History Main / CantLiveWithoutYou

* ''WesternAnimation/{{Centaurworld}}'' has [[spoiler:The Nowhere King and the General. Originally an elktaur who separated himself into his human and elk halves to be with a princess he fell in love with (a.k.a. The Mysterious Woman), the human half went on to become the General and marry the Woman while the elktaur's consciousness was trapped in his elk half. When the General tried to drown the Elk after the Elk threatens to expose the truth, the General only relents when he learns that killing the Elk meant killing himself. Instead, he imprisons the Elk in a windowless cell too small to even stand in for ''ten years.'' This, combined with despair from never seeing the Woman again and having nowhere to belong, would lead to him becoming The Nowhere King.]]

%% The examples have been alphabetized. Please put any new example in its proper place in the folder rather than at the end.

%%
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[[folder:Anime & Manga]]
* ''Manga/AhMyGoddess'' has the doublet system, in which random pairs from heaven and hell are linked. If one dies, the other dies. After they are linked, their memories are erased -- the purpose being so if you kill someone on the other side, you don't know which of your allies would die (it could be you, natch).
* Arthur and Shalott in ''Manga/AirGear''; Shalott was almost killed when another character kicked through his chest, [[ArtisticLicenseBiology damaging all his vital organs]], so Arthur's organs were transplanted into Shalott. Now Arthur has no organs, so he's dependent on a literal blood connection between him and Shalott for feeding and waste elimination, and will die in a couple hours if the connection is interrupted.
* In one chapter of ''Manga/BlackJack'', the title doctor surgically attaches a young boy with lungs weakened by heart disease to his mother until he can get an organ donor.
* ''Manga/{{Bleach}}'': The filler Bount arc features Dolls, the Bounts' EmpathicWeapon. Similar to Zanpakutō, but the Bount and Doll are more linked; if one dies, so does the other.
* Elraine and Kiri of ''Manga/DoubleArts'', must always be physically touching (normally holding hands) or Elraine will die of the disease she's infected with but he's immune to and staves off.
* ''Franchise/DragonBall'':
** ''Anime/DragonBallZ'':
*** If Piccolo were to die, then Kami would as well and vice-versa. This is because they were originally one person but Kami cast off his evilness in order to become guardian of Earth. That evilness turned into Piccolo. On the plus side, you only have to resurrect one to get both back. This is no longer an issue once the two of them [[FusionDance fuse back into one being]].
*** Shenron and Porunga also cease to exist (and their respective Dragon Balls turn to stone) if their creator dies, though the connection can be passed on before the creator dies (and the dragon can even be recreated after if the original materials are found). For Shenron, that's Kami, later replaced by Dende after Kami fuses with Piccolo. For Porunga, that's Grand Elder Guru, later replaced by Elder Moori after Guru passes away.
** ''Anime/DragonBallSuper'':
*** Similarly, it's revealed that if [[spoiler:the Supreme Kai of any universe]] were to die, so would a God of Destruction of that universe. The reverse is, presumably, true. Goku surmises that he could defeat the latter if he defeated the former, but then decides that wouldn't be any fun. [[spoiler:Beerus]] is less than amused.
*** [[spoiler:Whis]] also cannot exist without a [[spoiler:God of Destruction]] around, so if [[spoiler:Beerus]] dies, [[spoiler:Whis]] will cease to function until someone else takes up the role. [[spoiler:This is probably why he asked Goku and Vegeta if they wanted to replace Beerus if he dies, as a backup plan for if it happens.]]
* This is the case for Eureka in the ''Anime/EurekaSeven'' movie ending when she [[spoiler:was reborn as a human being]]. She stated that she could only exist as long as Renton lives and dreams.
* ''Manga/FairyTail'': Since the Books of Zeref channel their creator's magic, if Zeref were to die, the Etherious will die with him. [[spoiler:This includes E.N.D., which is why Happy prevents Natsu from landing a possible finishing blow on his brother/creator after learning the truth of his origins]].
* ''Manga/InuYasha'': According to Naraku's final detachment Byakuya, even if his other "siblings" had survived, they would have perished if/when Naraku was destroyed anyway.
* In ''[[Manga/Reborn2004 Reborn!]]'', one character, [[spoiler: Chrome Dokuro]] can live only because [[spoiler:her organs, the originals of which have been removed, are physical illusions cast by Mukuro Rokudo]].
* Mizumi of ''Manga/ReturnToLabyrinth'' can remove an aspect of a person's personality to make a clone but if the original dies, then so does the clone and vice versa.
* ''Anime/SailorMoon'': If the Maijuku dies, Al and En go down as well. Or as En's Creator/DiCEntertainment dub counterpart explains, "if the Tree ''dies'', ALAN, ''we'' die!"
* ''Sequence'', by Saenagi Ryou, starts out with the main character, [[OrdinaryHighschoolStudent Kanata]], accidentally freeing a [[BadassAdorable young imprisoned vampire]], and getting his heart ripped out for his trouble. The vampire, who isn't actually a bad [[AmbiguousGender person]], ties their life forces together to keep Kanata alive.
* [[spoiler:Fai and Kurogane]] in ''Manga/TsubasaReservoirChronicle''; the former can't live without the latter, since, [[spoiler:as a vampire, Fai's dependent on blood for feeding, and can only feed on Kurogane.]]
* Charlie in ''Manga/{{Vassalord}}'' is a vampire who is dependent on blood from his master Rayflo because, due to Charlie's religious views, he refuses to drink from humans since he sees it as a cardinal sin. (Drinking from Rayflo is also a sin, but in Charlie's eyes it's the lesser of two evils.)
* In ''Manga/TheWorldGodOnlyKnows'', Elsie and Keima share collars/chokers that dictate that if one dies, the other will as well, no matter what they die from.
[[/folder]]

[[folder:Fan Works]]
* In ''Fanfic/BeingDeadAintEasy'', Yami Bakura reveals that [[spoiler:since Kaiba bonded Joey's soul to his own, Joey has been slowly killing Kaiba as his own condition worsens]].
[[/folder]]

[[folder:Literature]]
* ''Literature/TheCampHalfBloodSeries'': Inverted in ''Literature/PercyJacksonAndTheOlympians'': [[spoiler:Instead of a person being dependent on an object, it's the other way around -- the Labyrinth can't survive without Daedalus.]]
* ''Literature/CerberusHighAnotherStory'', which takes place in an AlternateUniverse from the [[Literature/CerberusHigh first book]] in which Kazuki does not exist, describes Oralee's subsequent absence by implying that the two of them cannot exist without one another in the same way that [[LightDarknessJuxtaposition light cannot exist without darkness]].
* In the ''Literature/ChaosGods'' series, a ritual called a Binding allows two people to share their souls and energies. This allows each to draw upon the strengths of the other; but it also means that if one dies, so will the other. Several important characters are Bound, including Ki's parents and De's parents.
* ''Literature/DragonridersOfPern''
** The dragons are symbiotes who literally can't face life without their rider: a dragon who fails to find a compatible rider upon hatching will die. If they bond to a rider and the rider dies, the psychological trauma causes the dragon to cross the DespairEventHorizon and commit suicide. The only exception is a queen dragon whose rider dies while the dragon is waiting for eggs to hatch -- she'll wait until just before Hatching to go ''Between'', and in the intervening time she won't leave her eggs, even to feed herself.
** The riders don't fare much better if their dragons die. One rider went ''Between'' with the above-mentioned queen dragon since the queen dragon's rider was riding the first rider's dragon (an older queen dragon) and they made the fatal mistake of going ''Between'' when they were already exhausted from doing so multiple times. Other riders in the series have been reduced to a child-like state [[spoiler:(Kylara)]] or have been driven insane with rage [[spoiler:(T'Kul)]]. Going through the rest of their lives as shadows of their former selves devoting themselves to other causes to remain sane [[spoiler:(Lytol and Brekke)]] is the ''best'' case scenario.
* In ''Literature/TheFiresStone'', to ensure Aaron doesn't run off or otherwise kill Darvish, his soul is linked to the prince's so not only will they die together, but they can't even get very far from each other.
* Inverted in ''Literature/HarryPotter'', as the prophecy in the fifth books points out, "Neither can live while the other survives." However, you could say that it is played straight, [[spoiler:as Harry is an unintentional horcrux. When Voldemort kills him, he seals his own death.]]
* Humans and their daemons in ''Literature/HisDarkMaterials''. A slight variation, in that it is possible to separate a daemon from their human with specialist equipment. In this case, both survive, but both are reduced to shadows of their former selves, as the daemon represents the human's soul. Separating them by any other means is fatal to both.
* In the ''Literature/HonorHarrington'' novels, it is common for bonded treecats to suicide after their human partner, or treecat romantic partner, dies. Since the natural lifespan of a treecat is considerably longer than that of a (pre-prolong) human, the bonding pretty much meant that bonding with a human meant that the treecat would sacrifice many decades of their lifespan. It is also stated that a human whose 'cat dies is likely to give up on their own life as well.
* In ''Literature/HowlsMovingCastle'' by Creator/DianaWynneJones (and [[Anime/HowlsMovingCastle the film of the book]] by Creator/HayaoMiyazaki), a magical contract binds Howl and Calcifer together. So, as is often referenced when Calcifer talks to Sophie, "If I die, Howl dies too."
* Due to plot complications involving the source of his agelessness, the eponymous protagonist of the German pulp series ''Literature/ProfessorZamorra'' has recently (as of this writing) become dependent on his friend Rhett Saris not so much to stay alive as to keep his ''youth''; without him, he would revert to his actual chronological age, which while not actually enough to kill him -- the series hasn't run quite that long yet -- probably would force him to retire from fighting the various forces of evil. (This is complicated by the fact that Rhett himself might yet end up turning into a fairly major demon himself if one of Hell's long-term plans is ever allowed to reach fruition... and they both know it.)
* In the first ''Literature/{{Neogicia}}'' novel, Saly, the protagonist undergoes BioAugmentation and wakes up with a second level of consciousness that seems to have developped to avoid sensory overload. In the second, [[spoiler:it turns out to be actually be an entity using her as host body, which fills very specific critera seldom found in the general population. That entity is ready to go to lengths much greater that what Saly would consider acceptable to keep her alive and can take over in an emergency. The fact the entity does sensory overload prevention in Saly even when dormant creates an downplayed mutual need]].
* The Maternity Spell in the ''Literature/SwordOfTruth'' series does this as part of its {{Synchronization}} effect. It links the caster and the target such that whatever physically happens to one happens to the other -- if the caster is punched in the nose, the target gets a nosebleed. So if the caster is killed...
* In ''Literature/{{Watersong}}'', there must always be four sirens, and they must always remain close to one another. If one of the sirens spends more than a few weeks away from the others, or if a siren dies without being replaced by the next full moon, all will perish.
* ''Literature/TheWheelOfTime'': Aes Sedai and their Warders have a {{Downplayed}} version of this bond. If a Warder kicks it, the Aes Sedai will be hit with pretty fierce depression, occasionally bordering on suicidal. Warders who lose their Aes Sedai generally go whole hog, becoming {{Death Seeker}}s against either the person who killed their partner or just whatever's at hand. It's very, very difficult to keep a surviving Warder alive, and it almost always requires extreme measures.
[[/folder]]

[[folder:Video Games]]
* Played straight with Jacob and Esau in ''VideoGame/TheBindingOfIsaac''. A player character who consists of two brothers controlled together. They each have a separate healthbar, but one dying ends the run even if the other has health remaining.
* In ''VideoGame/BioShock2'' it is revealed that if an Alpha Model Big Daddy (the PlayerCharacter in the second game, different from the Big Daddies encountered in the first game) is too far away from his Little Sister, he either dies or lapses into a coma.
* Alcatraz in ''[[VideoGame/{{Crysis}} Crysis 2]]'' is only kept alive by the Nanosuit, and even then, just barely. At a couple of points in the game the player has to use the suit's defibrillator system to revive him. Though the suit ends up being less of a life support system and more of a symbiote over the course of the game.
* In ''VideoGame/DigimonSurvive'', if [[DarkerAndEdgier a human Tamer dies]], their Digimon partner vanishes with them.
* ''VideoGame/DragonAgeOrigins'': Wynne is dependent on a friendly Fade spirit to keep her alive.
* Similar but opposite to ''Pern'' cycle, the Bond in ''VideoGame/{{Drakan}}'' series connects the dragon and his rider in such way that if the dragon dies, so does the rider, but not vice-versa (justified by the fact that dragons are just that much more powerful). Arokh, for example, has outlived at least one rider already.
* In ''VideoGame/{{Drakengard}}'', making a Pact not only binds a human with a magical entity for mutual power, but also takes a price branding a seal on what was taken.
* In ''VideoGame/EnslavedOdysseyToTheWest'', the player character is forcibly bonded to a DamselInDistress GadgeteerGenius via a RestrainingBolt that will crush his skull if he disobeys her or she dies, because she can't survive in the killbot-infested wasteland on their own.
* In the Dead Money DLC of ''VideoGame/FalloutNewVegas'', [[BigBad Elijah]] links the {{Explosive Leash}}es of you and your companions so that you don't try and betray each other.
* In ''VideoGame/FinalFantasyIV'', the death of a summoned monster results in the death of the Summoner. This is how [[spoiler:Rydia's mother]] dies early in the game. Once it returns to the realm of summoned monsters, the Summoner can no longer be harmed by its death. Which is likely why Rydia always has her monsters show up for a single attack and then teleport away.
* Late in ''VideoGame/KidIcarusUprising'' Dark Pit discovers that if anything serious happens to Pit, he's affected by it too, and makes keeping Pit alive his top priority.
* In ''VideoGame/KnightsOfTheOldRepublicIITheSithLords'', the player character and his mentor Kreia are linked by a Force Bond, gaining each other strengths and weaknesses. This isn't exactly convenient - in particular, the player is made aware of the bond when Kreia loses a hand fighting the apparent BigBad Darth Sion to keep him at bay, and the player character half the ship away at this point immediately recoils in pain as if their hand got lopped off -- so getting rid of it is one of the major plot points. [[spoiler:In the end, when Kreia turns out to be TheManBehindTheMan, she uses this as the player character's incentive to follow her to the final planet in the game -- if they try to run or hide, Kreia will kill herself and thus also kill the PC no matter where they may be.]]
* In the ending for ''VideoGame/TalesOfDestiny2'', [[spoiler:Reala]] dies along with the final boss Elraine when Kyle destroys the huge lens, as it is the only way to ensure the demise of Elraine, much to the dismay of Kyle. Although in the restarted timeline, [[spoiler:thanks to ThePowerOfLove, Reala is miraculously reborn and reunited with Kyle at the place where they met for the first time.]]
* The Destiny Bond move from ''Franchise/{{Pokemon}}'' means that if the opponent's next move causes you to faint then so will they.
* In ''VideoGame/TheWorldEndsWithYou'', if a Player is erased, their partner is as well in seven minutes unless they make a new pact with a different denizen of the Underground.
* In ''VideoGame/XenobladeChronicles2,'' if a Driver dies, then all [[EmpathicWeapon Blades]] they've resonated with will return to their [[HeartDrive Core Crystals]], [[DeathOfPersonality never to remember their past lives upon reawakening ever again.]] If a Blade were to share a piece of their Core Crystal with their Driver [[spoiler: or if they were to infuse human cells into their being to become Flesh Eaters]], then [[DeaderThanDead they risk dying for good.]]
* In the second ''VideoGame/ZoneOfTheEnders'' game, the protagonist Dingo is critically injured and linked to [[GiantRobot Jehuty]] so he can live, at the expense of not being able to survive outside of Jehuty.
[[/folder]]

%% Image removed per Image Pickin' thread: https://tvtropes.org/pmwiki/posts.php?discussion=1312703082083360200
%% Please start a new thread if you'd like to suggest an image.

!!Examples

* ''Anime/SailorMoon'': If the Maijuku dies, Al and En go down as well. Or as En's Creator/DiCEntertainment dub counterpart explains, "if the Tree ''dies'', ALAN, ''we'' die!"
* [[spoiler:Fai and Kurogane]] in ''Manga/TsubasaReservoirChronicle''; the former can't live without the latter, since, [[spoiler:as a vampire, Fai's dependent on blood for feeding, and can only feed on Kurogane.]]
* Arthur and Shalott in ''Manga/AirGear''; Shalott was almost killed when another character kicked through his chest, [[ArtisticLicenseBiology damaging all his vital organs]], so Arthur's organs were transplanted into Shalott. Now Arthur has no organs, so he's dependent on a literal blood connection between him and Shalott for feeding and waste elimination, and will die in a couple hours if the connection is interrupted.

* In ''Manga/Reborn2004'', one character, [[spoiler: Chrome Dokuro]] can live only because [[spoiler:her organs, the originals of which have been removed, are physical illusions cast by Mukuro Rokudo]].
* In one chapter of ''Manga/BlackJack'', the title doctor surgically attaches a young boy with lungs weakened by heart disease to his mother until he can get an organ donor.
* ''Manga/AhMyGoddess'' has the doublet system, in which random pairs from heaven and hell are linked. If one dies, the other dies. After they are linked, their memories are erased -- the purpose being so if you kill someone on the other side, you don't know which of your allies would die (it could be you, natch).
* ''Anime/DragonBallZ'':
** If Piccolo were to die, then Kami would as well and vice-versa. This is because they were originally one person but Kami cast off his evilness in order to become guardian of Earth. That evilness turned into Piccolo. On the plus side, you only have to resurrect one to get both back. This is no longer an issue once the two of them [[FusionDance fuse back into one being]].
** Shenron and Porunga also cease to exist (and their respective Dragon Balls turn to stone) if their creator dies, though the connection can be passed on before the creator dies (and the dragon can even be recreated after if the original materials are found). For Shenron, that's Kami, later replaced by Dende after Kami fuses with Piccolo. For Porunga, that's Grand Elder Guru, later replaced by Elder Moori after Guru passes away.
* Similarly, in ''Anime/DragonBallSuper'', it's revealed that if [[spoiler:the Supreme Kai of any universe]] were to die, so would a God of Destruction of that universe. The reverse is, presumably, true. Goku surmises that he could defeat the latter if he defeated the former, but then decides that wouldn't be any fun. [[spoiler:Beerus]] is less than amused.
** [[spoiler:Whis]] also cannot exist without a [[spoiler:God of Destruction]] around, so if [[spoiler:Beerus]] dies, [[spoiler:Whis]] will cease to function until someone else takes up the role. [[spoiler:This is probably why he asked Goku and Vegeta if they wanted to replace Beerus if he dies, as a backup plan for if it happens.]]
* ''Sequence'', by Saenagi Ryou, starts out with the main character, [[OrdinaryHighschoolStudent Kanata]], accidentally freeing a [[BadassAdorable young imprisoned vampire]], and getting his heart ripped out for his trouble. The vampire, who isn't actually a bad [[AmbiguousGender person]], ties their life forces together to keep Kanata alive.
* This is the case for Eureka in the ''Anime/EurekaSeven'' movie ending when she [[spoiler:was reborn as a human being]]. She stated that she could only exist as long as Renton lives and dreams.

* ''Manga/InuYasha'': According to Naraku's final detachment Byakuya, even if his other "siblings" had survived, they would have perished if/when Naraku was destroyed anyway.
* ''Manga/FairyTail'': Since the Books of Zeref channel their creator's magic, if Zeref were to die, the Etherious will die with him. [[spoiler:This includes E.N.D., which is why Happy prevents Natsu from landing a possible finishing blow on his brother/creator after learning the truth of his origins]].
* Mizumi of ''Manga/ReturnToLabyrinth'' can remove an aspect of a person's personality to make a clone but if the original dies, then so does the clone and vice versa.

* In the Franchise/MarvelUniverse, villainous duo Hammer and Anvil were linked by an alien device that gave them superpowers but also linked their life force. When one was shot in the head, the other also died.
* ComicBook/CloakAndDagger of the same universe depend on each other a little less dramatically -- without the countervailing influence of the other's powers, each would go (respectively) terminally depressive or destructively manic from the effect of their own.

* The titular ''Film/{{Pumpkinhead}}'' is a demonic entity brought forth to wreak vengeance on those who wronged the summoner, and the only way to put it down before it completes the task is to kill the one who summoned it.

* In ''Literature/HowlsMovingCastle'' by Creator/DianaWynneJones (and [[Anime/HowlsMovingCastle the film of the book]] by Creator/HayaoMiyazaki), a magical contract binds Howl and Calcifer together. So, as is often referenced when Calcifer talks to Sophie, "If I die, Howl dies too."

* ''Literature/TheWheelOfTime'': Aes Sedai and their Warders have a {{Downplayed}} version of this bond. If a Warder kicks it, the Aes Sedai will be hit with pretty fierce depression, occasionally bordering on suicidal. Warders who lose their Aes Sedai generally go whole hog, becoming {{Death Seeker}}s against either the person who killed their partner or just whatever's at hand. It's very, very difficult to keep a surviving Warder alive, and it almost always requires extreme measures.
* Inverted in ''Literature/PercyJacksonAndTheOlympians'': [[spoiler:Instead of a person being dependent on an object, it's the other way around -- the Labyrinth can't survive without Daedalus.]]
* Due to plot complications involving the source of his agelessness, the eponymous protagonist of the German pulp series ''Literature/ProfessorZamorra'' has recently (as of this writing) become dependent on his friend Rhett Saris not so much to stay alive as to keep his ''youth''; without him, he would revert to his actual chronological age, which while not actually enough to kill him -- the series hasn't run quite that long yet -- probably would force him to retire from fighting the various forces of evil. (This is complicated by the fact that Rhett himself might yet end up turning into a fairly major demon himself if one of Hell's long-term plans is ever allowed to reach fruition...and they both know it.)
* In the ''Literature/HonorHarrington'' novels, it is common for bonded treecats to suicide after their human partner, or treecat romantic partner, dies. Since the natural lifespan of a treecat is considerably longer than that of a (pre-prolong) human, the bonding pretty much meant that bonding with a human meant that the treecat would sacrifice many decades of their lifespan. It is also stated that a human whose 'cat dies is likely to give up on their own life as well.

* The Maternity Spell in the ''Literature/SwordOfTruth'' series does this as part of its synchronization effect. It links the caster and the target such that whatever physically happens to one happens to the other -- if the caster is punched in the nose, the target gets a nosebleed. So if the caster is killed...
* In ''Literature/{{Watersong}}'', there must always be four sirens, and they must always remain close to one another. If one of the sirens spends more than a few weeks away from the others, or if a siren dies without being replaced by the next full moon, all will perish.

* In the ''Literature/ChaosGods'' series, a ritual called a Binding allows two people to share their souls and energies. This allows each to draw upon the strengths of the other; but it also means that if one dies, so will the other. Several important characters are Bound, including Ki's parents and De's parents.

** ''Franchise/StarTrek'' seems to love this one. The Bynars are a race of cyborgs who always live and work in pairs and can't function alone.
* ''Series/{{Farscape}}'' used synchronizing bracelets for a few episodes involving negotiations.
* ''Series/RedDwarf'': The episode "Entangled" reveals this to be the case for Rimmer and Lister; if Lister dies, Rimmer's hologram is shut off in response.

* The Greek myth of Meleager involves a woman giving birth to a son, but she overheard the Fates saying that his life was linked to a piece of wood in the fireplace (already burned halfway through). She quickly took it out and extinguished it, saving his life. Years later, the son got in an argument with his maternal uncle and killed him... [[KillItWithFire Fwoosh.]]

** 4th Edition has an entire race built on this -- the Dvati, a species consisting completely of identical twins, with "souls that burn so brightly one body is not enough to contain them". They don't share damage exactly, but are played as one character (with their HP divided in half between two bodies) and have some limitations on what both can do in one round. If one Dvati twin dies, the other takes unhealable ability damage from the shock and loss of the other half of their soul until either they die too or the other twin is [[BackFromTheDead raised/resurrected]].

* In the second ''VideoGame/ZoneOfTheEnders'' game, the protagonist Dingo is critically injured and linked to [[GiantRobot Jehuty]] so he can live, at the expense of not being able to survive outside of Jehuty.

* In ''VideoGame/KnightsOfTheOldRepublicIITheSithLords'', the player character and his mentor Kreia are linked by a Force Bond, gaining each other strengths and weaknesses. This isn't exactly convenient - in particular, the player is made aware of the bond when Kreia loses a hand fighting the apparent BigBad Darth Sion to keep him at bay, and the player character half the ship away at this point immediately recoils in pain as if their hand got lopped off -- so getting rid of it is one of the major plot points. [[spoiler:In the end, when Kreia turns out to be TheManBehindTheMan, she uses this as the player character's incentive to follow her to the final planet in the game -- if they try to run or hide, Kreia will kill herself and thus also kill the PC no matter where they may be.]]

* Alcatraz in ''[[VideoGame/{{Crysis}} Crysis 2]]'' is only kept alive by the Nanosuit, and even then, just barely. At a couple of points in the game the player has to use the suit's defibrillator system to revive him. Though the suit ends up being less of a life support system and more of a symbiote over the course of the game.
* Late in ''VideoGame/KidIcarusUprising'' Dark Pit discovers that if anything serious happens to Pit, he's affected by it too, and makes keeping Pit alive his top priority.
* In the Dead Money DLC of ''VideoGame/FalloutNewVegas'', [[BigBad Elijah]] links the {{Explosive Leash}}es of you and your companions so that you don't try and betray each other.
* In ''VideoGame/TheWorldEndsWithYou'', if a Player is erased, their partner is as well in seven minutes unless they make a new pact with a different denizen of the Underground.

* Played straight with Jacob and Esau in ''VideoGame/TheBindingOfIsaac''. A player character who consists of two brothers controlled together. They each have a separate healthbar, but one dying ends the run even if the other has health remaining.

[[folder:Web Comics]]

* In ''WesternAnimation/StevenUniverse'', [[spoiler:Steven's Gem is essentially his life force. After it was forcefully removed by White Diamond, it forms a HardLight body of its own while his organic body turns pale and becomes weak to the point he can't stand and can barely talk, requiring Connie's help to reunite with his Gem.]]

* In one episode of ''WesternAnimation/Ben10'', Ben and Kevin are captured and forced into GladiatorGames. They are shackled together by an energy shackle so that if one dies, the other does too.

* ''WesternAnimation/{{Gargoyles}}'': While Demona and Macbeth have ResurrectiveImmortality against every thing else, were one of them to kill the other, both would die.
* Max and Steel in the rebooted version of ''WesternAnimation/{{Max Steel|2013}}''. Without Max, Steel will run out of power and shut down for good. Without Steel, Max would basically explode.
* ''WesternAnimation/{{Centaurworld}}'' has [[spoiler:The Nowhere King and the General. Originally an elktaur who separated himself into his human and elk halves to be with a princess he fell in love with (a.k.a. The Mysterious Woman), the human half went on to become the General and marry the Woman while the elktaur's consciousness was trapped in his elk half. When the General tried to drown the Elk after the Elk threatens to expose the truth, the General only relents when he learns that killing the Elk meant killing himself. Instead, he imprisons the Elk in a windowless cell too small to even stand in for ''ten years.'' This, combined with despair from never seeing the Woman again and having nowhere to belong, would lead to him becoming The Nowhere King.]]

* ''Anime/SailorMoon'': If the Maijuku dies, Al and En go down as well. Or as En's dub counterpart explains, "if the Tree ''dies'', ALAN, ''we'' die!"

** Some races in ''D&D'' have their LifeForce linked to an item, plant or place, mostly nature spirits or descendants of some such, with direct inspiration from folklore or mythology. Nereids carry a shawl that contains their soul, and someone seizing it and threatening to destroy it can control the creature. Dryads and Hamadryads are linked to a single tree in the forest. Bamboo and River Spirit Folks, from the ''Oriental Adventures'', are synchronized with a specific bamboo grove or river, respectively. Damaging a linked tree or place will weaken or wound those spirits, and destroying it will kill them.

* ''WesternAnimation/{{Centaurworld}}'' has [[spoiler:The Nowhere King and the General. Originally an elktaur who separated himself into his human and elk halves to be with a princess he fell in love with (a.k.a. The Mysterious Woman), the human half went on to become the General and marry the Woman while the elktaur's consciousness was trapped in his elk half. When the General tried to drown the Elk after the Elk threatens to tell the truth, the General only relents when he learns that killing the Elk meant killing himself. Instead, he imprisons the Elk in a windowless cell too small to even stand in for ''ten years.'' This, combined with despair from never seeing the Woman again and having nowhere to belong, would lead to him becoming The Nowhere King.]]

* ''WesternAnimation/{{Centaurworld}}'' has [[spoiler:The Nowhere King and the General. Originally an elktaur who separated himself into his human and elk halves to be with a princess he fell in love with (a.k.a. The Mysterious Woman), the human half went on to become the General and marry the Woman while the elktaur's consciousness was trapped in his elk half. When the General tried to drown the Elk half after the Elk threatens to tell the truth, the General only relents when he learns that killing the Elk meant killing himself. Instead, he imprisons the Elk in a windowless cell too small to even stand in for ''ten years.'' This, combined with despair from never seeing the Woman again and having nowhere to belong, would lead to him becoming The Nowhere King.]]

* ''WesternAnimation/{{Centaurworld}} has [[spoiler:The Nowhere King and the General. Originally an elktaur who separated himself into his human and elk halves to be with a princess he fell in love with (a.k.a. The Mysterious Woman), the human half went on to become the General and marry the Woman while the elktaur's consciousness was trapped in his elk half. When the General tried to drown the Elk half after the Elk threatens to tell the truth, the General only relents when he learns that killing the Elk meant killing himself. Instead, he imprisons the Elk in a windowless cell too small to even stand in for ''ten years''. This, combined with the despair of never seeing the Woman again, would lead to the Elk becoming The Nowhere King.]]

This trope is not about people who can't stand to live apart from each other but are still physically able to do so; for those, head over to either LivingEmotionalCrutch or IfICantHaveYou. See also SoulJar when it also gives a form of immortality. Also note that this is unrelated to CantLiveWithThemCantLiveWithoutThem.

* In the first ''Literature/{{Neogicia}}'' novel, Saly, the protagonist undergoes BioAugmentation and wakes up with a second level of consciousness that seems to have developped to avoid sensory overload. In the second, [[spoiler:it turns out to be actually be an entity using her as host body, which fills very specific critera seldom found in the general population. That entity is ready to go to lengths much greater that what Saly would consider acceptable to keep her alive and can take over in an emergency. The fact Saly it does sensory overload prevention in Saly even when dormant creates an downplayed mutual need]].

* In ''VideoGame/XenobladeChronicles2,'' if a Driver dies, then all [[EmpathicWeapon Blades]] they've resonated with will return to their [[HeartDrive Core Crystals]], [[DeathOfPersonality never to remember their past lives upon reawakening ever again.]] If a Blade were to share a piece of their Core Crystal with their Driver [[spoiler: or if they were to infuse human cells into their being to become Flesh Eaters]], then [[FinalDeath they risk dying for good.]]
* Played straight with Jacob and Esau in ''VideoGame/TheBindingOfIsaac''.

* In ''WesternAnimation/StevenUniverse'', [[spoiler:Steven's Gem is essentially his life force. After it was forcefully removed by White Diamond, his body turns pale and becomes weak to the point he can't stand and can barely talk, requiring Connie's help to reunite with his Gem.]]

* In ''Literature/CerberusHighAnotherStory'', it is explained that Oralee and Kazuki cannot exist without one another as [[LightDarknessJuxtaposition light cannot exist without darkness]].

* In ''VideoGame/KnightsOfTheOldRepublicII'', the player character and his mentor Kreia are linked by a Force Bond, gaining each other strengths and weaknesses. This isn't exactly convenient - in particular, the player is made aware of the bond when Kreia loses a hand fighting the apparent BigBad Darth Sion to keep him at bay, and the player character half the ship away at this point immediately recoils in pain as if their hand got lopped off -- so getting rid of it is one of the major plot points. [[spoiler:In the end, when Kreia turns out to be TheManBehindTheMan, she uses this as the player character's incentive to follow her to the final planet in the game -- if they try to run or hide, Kreia will kill herself and thus also kill the PC no matter where they may be.]]

This trope is not about people who can't stand to live apart from each other but are still physically able to do so; for those, head over to either LivingEmotionalCrutch or IfICantHaveYou. See also SoulJar when it also gives a form of immortality. Also note that this is unrelated to CantStandThemCantLiveWithoutThem.

* In ''Manga/KatekyoHitmanReborn'', one character, [[spoiler: Chrome Dokuro]] can live only because [[spoiler:her organs, the originals of which have been removed, are physical illusions cast by Mukuro Rokudo]].

* In ''VideoGame/Drakengard'', making a Pact not only binds a human with a magical entity for mutual power, but also takes a price branding a seal on what was taken.

* In ''VideoGame/KnightsOfTheOldRepublicII'', the player character and his mentor Kreia are linked by a Force Bond, gaining each other strengths and weaknesses. This isn't exactly convenient - in particular, the player is made aware of the bond when Kreia loses a hand fighting the apparent BigBad Darth Sion to keep him at bay, and the player character half the ship away at this point immediately recoils in pain as if their hand got lopped off - so getting rid of it is one of the major plot points. [[spoiler:In the end, when Kreia turns out to be TheManBehindTheMan, she uses this as the player character's incentive to follow her to the final planet in the game - if they try to run or hide, Kreia will kill herself and thus also kill the PC no matter where they may be.]]

* In ''Webcomic/GirlGenius'' Martellus tries to control Agatha this way. [[spoiler:He changes her body's chemistry so that she needs to be around him to survive. If he dies so does she. Agatha gets around this by applying whatever he did to himself to a wasp eater. Although she still needs one of them near to live, she is no longer dependent solely on Martellus.]]
** Later another character suffers the same problem. [[spoiler:Turns out the chemistry alteration is a two way street and now ''[[HoistedByHisOwnPetard Marellus]]'' will die without Agatha's touch and unlike her he has ''no'' alternative.]]

* In ''Disney/{{Tangled}}'', Gothel is dependent on Rapunzel's magical hair to keep her perpetually young; without it, she will rapidly age until death.

* In ''VideoGame/XenobladeChronicles2,'' if a Driver dies, then all [[EmpathicWeapon Blades]] they've resonated with will return to their [[HeartDrive Core Crystals]], [[DeathOfPersonality never to remember their past lives upon reawakening ever again.]] If a Blade were to share a piece of their Core Crystal with their Driver [[spoiler: or if they were to infuse human cells into their being to become Flesh Eaters]], then [[FinalDeath they'll die for good.]]