and let the other crew take the fall.
- In the Codex Alera series, everyone who works with Invidia Acquitaine tries to take her Chronic Backstabbing Disorder into account, with degrees of success that range from "filleted for their trouble" to "left Invidia stranded naked in the woods deep in enemy territory."
- In Skin Game, the plot revolves around Harry being forced into working for Nicodemus, a member of The Dresden Files' Big Bad Ensemble. Harry fully expects that Nicodemus, being Nicodemus, will turn on him the moment that their task is complete, while Nicodemus expects that Harry, being Harry, will do the same as soon as his obligation ends. The person who got Harry into this mess is also fully aware of this, and expects "superior, more creative treachery" on Harry's part.
- In The Witchlands, when Aeduen and Iseult make a deal that he'll track down Safi for her if she leads him to his stolen money, the former notes in his head that there's nothing stopping him from foregoing the money or torturing the information out of her, and there's nothing stopping her from ditching him once Safi is close enough. In the end, neither betrays the other.
- This happens pretty often on Survivor (and other reality shows with a Voted off the Island format). Players make voting blocs to knock out other players until only their alliance is left, after which they can start targeting each other. That's the point when problems can emerge, as it gets messy figuring out who will betray who first. And that's assuming that someone hasn't jumped the gun and tried to take out an ally before all the outsiders are gone.
- Season 2 of The 100 has the Grounders and the Sky People form an alliance against Mount Weather. Both sides are well aware that, once Mount Weather is dealt with, they'll probably be back to killing each other again, if they don't start doing it sooner.
- Babylon 5: After working together to advance their shared agenda, Londo and Lord Refa start to have a bit of a falling out. When Londo demands certain changes to their current policies he drives it home by announcing he's poisoned Refa's drink. Not all at once, just the first part. The second will come later, if Refa ignores his demands. When Refa asks why, Londo explains that poison was the traditional tool of the old Republic...and that sooner or later, Refa would have done the same. Londo simply declares, "I got here first."
- Eventually...Refa tries to get his vengence. Pity Londo had him Out-Gambitted.
- Endurance: Has occurred in situations regarding bigger alliances (particularly 4 team alliances). At some point, at least one member will have to be betrayed if the alliance had not split up by that point due to the rules of gameplay.
- Hawaii was an example to an extent The Purple, Red, Orange and Green Team where in an alliance. When there main rival, Yellow won the superteam selection mission, they picked Gray and Purple for their superteam while Red and Orange where paired with Brown. Whichever superteam won the following, at least alliance member would have to be sent to temple (in this case, Yellow-Purple-Gray won and Red was chosen for temple where they got eliminated.
- Another example is High Sierras where a 4 team alliance (Purple, Red, Orange and Green) made it to the final 5. Green won the temple mission and thus had to send 2 teams to temple where one of them will get eliminated. While Blue (the only non-alliance left) was an obvious choice, they had to send a team from their alliance to temple (in this case Orange, who got eliminated). Happened again in the next temple mission which Purple won and, while Blue was once again sent, they had to send Red or Green knowing whoever gets sent might not come back (Red was chosen for temple and got eliminated.)
- In the Star Trek: Voyager two-part episode "Scorpion", Voyager and the Borg team up against Species 8472. As soon as 8472 withdraws from the galaxy, the Borg try to assimilate Voyager — and get foiled by Janeway and Chakotay's counter-tactic.
- In Munchkin, most of the strategy is based around convincing people that you are the opponent who has gone the least distance across the Godzilla Threshold. Betrayals can come at any time when it would be profitable or funny, and are more or less guaranteed once you reach level 9 and will win the game if you win your next combat.
- In Diplomacy it is essential to team up with one or more of your opponents just to survive vs. other alliances. However, only one player can win, so in almost every game there will be multiple occasions where one member of an alliance will backstab the other(s) for an advantage or total victory. Ethical players will put limits on their alliance (such as it only lasting for a specific period of time) so that when they do attack their allies they won't be making a surprise attack.
- In the Game of Thrones board game, alliances can be very beneficial, but since the game ends when one nation gets 7 castles, your alliance will break the moment one member is close to getting 7. Either that player exploiting the weaker defense of his ally, or his ally stopping him from getting the 7th castle.
- Dawn of War: Winter Assault has this in all four campaigns. The Imperials are violent xenophobes, while the Eldar are known to happily allow billions of humans to die if it can save one of their own. The forces of Chaos and the orks, on the other hand, end all their conversations cheerfully reminding the other that they will kill them as soon as they're no longer needed.
- BioShock Infinite: In Part 2 of Burial at Sea, Elizabeth strikes a deal with Atlas to rescue a Little Sister; bring him the "Ace in the Hole" and he lets The Little Sister (named Sally) go. She knows that Atlas cannot be trusted and Andrew Ryan even tells her as much in an attempt to get her on his side. In the end Atlas betrays her, by threatening to lobotomize her and Sally if she didn't hand him the Ace. She does it because she knows that Atlas will die in the original Bioshock, though she dies by the end of the episode
- In Diablo III, Tyrael mentions that the Lords of Hell often lost during the Eternal Conflict because they couldn't stop betraying each other. This dependence on this trope bites the angels in the ass when Diablo becomes the Prime Evil, the sum total of all seven Great Evils in one being.
- There's a game mode in DEFCON where all the players start out as allies. Since the point of the game is to inflict as many casualties as you can on the opposing players while protecting your own cities as much as you can, this alliance will inevitably crumble.
- Kaiserreich: Legacy of the Weltkrieg: If the Second American Civil War is going badly for them, the American Union State and the Combined Syndicates of America can ally with each other against the USA. Being a far-right and far-left faction respectively, the two rebel groups naturally hate each other and will unavoidably resume hostilities after the federal government has been defeated.
- The Mortal Kombat series has the Deadly Alliance, formed by sorcerers Quan Chi and Shang Tsung. They teamed up in order to conquer Outworld, and know that if they stay together, nobody can stop them. However, they also perfectly know that after they reach their goal, the other one will betray them, and they don't intend to be on the receiving end. And as they expected, in the beginning of Mortal Kombat: Deception, after they get rid of Raiden, their alliance crumbles because they both want to be the only ruler and owner of Shinnok's Amulet.
- In El Goonish Shive, from the moment Sirleck agreed to help Magus get himself a new body, it was obvious that the former planned to betray and possess the latter. When the betrayal happens, Magus confirms he was planning for it from the start.
Magus: Not once did I ask you who you planned to possess after Ellen. Should've been a red flag. (kills Sirleck)
- In Max Steel (2013), Dredd and Makkino form an alliance to defeat Max Steel and N-Tek but both have previously admitted to the other that they don't trust each other and both fully understand that the alliance lasts only as long as Max Steel and N-Tek does.
- Avatar: The Last Airbender: After Long Feng and Azula pull off a coup in Ba Sing Sae, Long Feng approaches her with the line, "Now comes the part where I betray you." Which they both knew was coming. He then orders the Dai Li to arrest her, but she had already co-opted them, and brought them onto her side. Long Feng acknowledges that she's beaten him at his own game, which she laughs off with, "You were never even a player."
- Near the end of the first season of Transformers: Beast Wars, Megatron proposes a Maximal/Predacon truce to Optimus Primal; even admitting upfront that it's to afford him the chance to divert his attention elsewhere for a while. Primal accepts because he's honor-bound to give peace a chance - but he still sends spies to the Predacon base to find out what they're up to.
- In Teenage Mutant Ninja Turtles (2012), this trope is discussed in the second season finale. The Shredder has allied his Foot Clan with the warmongering Kraang who are preparing for an imminent invasion of New York, and must decide if he will assist in the invasion. Earlier in the season, the Shredder implies he does not trust the Kraang as he forbids Karai from dealing with them without him present. The Shredder himself is not the most honest guy in the show to begin with. Tigerclaw points out that the Kraang will eventually betray him as they care nothing for the human race. Shredder meanwhile observes that while this is true, until now, the Kraang have been pretty straightforward and have provided much for him and asking little in return. Ultimately Shredder decides to continue his alliance with the Kraang (partly due to being an insane Misanthrope Supreme), but he does not ignore the inevitability that he and the Kraang will come to blows in the future.
- This happened a lot in World War II
- The USSR and USA are an example since more or less everyone knew that conflict would be inevitable but that a Nazi victory would be far worse than a war with the other. While in 1945 there was some wargaming in the west about an invasion of Soviet-occupied eastern Europe to ensure that it would keep to its promises about free elections in Poland, this idea was dismissed out of hand by policymakers. Instead of open warfare, decades of ideological antagonism and proxy wars followed in what became known as the Cold War.
- The non-aggression pact between Germany and USSR was eventually broken by the former when they invaded the latter in 1941. Neither side was convinced that the pact with their ideological arch-enemy would last. Prior to the invasion it was also well-known that Hitler intended to attack Russia sometime in the future and, of course, he had already broken every other international agreement he had made up to that point (they mainly caught the Soviets by surprise because Stalin refused to believe that the Nazis would attack sooner than he had anticipated). More controversial is the so-called 'Soviet offensive plans theory', which posits a planned Soviet invasion of Germany concocted by Stalin around the same time.
- In a war that became part of the same war (it's complicated) the Guomindang teamed up with the warlords Yan Xishan (Shanxi province), the Guangxi Clique (Guangxi and Guangdong provinces), Long Yun (Yunnan province), Mao Zedong (Sha'anxi province) the Shandong and Guizhou Warlords, and several hundred local Warlords against Japan. After Japan surrendered, they turned on each other pretty quickly. The Guangxi Clique - Guomindang struggle was particularly fierce, with Li Zongren claiming the presidency of the Republic of China and Chiang Kai-shek fighting him (politically) for control of the army. Mao turned on everyone else too of course.