Terminator Twosome

"The computer which controlled the machines, Skynet, sent two Terminators back through time. Their mission: to destroy the leader of the human Resistance, John Connor, my son. The first Terminator was programmed to strike at me, in the year 1984, before John was born. It failed. The second was sent to strike at John himself, when he was still a child. As before, the Resistance was able to send a lone warrior, a protector for John. It was just a question of which one of them would reach him first."

— Sarah Connor, Terminator 2: Judgment Day (Opening Narration)

Two warriors are sent back in time. One to change history, one to ensure it takes its established course. Or, at least, to prevent the first one from changing things. A game of cat and mouse ensues.

Can also be thought of as Evil Counterpart IN TIME! If it does not overlap with Set Right What Once Went Wrong, it will instead overlap with Make Wrong What Once Went Right: In this case, the historical event in question goes as it originally did in the "good" timeline, and is averted in the "bad" timeline.

Occasionally also occurs with dimensional travel with both the protagonist and the antagonist Trapped in Another World.

Named, of course, for the Terminator movies, wherein a robotic superassassin that looks like a real human is sent back in time to pre-emptively kill the future leader of the human resistance in a Robot War. Paradox schmaradox! Compare Scry vs. Scry, where it's oracles doing this with clairvoyance. For characters who are Expies of Arnold's iconic character from Terminator, see Terminator Impersonator.

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Examples:

Anime & Manga

• Dragon Ball Z: Cell and Future Trunks, although they come from different timelines, and weren't inspired by the other's actions. Trunks came back in order to save Goku from dying, while Cell came back because his timeline's Trunks had killed the Androids (who Cell needed to achieve his Perfect form) prior to attempting the trip. Oddly enough, because of this they've each killed two versions of the other: Trunks kills the embryonic Present Cell and the Imperfect Cell of his timeline, while Cell kills the Trunks of his timeline and Future Trunks (temporarily).
• Fairy Tail: The climax of the Grand Magic Games has Future Lucy and Future Rogue, though they both come from different timelines. Future Lucy came back to stop Princess Hisui from using the Eclipse Gate to kill Zeref before he became immortal, which would result in an army of 10,000 dragons coming through, devastating the world and killing everyone. Future Rogue, however, comes from a future where Future Lucy succeeded, yet Acnologia took over the world and killed everyone instead, so he uses the Eclipse to come back before Future Lucy does to ensure the gates open by pulling Hisui's strings and killing Present Lucy to prevent her from getting in the way, thereby giving him an army of dragons with which to kill Acnologia and take over the world.^note Funnily enough, Future Rogue is just as surprised at the existence of Future Lucy as she is seeing another time traveler, as he never learned it was her specifically in his timeline that influenced the gate closing. In the end, Future Lucy takes the death blow for her present self, who is able to piece the truth together from the lies fast enough to shut the gate to let only seven dragons through, which eventually leads to the Eclipse being destroyed so the time travelers wouldn't be able to use it in the first place.
• HuGtto! Pretty Cure has the heroic time travelers, Hugtan and Hariham Harry, travel back to the past to prevent the Bad Future they came from which causes them to cross the path of the main heroine Hana Nono. Meanwhile, the evil corporation, Criasu Corp, also travels to the past to try and kill Karry and recapture Hugtan so they can use her powers to enforce the bad future's existence, believing that the only fate humanity is capable of reaching is death and despair.
• Negima! Magister Negi Magi has a complex version of this: A Well-Intentioned Extremist from the future goes back to Set Right What Once Went Wrong, bringing her to the storyline's present. Unfortunately, her goals would cause major trouble for the main characters (turning into an ermine can put a crimp in anyone's plans), and she sends them a week forward in time to a future in which she's already won. Good thing Negi can go back in time too...

Audio Plays

• The Big Finish Doctor Who episode "Flip-Flop" has two storylines, each taking place before the other — with the same characters from each reality crossing over into the other one at the halfway point after going back in time, then going back in time to try and undo what they've done, causing the events in the other reality in the process.

Comic Books

• Marvel Universe:
  • Cable came back in time to prevent the future he grew up in. Stryfe, his evil clone, then came back in time to stop him — not so much because he was hugely enamoured of their home era, but rather because he lived to screw with Cable's life. Oh, and then Cable's evil adopted son came back as well... Later X-Men storylines have Cable jumping into the future to protect Hope Summers, a girl he believes will become the saviour, while Bishop wants to kill her because in his original timeline, she becomes The Antichrist.
  • Slightly less directly, Bishop originally came back in time hunting a group of time-traveling criminals, but then decided to use his new location to protect the X-Men and prevent his home timeline. The criminals he was hunting don't seem overly concerned with this.
  • Then there's the Legionquest story, which culminates in Professor X's evil son (yes, this is something of a recurring theme for the X-Men) traveling back to the 1950s in order to kill Magneto before he becomes powerful. An entire team of X-Men go after him. Between them, they screw things up even worse.
  • Iron Man and Doctor Doom for some reason do this often. They wind up in Camelot once in Doomquest, and another time they invert the trope by traveling to the future (after Merlin has awakened and King Arthur has reincarnated). Often, though they end up taking a third option and working together to get back. They do it again in Mighty Avengers. It helps that both Doom and Stark have nothing to gain from changing anything in the specific past periods they enter, and both would rather keep the present they have, seeing as it's dangerous to fuck with reality and all that.
  • In Age of Ultron, Wolverine goes back in time to kill Hank Pym in order to stop the titular robot, while Sue Storm goes back in time to stop him. He does kill him, but discovers the alternative is far worse.
  • Hilariously, after enough of these stories and Bad Future stories have come and gone, Marvel officially threw their hands up and rendered all of them ultimately pointless by establishing that time travel never actually changes anything in the time traveler's original timeline, instead creating a whole new alternate timeline running parallel to the original.
• The New 52: Futures End is about Terry McGinnis going back in time to prevent Brother Eye from taking over the world. Naturally, he's followed (some 12 issues later) by a cyborg who's Bruce Wayne and the Joker stitched together.
• RoboCop Versus The Terminator has a human sent back to kill the former Alex Murphy before he can grant Skynet sentience, and a Terminator sent back to protect RoboCop by any means necessary — whether he wants it or not.

Fan Works

• Down the Karmic Hole has one between Bunnyx, who's gone back to the past of the The Karma of Lies timeline to ensure the events don't happen as they did, and the mysterious time traveling Butterfly user, who instead intends for the timeline to stay exactly as it is.
• The Harry Potter fanfic Fusion of Destinies features a spell that can pull a deadly weapon from the future, but in a form of Equivalent Exchange, also brings a person with the knowledge or ability to defeat it. A long time ago, a Goblin rebellion used the spell and got a nuclear bomb along with a technician who gave his life to disarm it. When Voldemort casts it, it brings back the X Parasite and Samus Aran.
• In Hogyoku ex Machina, Ichigo and Aizen are both sent back in time Peggy Sue-style after a Mutual Kill; Aizen aims to put his Evil Plan into action again, while Ichigo tries to stop it.
• A variation shows up in the Pony POV Series Dark World Series in that the twosome are from two different potential futures. The Nameless Passenger is revealed to be Twilight's potential Nightmare self Nightmare Eclipse trying to make Twilight become her and continue her "Groundhog Day" Loop plan while the Benevolent Interloper is her potential Alicorn self Princess Amicitia who's trying to help Twilight defeat Eclipse, becoming her instead. Amicitia wins and Twilight then performs her actions to close the Stable Time Loop and locking Eclipse's defeat in stone.
• Queen of All Oni has an interesting, all-evil version of this pop up in one chapter — Drago comes back in time to kill Queen Jade for no other reason than to secure his own chance at ruling the world in the future. Karasu, meanwhile, is sent back by the Matriarch (Jade's future self) in order to preserve the timeline. Ultimately, Drago is banished back to the future and imprisoned by the Matriarch, while Karasu is trapped in the past and imprisoned by Section 13.
• Played both ways in Ship War AU, wherein Elizabeth Butterfly and Jam Diaz, half-siblings with the same father from two alternate futures are sent to the present, and are trying to ensure their own existence by playing matchmaker for their parents. Subverted later on, as Jam comes from a Bad Future, and is willing to sacrifice his own existence and let Elizabeth's parents get together as long as the apocalyptic event that ruined his world doesn't happen.
• During one Omake in White Devil of the Moon, Chibi-Usa attempts to prevent Nanoha and Fate from meeting, with Vivio trying to stop her.

Films — Animation

• Exaggerated in Batman Ninja, with several villains fighting for control of feudal Japan, and Batman and his sidekicks wanting to bring them back to the present and restore the timeline.
• My Little Pony: Equestria Girls uses the interdimensional travel variety: Sunset Shimmer wants to retrieve the MacGuffin from the human high school so that she can, you guessed it, Take Over the World. Twilight Sparkle is trying to bring the MacGuffin back to Equestria.

Films — Live-Action

• At the end of 2009: Lost Memories, Saigo and Sakamoto end up in the past struggling to avoid or ensure the assassination of Ito Hirobumi.
• In one of the Austin Powers movies, when Doctor Evil returns, Austin Powers himself is unfrozen to deal with him. The first sequel plays it straight, with Austin following Evil into the past.
• Back to the Future Part II: A Terminator Threesome happens when Marty and Doc travel back to 1955 to undo Old Biff's tampering with the timeline. To make this more confusing, it's set at the same time as the first movie, so Marty and Doc have to avoid that film's younger Marty who's unaware of other time travellers in order not to mess the timeline up further.
• Bill & Ted:
  • In Bill & Ted's Bogus Journey, Rufus follows the robot duplicates of Bill and Ted into the past to try and stop them killing the originals.
  • In Bill & Ted Face the Music, the Great Leader sends another robot to assassinate Bill and Ted while she and Rufus' daughter Kelly go back to try and save them.
• Captain America (1990) with Captain America and the Red Skull being revived in the future.
• Demolition Man inverts the trope, sending two people from the present into the future. One is a psychotic criminal "mistakenly" unfrozen from cryogenic sleep, the other is a present-day cop also in cryogenic sleep for a crime he was framed for by said psychotic criminal, unfrozen to deal with someone simply too evil and dangerous for the wimpified future cops to handle.
• Cassie and Millie in Frequently Asked Questions About Time Travel. The former travels back in time to repair time leaks while the latter is a time terrorist (they call themselves "editors") who comes to kill our heroes.
• The Post-Credits Scene from Idiocracy reveals that Rita's pimp Upgrayedd has also been frozen for 500 years, implying this scenario.
• A non-time travel example in Legion with the Archangels Michael and Gabriel. It follows the same notes because the two of them know the future thanks to their supernatural powers. They are seeking, respectively, to allow or prevent the birth of The Chosen One who will save humanity after God starts the Apocalypse.
• Early scripts and the Comic-Book Adaptation for Masters of the Universe reveal that Eternia was an Earth colony in the future meaning that He-Man's gang and Skeletor's mooks were traveling back in time when they came to Earth.
• Men in Black 3: Boris the Animal goes back in time to 1969 to kill Agent K. Agent J goes back to stop him. J deliberately arrives a day earlier than Boris in order to give himself time to stop Boris.
• This is technically the explanation for the Gainax Ending to Planet of the Apes (2001) where Leo gets back to his own time and finds Earth ruled by apes. DVD features explain that General Thade found the other space pod and used it to travel further back and conquer Earth.
• The Santa Clause 3: The Escape Clause has Scott/Santa and Jack Frost travelling back to the first movie to fight over the previous Santa's coat to see who gets to be the new Santa. It creates a Bad Future where Jack Frost/Santa has monetized Christmas. The second time they go back, Scott manages to hold Jack back, letting his past self get the coat like he did originally.
• The Smurfs has a group of Smurfs transported to modern day New York alongside their nemesis, Gargamel and his cat.
• A non-Time Travel example in The Sorcerer's Apprentice. Dave's first encounter with Balthazar and Horvath in 2000 results in both wizards being trapped in an ancient Chinese urn for 10 years (to the day). Oh, and both are fully awake all this time. In 2010, Horvath ends up coming out of the urn about a minute before Balthazar and throws the urn from a window in an attempt to stop Balthazar.
• Star Trek:
  • Star Trek: First Contact mixes up this trope by having the twosome be ships. A Borg Sphere and the Enterprise-E travel from the 24th century to a post-World War III mid-21st century Earth. The former to prevent mankind's first contact with the Vulcan race (which will result in the Federation being formed that would stop the Borg repeatedly from conquering the Alpha Quadrant) and the latter to ensure that first contact proceeds as it's meant to.
  • A variant in Star Trek (2009); Nero and Spock are both accidentally sent back in time due to an Unrealistic Black Hole. Nero takes advantage of this by using futuristic mining technology to destroy Federation planets while Spock recruits past Kirk to stop him. In this case, the whole event creates a separate branched timeline which does not affect the original, so they're not trying to protect the future, but the plot still follows much the same formula.
• Terminator, obviously. Basically, the entire franchise is a conflict between Skynet and the adult John Connor repeatedly sending their agents back in time to subvert each other.
  • In The Terminator, a robot is sent back to kill Sarah Connor before she even gives birth to John Connor, and a Badass Normal human is sent back to protect her.
  • In Terminator 2: Judgment Day, a shapeshifting robot is sent back to kill John Connor as a child. A reprogrammed robot like the evil one in the first movie is sent back to protect him.
  • In Terminator 3: Rise of the Machines, because John Connor cannot be located, the T-X is instead sent after who will become John Connor's top lieutenants and wife. Finding John Connor was just a bonus.
  • In Terminator Genisys, things get thrown out of whack. First two terminators are sent after Sarah Connor as a child, one to protect and the other to kill her. Then, the T-800 is sent as planned by Skynet to kill Sarah Connor ala the first movie, with Kyle Reese sent back to stop it, and the T-1000 sent back to stop him, who is in turn foiled by Sarah Connor and the first T-800 sent back to protect her. After which the three go forward in time to Skynet's creation to destroy it before it can cause judgement day in the first place, with the T-3000 in turn sent to protect Skynet. Confused yet?
  • If that wasn't confusing enough, Terminator: Dark Fate disregards all movies after the second as Alternate Timeline and takes its place as the new third movie, where a new liquid metal Terminator is sent to terminate the new leader of the Resistance, with a cyborg member of the Resistance sent back to protect her, aided in the present by Sarah Connor and the reformed T-800 who successfully killed John Connor.
• Time After Time has H. G. Wells traveling into the future in pursuit of Jack the Ripper.
• Timecop features Jean-Claude Van Damme as, well, a Timecop who travels to the past to apprehend criminals who threaten to change the timeline.
• Trancers: When an evil psychic goes back in time to present day Los Angeles, Jack Deth is sent back to stop him.
• A variant in Warlock (1989); the Warlock escapes to the future and the witch hunter Redferne follows to hunt him down.

Literature

• Used with a ridiculously complex plot in Animorphs: Megamorphs 3: Elfangor's Secret. In brief, a human (John Berryman) who is mind-controlled by an Alien Invader (Visser 4) gets a time machine, and the heroes (4 human teenagers, a human-brained hawk, and an alien, each of whom can change into animals) follow him through time. As part of some elaborate treaty involving god-like beings, the heroes become immortal after Jake is shot with a musket while Washington is crossing the Delaware. Washington dies as well, thanks to Berryman/Visser 4 tipping off the British. Because of Visser 4's influence on time, the course of history is changed, to the point that in World War II, Nazis are the good guys and the British still hold slaves. The heroes were not aware of this while at Normandy, and neither was Visser 4. The protagonists' fighting for the British at Normandy brings a British victory, dooming the world to slavery. After much debate about the ethics of changing the course of time once more, the heroes decide to go back in time and prevent John Berryman's birth, stopping the entire sorry situation in the first place and saving Jake.
• In The Apocalypse Troll, an alien-created cyborg-modified human is sent back in time to destroy humanity before they develop FTL space travel. A human space-naval officer also goes back in time to stop it. Unusually for the trope, it started as two entire Standard Sci-Fi Fleet battle groups fighting both before and after the actual time travel, but each side only had a single survivor left after all the nukes finished flying, so this trope still applies.
• In the Belisarius Series, two artificial intelligences from opposite sides of a far-future war get sent back to the early Middle Ages, one to try and alter the timeline so the evil side wins the future war, the other to try and stop the first one, via recruiting local Badass Normal allies. A semi-subversion, since both sides are attempting to change the timeline. Indeed, both rely on massively altering the cultural and technological evolution of the world; they just each want history to evolve in a different direction. This is because, after the changes already made by the "bad" AI, the timeline has already been irrevocably changed, so the "good" AI needs to ensure that the right culture comes out on top.
• In Dies Irae, Heljanita wants to change the past, and Darkscar wants to unchange it.
• The Draka: In Drakon, a genetically engineered superhuman woman accidentally travels through a wormhole from an alternate future back to a world resembling our own present time, and promptly begins trying to find a way to re-open the wormhole and bring through a conquering army of more genetic supermen. A lone Cyborg human is also sent back through a similar wormhole to stop her.
• For King and Country, by Robert Asprin and Linda Evans, features what seems to be an example of an IRA agent traveling back to Arthurian times to change history in Ireland's favor or simply punish England, and a British soldier trying to stop it. They go all the way back to around 500 AD or so and share the bodies of people close to King Arthur. It seems like a Stable Time Loop and/or Tricked Out Time, but the ending is a little ambiguous. Meanwhile, in the Future…, their bodies remain in a comatose state while they are in the past.
• In The Last Day of Creation by Wolfgang Jeschke, the US government invents time travel and sends an expedition millions of years into the past to steal oil from Saudi Arabia, pipe it across the Mediterranean (then a dry lakebed) and ship it to what will become the United States. Only on arrival they find themselves attacked by a better armed and organised force sent by the Arab states (yes, this novel was the inspiration for Original War). As there's been a temporal arms race triggered by all this, the future changes so much that both sides are stranded in the past as the governments that sent them no longer exist and therefore won't develop the technology to bring them back.
• Night Watch (Discworld) features Sam Vimes and a criminal both accidentally going back in time, and Sam Vimes has to stop him from changing history for the worse — while wondering whether he can morally allow history to run its course when it means innocent people dying that could be saved if he used his knowledge from the future to make a few changes of his own. He finally decides to make the changes, though these turn out to be entirely necessary to counteract those of his nemesis and arrive at broadly the same present they left.
• In Rebel in Time by Harry Harrison, a racist colonel steals the design of the Sten submachine gun and travels back in time to change the course of The American Civil War. He is pursued by another officer, whose task isn't made easier by the fact that he's black.
• Star Trek Expanded Universe:
  • The novel Imzadi by Peter David has an aging Riker trying to change the past back to what it was, with Data trying to keep it as it was not knowing that it was changed in the first place. When the characters realize this at the end and ask the Guardian of Forever why it didn't say so sooner (potentially saving them all a lot of trouble and/or Angst), it replies (literally) "You Didn't Ask."
  • In the Strange New Worlds story "God, Fate or Fractals", it's Wesley Crusher versus a pair of Temporal Investigations agents.
• In Strike the Blood, Reina arrives in the present to stop a dragon from the future.
• Time Wars: In The Ivanhoe Gambit, Lucas and his team are sent to the 12th Century to prevent a rogue referee from damaging the timeline. The events of this novel wind up uncovering the larger conspiracy that drives the plot of the rest of the series.

Live-Action TV

• The 4400 were abducted by people from the future and returned to the present to Set Right What Once Went Wrong, while members of the anti-promicin conspiracy known as The Marked were sent back by a different future faction to thwart them.
• An episode of The Adventures of Superboy might as well be called "Terminator: The Episode". An android arrives from a distant future to kill Clark, as Clark's descendants will have ensured that the future is a utopia. To stop the android, a woman is sent to save Clark, who turns out to be quite strong herself, causing Clark to wonder if she's one of his descendants. At the end, after the android is destroyed (actually, it self-destructs after Clark fakes his death), the girl turns out to be an android herself, who explains that now that her own mission is complete, she must self-destruct as well to prevent any changes to the timeline. She only asks that Clark bury a certain component of her in a specific place for her future creator to find (i.e. an indicator that she succeeded).
• Agents of S.H.I.E.L.D.: Season 7's Story Arc is all about the Chronicoms going back in time and trying to alter history to eliminate S.H.I.E.L.D. and create a world that is less defended against their impending invasion, and the S.H.I.E.L.D. team chasing after them to try and stop it. Ultimately, the changes that the Chronicoms make build up too much for the heroes to stop, but fortunately, it turns out that the MCU's time travel rules (as established in Avengers: Endgame) apply here too, creating an Alternate Timeline separate from the main one rather than overwriting it. This turns out to all be part of Fitz's master plan to create a scenario that the team can use to defeat the Chronicoms in both timelines.
• Series two of Ashes to Ashes (2008) becomes this, with Martin Summers trying to Set Right What Once Went Wrong from his perspective, but would actually Make Wrong What Once Went Right for everyone else. Alex decides that acting as the Time Police will enable her to get home.
• Being the pop culture-fueled Fantasy Kitchen Sink that it is, Big Wolf on Campus naturally features these in one episode. An android resembling Merton, nicknamed "The Mertonator", is sent back to present-time Pleasantville to kill Tommy, who seemingly became famous enough of a hero in the future for this to occur. The Mertonator is soon followed by an android resembling Tommy, who was sent to protect him. Hilariously, when it looks like the two androids are about to have an epic beatdown, the Mertonator just reduces the Tommy android into slag, forcing the heroes to defeat it themselves.
• Castle (2009) of all things features an example. While it could have a mundane explanation, said explanation makes less sense than this. While The Stinger of the episode leaves it as an open question, the behavior of the killer makes no sense if he isn't a time traveler, as it would require that he work backwards in an extremely convoluted fashion.
• Charmed (1998): In "All Halliwell's Eve", the sisters are sent back in time to save one of their ancestors; at the same time, team evil is sending back their main agent to prevent their birth.
• Chousei Kantai Sazer X: Sazer-X travels back in time to stop Descal from conquering Earth and establishing the Neo Descal, while Neo Descal travels back in time to defeat Sazer-X and conquer the past Earth for their ancestors to ensure the timeline stays the same.
• Continuum:
  • In the pilot, 8 members of Liber8 (a terrorist movement fighting the corporate government) are sent back in time from the year 2077 to present day Vancouver, along with corporate police officer Keira Cameron. The Liber8 members, with all their skills, knowledge and futuristic upgrades, decide to topple the corrupt corporations who will eventually take control of the government, so Cameron allies with the Vancouver police to take down what temporal locals see as an emerging terrorist cell.
  • Continuum gets downright recursive with this; the initial conflict between Kiera and Liber8 generates a whole new timeline, even worse than the original 2077, and another character arrives from this timeline to prevent both Kiera and Liber8 from screwing things up further. There's also yet another time traveler, from some indeterminate point in the future, who goes to the past and founds an organization of Time Police who are trying to stop all of the above.
• Doctor Who: The whole concept of the oft-mentioned Time War in the new series, with the Time Lords themselves waging war against a galaxy-spanning Imperial Dalek fleet. The war was so big, most other species were too technologically underdeveloped to even notice.
• In season 5 of The Flash (2014), Barry and Iris's daughter Nora comes back from the future in order to save Barry, so she doesn't grow up without a father. Later on, though, it's revealed that Cicada's niece Grace has come back from another future in order to prevent her uncle from being de-powered.
• In Galactica 1980, Xavier went back to World War II to give rocket technology to the Nazis, hoping it would make Earth advanced enough to repel Cylons in 1980 but Troy and Dillon go back to stop him. Them chasing him to different time periods was originally going to be the entire show.
• In Guest from the Future, Alisa follows space pirates who in turn chase Kolya Gerasimov escaping via the time machine in order to save Mielofon from them.
• Hercules: The Legendary Journeys:
  • Subverted with "The Enforcer", in which a terminator-like woman is sent by Hera to kill Hercules but with no time-traveling involved. Its Sequel Episode even takes after Terminator 2: Judgment Day, with a fire-elemental enforcer appearing as a stand-in for T-1000 while the original enforcer is sent by Hades to protect Hercules (again with no time-traveling involved).
  • "Armageddon Now: Part 1/Part 2" has a complicated case. Callisto is sent back in time by Hope to kill Hercules' mother to prevent his being born. Iolaus is sent back in time by Ares to prevent this. While killing Hercules's mother is clearly an example of Make Wrong What Once Went Right, Callisto agrees to commit the heinous act in exchange for the chance to prevent her parents from being killed by Xena's army. That doesn't go well for her, when it turns out to be a Stable Time Loop with her killing her own family by accident.
• Kamen Rider:
  • Kamen Rider Den-O features Imagin going into the past to wreak havoc with Kamen Rider Den-O time travelling to stop them.
  • Kamen Rider Zi-O plays around with the formula a bit. At the outset, the twosome has the same goal of averting a Bad Future, but vastly different methods: Tsukuyomi finds the Evil Overlord Ohma Zi-O when he's still Ordinary High-School Student Sougo Tokiwa, warns him about the future, and tries to keep him off the path of evil. Her friend Geiz Myoukoin is willing to just straight-up murder Sougo if it means changing the future, but eventually Tsukuyomi convinces him to help guide Sougo into becoming a hero rather than a villain. There's also Woz, who came back to help Sougo become the evil overlord, and the Time Jackers who are trying to set up their own candidates for overlord. Later in the series comes a second Woz, who's from a different future than the others. Like the first Woz, he's trying to keep history the way he remembers it, only his history involves Geiz defeating Ohma Zi-O before he could come to power.
• Mirai Sentai Timeranger and its adaptation Power Rangers Time Force are about mutant criminals coming back from the year 3000, and the Time Police right behind to stop them.
• Harlan Ellison's The Outer Limits (1963) episodes "Soldier" and "Demon with a Glass Hand" may have created this trope. In fact, the producers of The Terminator had to pay a settlement to him following a lawsuit.
• Quantum Leap, in its final season, features an Evil Leaper who tries to undo the positive changes in the past wrought by Sam Beckett.
• Quantum Leap (2022) plays with this a bit. Martinez's mission on leaps isn't to sabotage Ben's leaps a la the original series' Evil Leapers; rather, he also has to Set Right What Once Went Wrong in order to leap. But at the same time, Martinez's end goal is to leap ahead and kill Ben's fiancee Addison. Ben's original intention for stepping into the accelerator — at least, according to Janis Calavicci — is actually to sabotage one of Martinez's leaps in order to prevent Martinez from leaping out, and thereby save Addison's life.
• Star Trek:
  • This is the plot of the Star Trek: Deep Space Nine episode "Trials and Tribble-ations". The villain of the TOS episode "The Trouble with Tribbles" attempts to assassinate Captain Kirk in order to alter the outcome of that episode, and our heroes need to stop him.
  • A major plot in the first seasons of Star Trek: Enterprise is the Temporal Cold War, in which various future factions use agents (some of them sent from other eras, others natives of the 22nd) to try to manipulate "historical" events in their favor.
• The Supernatural episode "The Song Remains the Same" ultimately turns out to be a Terminator Threesome. First, Anna goes back in time with the intention of averting the apocalypse by killing John and Mary Winchester before Dean and Sam can be born. Sam and Dean, with Castiel's help, follow her in order to save their parents from Anna and from their fates in the original timeline. Finally, Archangel Michael goes back to ensure that history takes its established course.
• In Terminator: The Sarah Connor Chronicles, another evil robot is sent back to kill John Connor as a teenager, and a reprogrammed robot who looks like a cute waif of a girl is sent back to protect him. Over the course of the series, other robots and human resistance fighters are also sent back. They even have conflicts between the many terminators sent back, if their tasks conflict with one another. For example, a terminator is sent to kill and replace Special Agent James Ellison. The attempt is interrupted when Cromartie, a terminator sent to find and kill John Connor, saves Ellison and destroys the other robot. When asked why by Ellison, Cromartie simply says that Ellison will lead it to the Connors. Not under duress but because Ellison is looking for them himself.
• Timeless is built around this. A terrorist and his henchmen steal an experimental time ship and set out to completely alter American history in order to root out the Ancient Conspiracy controlling the country. To stop him, the government and the private company that built the time ship gather a group of experts to go back on a prototype of the ship and prevent him from making any changes. Another twist is that Flynn, the main "terrorist", is being guided by a diary that one of the protagonists is supposed to write a few years later. In Season 2, Flynn has been imprisoned, and his time machine is now under the control of Rittenhouse, the very organization Flynn wanted to destroy.
• Time Trax is a variation. The hero Captain Darien Lambert was sent back into the past to retrieve several escaped criminals who escaped to the past with the help of a Mad Scientist named Mordecai Sahmbi. This trope applies since Sahmbi himself also escaped into the past, and several times his schemes in the past threaten to change the timeline, and the hero must stop him. Unfortunately, the show can't decide on whether the 20th century shown is actually Lambert's past or merely a time-shifted alternate universe. The main character's main problem with them is that they're escaped criminals, not that they're a danger to his timeline. He does, however, have a personal score to settle with Sahmbi for killing his Love Interest in the pilot.
• This is the central idea of Tru Calling, though by the time it's revealed that this is the case and the conflict between Tru (change the past to save people) and her counterpart (keep this past the same and let people die) is properly introduced, the show was on the verge of being cancelled, so the idea is never fully developed.
• Wonder Woman (1975): In "Time Bomb", Cassandra Loren, an expert on 20th Century history from 2155, travels back in time to Los Angeles in 1978 in order to use her knowledge of the future to make a fortune. Adam Clement follows her back to stop her.

Pinballs

• This is the premise of Terminator 3: Rise of the Machines, with the player in the role of the T-850. Symbolized in-game by the two Terminator heads on the playfield.

Tabletop Games

• One of the adventure seeds in Fate of Cthulhu has the characters run into versions of themselves sent back from an altered future to stop them from doing whatever they do.

Theatre

• Harry Potter and the Cursed Child has the Augurey go back in time to prevent Voldemort's first defeat and Harry and co. having to stop her.
• A Very Potter Musical: In A Very Potter Sequel, Lucius Malfoy travels back in time to kill Harry and prevent Voldemort's defeat. Draco hitches a ride in order to stop him.

Theme Parks

• In the now-defunct Back to the Future: The Ride formerly at Universal Studios, Doc Brown sent YOU back (and forward) in time to prevent Biff from messing up the timeline.

Toys

The mini-comics for the aborted The Powers of Grayskull Masters of the Universe toyline would have had He-Man journey to Eternia's past of "Preternia", with Skeletor following him and joining the local villain, King Hiss. Meaning He-Man had to stay and stop him.

Video Games

• In Achron, this is what happens in a standard two-player game.
• BlazBlue: The Black Beast and Hakumen are both pulled into the past by the same incident, setting up the "Groundhog Day" Loop that plays out repeatedly in the games.
• Inverted like crazy by Brütal Legend. The evil "Emperor" (actually Empress, but demons don't differentiate apparently) Succoria is sent forwards in time, along with humanity's greatest warrior Riggnarok, who has sworn to slay her and is effectively her time-travel stowaway. When she reaches the future, she suffers a Villainous BSoD when she realises that humanity wins. Instead of slaying her, Riggnarok begins to feel the inklings of pity, and, well, the road gets lonely...
• Played with both ways in Dark Chronicle: Emperor Griffon, who resides 10 thousand years into the past, is doing battle with La Résistance 100 years into the future. In order to eliminate them, he sends out his agent into the present, to destroy his enemies' settlements and erase them from existence. Enter Monica, from 100 years in the future, whose Cosmic Keystone allows her to travel back to the present. With the help of the present-day protagonist, Max, she restores her allies' "Origin Points" and preserves future history (and, in one notable case, improves upon it.) Of course, Griffon's agent Gaspard will try to thwart their efforts....
• In DC Universe Online, hero and villain players do this as they try to mess with or prevent the opposing faction from messing with the origins of iconic characters.
• In Dragon Ball Xenoverse, Towa and Mira are out to Make Wrong What Once Went Right. Time Patrol Trunks, along with you, are out to stop them and fix history. Then, after you defeat Mira, Towa retreats and Demon God Demigra takes their place.
• EarthBound (1994) displays this right at the beginning of the game. Giygas chose to stop Ness while he was still weak by sending a Starman Jr. back in time to kill him directly. Luckily for Ness, a time-travelling alien named Buzz Buzz found him first to protect him. Unfortunately, Buzz Buzz dies shortly afterward. In true Terminator fashion, it is this time-travel attack that kicks off the plot and sets Ness on the path to defeat Giygas. Happens in the endgame too: Giygas is launching his main assault in the past, so the heroes have to go there to fight him.
• Fire Emblem: Awakening features "Marth" or Lucina, as she's actually named, as well as any other child characters, sent back to prevent the Bad Future, and the actual Player Character, or at least an alternate thereof possessed by the evil dragon Grima sent to enforce it.
• In Jigsaw, the player character (known as "White") is attempting to stop "Black" from changing the past, although neither side is really in the wrong.
• The central premise of The Journeyman Project. In fact, the purpose of the Temporal Security Annex (later Temporal Security Agency) to ensure that this trope is in effect in case someone else gets ahold of a Time Machine. The sequels deal with other issues, with a temporal smuggling and looking for an ancient Precursor relic in the past.
• The Legend of Zelda:
  • Oracle of Ages has Veran, Nayru, Link, and Ralph, in a bizarre time-traveling quadrangle of Big Bad, Living MacGuffin, the hero, and The Scrappy.
  • Also happens in towards the very end of Skyward Sword, when Link and Groose follow Ghirahim back in time in order to both save Zelda and prevent the resurrection of the Demon King Demise.
• Magical Girl Lyrical Nanoha A's Portable: The Gears of Destiny has Well-Intentioned Extremist Kyrie Florian jumping back in time to retrieve an artifact that could help her scientist father save their dying planet. Idiot Hero Amitie Florian then jumps back in time to stop her, since as said father mentioned, interfering with the time stream could lead to even worse consequences than the destruction of their evacuatable planet. In addition, the both of them are also Ridiculously Human Robots.
• In Millennia: Altered Destinies, the player is given a timeship by a hooded alien to guide four races in the Echelon Galaxy in order to stop the expansion of the evil Microids. One of the major obstacles is an alternate version of the player recruited by the Microids to sabotage the player's work. Like the player, he cannot be killed. While the game is normally played in a Take Your Time manner, since you're not required to immediately rush to resolve such and such crisis, your Evil Counterpart is on San Dimas Time with you and can alter the past whenever he feels like it.
• Pokémon Mystery Dungeon: Explorers has Dusknoir and Grovyle. One is there to stop the other from plunging the world into a dark, frozen hellscape. However, the established course of the timeline is that hellscape, thus the game plays with the trope with a Villain with Good Publicity trying to stop the Hero with Bad Publicity from changing anything.
• An ongoing, chessmaster-y form of this is half the plot of Radiant Historia, with the Big Bad making minor changes to Make Wrong What Once Went Right and Stocke making similar changes to counteract them.
• Rescue Raiders does this with whole armies: one fighting to change the outcome of World War II, the other to stop them.
• The final cutscene in Star Trek: Armada has the timeship USS Premonition from the Bad Future follow a Borg sphere into the past to save the USS Enterprise-D. Luckily, the sphere is damaged and is blown up by a single torpedo volley. The Premonition then jumps into its own time, with past Picard simply noting the strange battle in the log and moving on.
• The Big Bad of TimeShift is a disgruntled scientist who uses a time-traveling suit to travel to the past and use his vast scientific knowledge to Take Over the World and establish a fascist dystopia. The player is a second scientist, also equipped with a time-traveling suit, who follows the first scientist through time in order to stop him.

Visual Novels

• Time Hollow plays a variation of this. Upon learning that the past has changed, the protagonist tries to undo the antagonist's interferences in time through time portals. The biggest conflict is trying to save the antagonist's mother, who sent herself a letter in time to commit a form of suicide.

Webcomics

• Bad Machinery's "Case of the Forked Road" has two different Power Trios taking these roles. It's made slightly more complicated by the fact that Calvin Goater has been time-travelling before them for as-yet-unspecified reasons.
• The "Surreptitious Machinations" arc of General Protection Fault draws heavily from The Terminator, taking place in a future where Empress Trudy has conquered the world, and where Nick and Ki's son Todd goes back in time to prevent the future from coming about, while the Empress herself goes back to stop him. Interestingly enough, it's revealed at the end that only by the Empress' informing her past self could the bad future come to be (which would only happen if the bad future already exists, creating a time paradox), which reverses their roles. A Terminator comes back to the present to deal with Todd, but fails early on and serves as a way to frame Fooker for murder.
• S.S.D.D. has this with two factions: the Anarchists, who are trying to orchestrate the past to result in an economic collapse leading to their rise in power, and Dr. Cook's people, who are trying to avert that. Cook's group has one cybernetically-enhanced Super-Soldier (Tessa), while the Anarchists send a series of robots and clones.
• Exaggerated in this xkcd strip. Someone is visited by their future self, warning them to not watch Terminator: Dark Fate. Then, their other future self appears, this time from a timeline where they regret not watching the movie, convincing the present self to go see it with them. And then the future selves are visited by their future selves, wanting to stop them both. The comic eventually devolves as more and more future selves arrive, including one who wants to kill Hitler but got the year wrong.

Western Animation

• Replace individual with faction and this is the plot of the third season of Beast Wars, when it turns out that Megatron's plan to go back in time to destroy Optimus Prime didn't go as completely Off the Rails as initially thought.
• The Family Guy episode "PeTerminator" has a terminator (who takes the form of Peter) sent from the future to kill Stewie, due to the future war between the latter and Brian that stemmed from a comment on an Instagram post. Not to mention the terminator Lois, who appears to be a stand-in for T-1000. The title sequence for the episode even has all the characters as flaming skeletons as if Judgement Day occurred, as dramatic music plays and the camera pans across the devastation.
• The second series of Gadget Boy & Heather, "Gadget Boy's Adventures in history": Heroic trio versus four villains.
• Jackie Chan Adventures did this with a Future Badass version of Jade and Shendu's Kid from the Future, Drago, in "J2". Future Jade's arrival was even accompanied by Terminator-style music.
• Masters of the Universe:
  • In the He-Man and the Masters of the Universe (1983) episode "The Time Corridor", He-Man, Man-At-Arms, Orko and Battle Cat have to travel back to Preternia to stop Skeletor destroying Castle Grayskull with the Wheel of Infinity.
  • The New Adventures of He-Man has He-Man being summoned to the future to save the planet Primus. Needless to say, Skeletor follows him and joins the bad guys.
• Megas XLR:
  • One episode revolves around Gorrath's second-in-command's plan to kill a current-day ancestor of Kiva, as Kiva and Jamie try to protect her.
  • The show's main plot has shades of this as well: Kiva and MEGAS are sent back in time (further back than expected) and the Glorft commander followed her.
• My Little Pony: Friendship Is Magic: In the fifth season finale, "The Cutie Re-Mark - Part 1/Part 2", Starlight Glimmer travels back in time to prevent Rainbow Dash from performing a Sonic Rainboom as a child, which would alter the fates of the main characters and prevent them from stopping various dangers in the future. Twilight and Spike follow her into the past to make sure that the Rainboom goes off like it was supposed to.
• Rick and Morty: Spoofed left and right in "Rattlestar Ricklactica".
  • A dozen snake terminators get sent back in time to eliminate the ape child Morty in order to protect the timeline. Meanwhile, the Snake Resistance sends its own terminator to protect Morty from Serpacorp.
  • A similar scenario unfolds on the snake planet with hordes of opposing terminators battling over the alien snake and her brood.
  • Happens again with the battle over snake Hitler.
• Superfriends: In "Return of the Phantoms", three Kryptonian criminals travel back in time to kill Superboy so his older self Superman will not exist and he would have never trapped them in the Phantom Zone. Superman and Green Lantern travel back to stop them.
• The Superman: The Animated Series episode "New Kids in Town" has a crossover with the Legion of Super-Heroes in which Cosmic Boy, Saturn Girl, and Chameleon Boy protect a young Clark Kent from a time-travelling Brainiac. Clark winds up teleporting Brainiac into the sun.
• Teen Titans (2003): In a variant, Warp from the far future is followed through a time-gate by Starfire from the present, and she winds up hunting for him Twenty Minutes into the Bad Future.
• X-Men: The Animated Series:
  • A two-episode arc involves Bishop traveling from the Bad Future to the present day, attempting to prevent the outbreak of a mutant plague. He succeeds, but his actions backfire and result in the deaths of the X-Men and the complete extinction (rather than just decimation) of mutants. Specifically, the vaccine that was created to counter the plague was also needed by future mutants to survive and due to Bishop's actions, it was never created — so Cable comes from an even further future to stop Bishop. Cause the mutant plague or stop the mutant plague? Nah, Cable takes a third option: Infect Wolverine with the plague, letting his Healing Factor develop the vaccine, then destroy the plague.
  • You've also got the more basic variety in most Time Travel episodes. First it's Bishop and Nimrod, then it's the Cable and Bishop thing, then it's Bishop and Fitzroy, then it's Shard and the various agents of Apocalypse (though they're from the present, Apocalypse is the version from Cable's future). In the end, the Bad Future is not prevented, but at least they always managed to stop those who'd make it any worse.

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