->''"Luminous beings are we; not this crude matter!"''
-->-- '''Yoda''', ''Film/StarWarsTheEmpireStrikesBack''

Spiritual [[PowerSource fuel]] that runs the body and mind, generally invisible to science (but not LostTechnology). Life Energy may be the same thing as the spirit, or rather just some sort of spiritual LifeMeter. Even the [[MohsScaleOfSciFiHardness hardest]] of television ScienceFiction can't seem to help but use this trope at one point or another, even though modern science doesn't give it a leg to stand on.

Relatedly, even the hardest-nosed Nietzscheans and Randians have been known to go on (the latter at length, of course) about the "life-force".

In {{anime}}, is often the [[OurVampiresAreDifferent vampire alternative]] to [[BloodlessCarnage drinking blood]], but also is often used to explain why human blood is [[ThePowerOfBlood better]] for vampires than non-human or why they can't feed on the dead. It just sates their HorrorHunger better. Many {{anime}} antagonists, especially enemies of {{Magical Girl}}s, are [[LifeDrinker thaumovores]]: [[VampiricDraining they feed on Life Energy or use it to power their evil plans]]. A clear sign that a character is a life-force sink is the [[EnemyToAllLivingThings spontaneous death of flowers around him or (usually) her]].

The victim of Life Energy theft may recover if only a little of it is taken, or else may end up in a [[ConvenientComa coma]] that is unexplainable to mundane doctors. Other results include becoming a walking EmptyShell, or outright dying as the body becomes a skeleton or even [[NoBodyLeftBehind crumbles to ash]].

In the west, stealing Life Energy tends to be less common than giving Life Energy. Infusing someone with Life Energy (or sometimes [[PureEnergy Generic Energy]]) can be used to revive those who are critically injured, or to grant temporary superpowers. Watch out for PhlebotinumOverload, however.

It's connected to [[OurSoulsAreDifferent souls]], HermeticMagic, KiAttacks, PsychicPowers and other superpowers; see also {{Mana}}. In RolePlayingGame terms, it's the combination of Hit Points, Magic Points, and Experience. Transferring it may cause physical changes that are LiquidAssets. Occasionally, part of an EquivalentExchange to power an ArtifactOfDoom or EvilWeapon.

It should be noted that somehow many spacecrafts' [[EverythingSensor Everything Detectors]] can scan for it, and yet somehow only pick up humans or things like humans. Bugs, rats and the vast trees of [[StargateCity Canada-in-the-Pegasus-Galaxy]] do not make the grade, so obviously life signs automatically imply sentience (or at least really-bigness).

Anyone whose life energy is especially SupernaturallyDeliciousAndNutritious is in for a hard time.

Not to be confused with [[{{Gradius}} the NES space jet game of the same title]], or the 1985 sci-fi movie ''Film/{{Lifeforce}}''.

See also AuraVision and AnatomyOfTheSoul. If LifeEnergy is used to power a device, the thing powering it is a LivingBattery.
----
!!Examples

[[foldercontrol]]

[[folder:Anime & Manga]]
* Tien from ''DragonBall'' and ''Dragon Ball Z'''s signature technique uses his life energy, making it one of the most powerful techniques in the series.
** Goku's ultimate technique, the Spirit Bomb, draws in small amounts of life energy from everything around it and unleashes it in a huge explosion.
* Goes by the name ''Power of Existence'' in ''ShakuganNoShana''. Losing any amount of it turns a human into a Torch at best, doomed to eventually [[RetGone have never existed]].
* First-season ''Anime/SailorMoon'' villains, The Dark Kingdom stole life energy from humans in to free the BigBad from her [[SealedEvilInACan prison]], as did the mini-arc villains in the second season, Ail and En who feed it to the magic tree that kept them alive.
* ''KeyTheMetalIdol'' has a CorruptCorporateExecutive engage in Life Energy harvesting far more effectively than the Dark Kingdom ever did. For example, random people at rock concerts, where it's expected for there to be fainters.
* ''MagicalGirlLyricalNanoha'''s second season had the antagonists stealing magical power from mages (magical beasts when they could, though) in order to complete "the Book of Darkness." Fortunately, people can recover from that, and depending how young they are, their powers can also completely replenish.
* In ''Manga/FullmetalAlchemist'', while alchemy largely draws on natural energy, such as plate tectonics, the greatest source of energy is [[spoiler:the Philosopher's Stones which are in fact [[PoweredByAForsakenChild concentrated liquid souls]]. Ed soon realizes that if the souls of others can be used as energy, so can his own; since then he has shown the ability to transmute using his own soul to achieve normally impossible human transmutations]].
** A different twist occurs in [[Anime/FullmetalAlchemist the 2003 anime version]]. [[spoiler:Sacrificed life energy is revealed to be the actual source of all alchemic power, and it's not even people from Al and Ed's universe who are providing it]].
* ''{{Bokurano}}''. The giant robot is powered by the Life Energy of the pilot. [[spoiler:Win or lose, the pilot dies after the battle -- it just isn't followed by the ''the entire universe dying'' in case of a win.]]
** The manga even hints that the younger the person, the more life energy he/she has, and the more powerful Zearth becomes.
* The premise of ''Manga/YuYuHakusho'' implies that life energy is essentially the same as spirit energy but is the necessary portion reserved to keep the body running. It seems to be a fair amount, to the point that a person drained of spirit energy can still throw a large enough energy attack to win a battle, provided that they're okay with being dead afterwards. All but one of the four major characters are guilty of this at one point or another, and the main character employs it as a reliable backup strategy.
** Seeing that he's half-demon and can pretty much reincarnate at will, this tactic is pretty cheap.
* Michel of ''MermaidMelodyPichiPichiPitch'' steals it from powerful beings. This usually means absorbing them into himself (as he tried to do with Seira), but he left Kaito alive to blackmail Lucia with. Near the end, [[spoiler:his VillainousBreakdown propels him to kill his own followers to take their energy, even when they ''haven't'' [[YouHaveFailedMe provoked it]].]]
* Chakra in ''Manga/{{Naruto}}'' is a combination of a person's physical and spiritual energy. While it can be used to power jutsus and enhance the body, it is also required to keep the body functioning. If you use up enough that your body has less than the minimum needed for the body, you suffer from chakra exhaustion. If you use up absolutely ''all'' of it you die.
** Natural energy found in the world acts as a third component of chakra if a person is able to learn how to use it. It's present wherever there's life and greatly enhances the body, but drawing too much will overwhelm the user's own chakra and [[TakenForGranite transform them into stone]].
** Chiyo can also use life energy to heal, albeit with EquivalentExchange involved. The first time, she transfers her life energy to heal a mortally wounded Sakura, saving Sakura but bringing herself to the brink of death. The second time, [[spoiler:she brings Gaara back to life but dies in the process]].
** In a twist, it was revealed that [[spoiler:the Tailed Beasts are composed of the fragmented chakra of an EldritchAbomination defeated centuries in the past]].
*** In an even bigger twist, [[spoiler:''all'' chakra has been revealed to originate from the Ten-Tailed Beast when it existed as the God-Tree. The Beast is attempting to reclaim its stolen power and will drain a shinobi completely dry of chakra in seconds. As noted above, losing all your chakra is fatal]].
* ''Manga/{{Bleach}}'' features vampire-like creatures called Bount, which drain the lifeforce out of their victims as opposed to blood.
* ''Anime/{{Pokemon}}'' features Aura (described by Mei Ling as "life force") which is normaly used by Lucario's and, to a lesser extent, Riolu's (oh, and there's the occasional human with Aura abilities). Needless to say, an awful lot of cool powers come with it. How about unlimited vision when you've got your eyes closed, so you'll technically never go blind? Or a cool ball of energy that you can summon out of nowhere?
* Life Energy is a major theme in many ''Franchise/{{Gundam}}'' works. Various Gundams in later UC stories have Gundams powered by various bits of {{Magitek}} in all but name that run on their pilot's life energy. Used much more blatantly in the less serious ''[[Anime/MobileFighterGGundam G Gundam]]''. ''[[Anime/MobileSuitGundamWing Gundam Wing]]'' uses it less, but it does feature killer robots who can sense the life energy of their targets, even through metal, InfraredXRayCamera-style.
* The plot of ''{{Pretear}}'' pretty much revolves around Life Energy (Leafe). In the manga version, this gets downright cruel: the Knights can only use their ElementalPowers at the expense of their own Leafe; as a result, whenever Himeno is performing attacks as the Pretear, she drains the Life Energy from whichever Knight she is currently merged with. The Pretear can also ''create'' Leafe, though. Needless to say, the [[MonsterOfTheWeek monsters]] and the BigBad of the series really like ''stealing'' Leafe...
* In ''Manga/SaintSeiya'', the key to the Saints' power is their cosmos. Whoever can burn his cosmo to the higher level wins, no matter how injured or weakened they are.
* In ''Manga/KatekyoHitmanReborn'' there's Dying Will, which started out as just something that tapped into your hidden potential to keep you from dying without fulfilling some desire. Later on though, it became the basis for all forms of attack and even has [[ColorCodedForYourConvenience seven differently colored]] types with various powers and appearances, and is accessed through your personal resolution. They have a sky theme (Sky, Sun, Storm, etc).
** Now there are [[ArcNumber seven]] more flames with an Earth theme (Earth, Forest, Swamp, etc).
* In ''Manga/InuYasha,'' there are two kinds of souls: one is your true self, and one is the power that animates the body. Seeing how nobody reacts to Kikyo as a soul-stealer, she is presumably surviving on this second kind.
* ''BusouRenkin'' has the Black Kakugane, which drains all nearby life energy.
* In ''Manga/HunterXHunter'', Nen is life energy that all humans [[spoiler:and later generations of Chimera Ants after a Queen devours a pair of human children]] possess. Once a person unlocks their Nen potential their Nen manifests as a BattleAura that can only be seen by other Nen users.
[[/folder]]

[[folder:Comics]]
* This may be what the planet-eating {{Galactus}} in MarvelComics feeds on.
* The Life Entity of the GreenLanternCorps mythos is the embodiment of life, and thus, is [[EnergyBeing made of pure]] LifeEnergy.
* MarvelComics villain Selene is a mutant who can psychically drain life energy from people to sustain and empower herself. Her lifespan can be measured in millenia thanks to this power. If she ever stopped feeding for too long, [[NoImmortalInertia those millenia would catch up to her in an instant]].
[[/folder]]

[[folder: Fan Works]]
* Paul in ''Fanfic/WithStringsAttached'' has so much of this that when two wraiths feed on his life energy, ''they explode from overeating''.
[[/folder]]

[[folder:Films -- Live Action]]
* ''Film/{{Lifeforce}}'', the naked space vampire movie, is all about Life Energy vampirism. [[MsFanservice And boobies.]]
* This is essentially what one immortal gets from another in a Quickening in the ''Franchise/{{Highlander}}'' films and TV series.
* In ''Film/ScannerCopII'', it's shown that scanners possess psychic energy that can be consumed by certain other scanners, absorbing the victim's power into their own.
[[/folder]]

[[folder:Literature]]
* Creator/MercedesLackey's ''HeraldsOfValdemar'' series uses a fairly [[MagicAIsMagicA well-developed magic system]] that is based almost entirely around this concept. All living beings generate Life Energy, which drains away from them [[BackgroundMagicField into the ambient environment]], eventually collecting into {{Ley Line}}s. Where two or more Ley Lines meet, you have a [[PlaceOfPower Node]], which is a massively powerful energy source that only [[PowerLevels Adepts]] can hope to use without burning themselves out. The ultimate destination of this energy is the nether plane, from which it then reenters the world through living beings. Mages are people who have the innate capability to store additional magical energy within themselves, see this energy, and instinctively manipulate it. It's also possible to manipulate it without mage talent via rituals or BloodMagic. A person wholly drained of life energy, whether from BloodMagic or [[CastFromHitPoints spellcasting beyond their capacity]], will lapse into a coma and die. Accordingly, it can also be used to [[LiquidAssets heal people]], although this is most efficiently performed by those with the [[HealingHands specific talent]] for it.
** Lackey's ''Children of the Night'' has '[[OurVampiresAreDifferent psi-vamps]]' who drain energy from others. In this case the energy is [[EmotionEater tied to emotions]] -- they drain excitement at first, and later hate and fear. Also, a completely drained victim is usually not physically dead, but is [[TheStoic emotionally/mentally burned out]] (described as a mindless hulk, with no chance of recovery).
* The ''Literature/NightWatch'' series of novels has the "Others", a group of superpowered and supernatural humans forced to choose between good and evil when they first gain knowledge of their gift, can get energy from taking the emotions of normal humans and store it for later use. Some are actual vampires, and do need blood in addition to any life energy they get, albeit not necessarily human blood. [[spoiler: The good Others take happiness and joy, leaving those they take power from depressed and likely to kill themselves, while the evil Others take fear and depression away, leaving their victims happier and feeling more capable of dealing with problems. Although when it's not a simple one time feeding they establish a cycle where the Others create the emotions they feed off in their actions. So a famous Pioneer Camp is used as a rest resort, the Light feed during the days while helping the kids have fun, while the dark ones feed of the same kids fears at night.]]
* In the ''Franchise/HarryPotter'' universe, Dementors require (and enjoy) feeding off people's happiness, making them quite depressing to be around. (Aptly, considering they are based off of J.K. Rowling's period of clinical depression following the death of her mother.) Anyone in their immediate vicinity is prone to becoming nearly-catatonic with sadness, desperation, etc. In more extreme cases, they can give someone a "kiss" by sucking out their soul and leaving behind an EmptyShell.
** Also Tom Riddle absorbed Ginny's soul in ''[[Literature/HarryPotterAndTheChamberOfSecrets Chamber of Secrets]]'', causing him to regain physical form while she was reduced to a coma-like state.
* In Creator/LoisMcMasterBujold's ''[[Literature/{{Chalion}} Paladin of Souls]]'', this is happening to Illvin [[spoiler:to keep powering up his DeadAllAlong brother.]]
** In Bujold's ''TheSharingKnife'' books, Lakewalkers' magic is all about the manipulation of Life Energy.
* In the ''Dark Visions'' series by L. J. Smith, [[spoiler: Gabriel is a "psychic vampire", which makes him dependent on other people's life energy to survive.]]
* In Creator/HPLovecraft's short story "The Colour Out of Space", the title monster feeds on the life energy of creatures that live near to where it lairs.
* In ''Literature/TheDresdenFiles'', human beings (and other living things) have a magical essence that is necessary to sustain life, but can be fed on by White Court Vampires and some other things, and which a Wizard (or presumably even a mundane, even he somehow had the necessary skills) can tap into to power a 'Death Curse', a spell of exceptional power that can be used to spectacular things...at the cost of one's life because the energy is all used up.
** Also, in a later book, there is Soulfire. Makes your magic extremely powerful, by literally burning up your soul. [[spoiler:Good thing souls regenerate in about a week.]]
** And, in ''Literature/GhostStory'', we find that ghosts can only attack or defend by using their memories---and all a ghost is, is memories, so...
* The real threat in ''Literature/GalaxyOfFear: Ghost of the Jedi'' is that the BigBad set up the Essence Stealer which tears away and stores the life energies of [[spoiler: anyone who touches the books]]. He's aiming to get a Force-Sensitive's energy. People who've been drained can be restored if their energies are returned, but until then they appear dead and get stuck in PeopleJars.
* Literature/SimeGen, the human race has become divided into Gens who produce large amounts of life energy (called "selyn"), and Simes who don't produce it and must take it from Gens. Unfortunately the process of taking it is almost always fatal to the Gen. The plot of the series revolves around "channels" - Simes who can take selyn from Gens without hurting them in the process and pass it on to other Simes. Unfortunately, by the time the first channel is discovered Simes have been killing Gens en masse for centuries and therefore there is a lot of FantasticRacism on both sides to be overcome before the two kinds of people can finally live in peace with each other.
* In ''Literature/DeadSilver'', [[WhiteMage shamans]], like Hawke, are in tune with the life energy around them. This allows them to speak with animals and sense living things. They can also imbue objects with their own life energy, which can then [[ReviveKillsZombie seriously harm undead.]]
[[/folder]]

[[folder:Live Action TV]]
* In the KoreanDrama ''Series/MyGirlfriendIsANineTailedFox'' the titular multi-tailed fox (who has taken form as a beautiful human woman) gives a mortally injured man an "energy bead" to keep him alive.
* ''Series/BabylonFive'' has Captain Sheridan die but then get resurrected with an infusion of life energy. He was told, however, that regardless of medical procedures, his body would just "stop" after a period of time. Another plot involved an alien artifact that transferred life energy (it was used for capital punishment [[spoiler:and occasionally for medical purposes too]]).
* In ''Series/DoctorWho,'' the Fendahl consumed the full spectrum of Life Energy, causing rapid decay of the corpses it left.
** Also, "Forest of the Dead" subverts the usual rule about the EverythingSensor in regards to life forms: once the Doctor specifies that he's not interested only in ''humanoid'' life signs, the Library sensors report on ''every one of the billions of Vashda Narada spores''.
** When the Master [[CameBackWrong comes back wrong]] in "The End Of Time", the Doctor tries to warn him that his [[SuperpowerLottery awesome new powers]] are consuming his Life Energy.
* Emotions get drained in ''Series/RedDwarf'', too. A polymorph snacks on the most powerful emotion from four distinct characters. Never explored what would happen if multiple emotions got drained from the same character, but when you strip away the hero's sense of fear, you get suggestions like: "Why don't we take a nuke and strap it to my head -- I'll head-butt the monster into oblivion!"
* The Wraith in ''Series/StargateAtlantis'' are essentially [[OurVampiresAreDifferent Life Energy Vampires]]. There are, however, some {{Technobabble}} attempts to explain it as hard science, essentially implying the exact process is badly understood, and that speaking of "Life Force" is a handy though incorrect shortcut. The overall effect of Wraith "feeding", which is done through a special organ in their palm, is similar to RapidAging. They can also give back some of the stolen Life Energy, rejuvenating the subject or even bringing him back to life.
* The Lifeforce Megazord from ''Series/PowerRangersLightspeedRescue'', which uses the rangers' energy.
* ''Series/KamenRiderKiva'' features Fangires, a stained glass-based [[OurVampiresAreDifferent vampire]] race that materializes crystal fangs in midair, sticks them into their human targets' neck, and drains the life energy out of their bodies for food, leaving the victim as a glass corpse that can be shattered with a single touch. (The words Life Energy are [[GratuitousEnglish always in English]] for [[RuleOfCool some reason]].)
* In ''Series/TinMan'' [[spoiler:the Witch possessing]] Azkedellia kills at least two people with this ability and [[spoiler:murders DG as a child]] While she got better, [[spoiler:their mother had to give up most of her magic to do it, leaving her powerless later to defeat the Witch.]]
* The Dark Kingdom in ''Series/PrettyGuardianSailorMoon'' stole energy from people in various ways, just as their animated counterparts did.
* ''Tracker'' used this heavily. Each fugitive was in the form of a life force that took over a human body and killed the original occupant. Cole sucked out the life force into his collector when he caught up with them. Apparently, they were drained of life force when they were put in prison, and the life force was slowly returned as the sentence was served.
[[/folder]]

[[folder:Other Sites]]
* ''Wiki/SCPFoundation'', [[http://www.scp-wiki.net/scp-1716 SCP-1716 ("Imperfect Life Extender")]]. SCP-1716 is a device that transfers life energy from one person to another.
[[/folder]]

[[folder:Tabletop Games]]
* ''[[TabletopGame/DungeonsAndDragons Dungeons & Dragons]]'' has many creatures that can [[LevelDrain drain life energy levels]], such as many undead, succubus demons and so on. Class Levels being certainly the most hardly-earned feature of a PC, such creatures are greatly feared -- especially in 1st and 2nd edition, where such drains were permanent with no saving throw. Later editions have somewhat nerfed this power, to the regret of any [[KillerGameMaster serious GM]].
** ''{{Spelljammer}}'' also included lifejammers -- a spelljamming helm was a chair which allowed one to pilot a vessel into space by draining spell energy; a lifejamming helm ... well, you can figure it out from there. Lifejammers were particularly popular among evil beings such as neogi and undead, who were fond of subjecting their slaves and captives to this.
*** Lifejammers ''could'' be used by volunteers, since they only drain 1d8 hit points per day... a high level party could easily take this in turns and heal back up in between. Unfortunately, there's also the daily DC13 save or die; no matter what bonuses you have, someone's ''eventually'' going to roll a 1, and that's going to be bad. The manual points out that some Lifejammer captains prefer tough creatures with lots of HP, while others go the "endless supply of expendables" route.
* ''{{GURPS}} Aliens''. The Gloworms feed on LifeEnergy by touching other living creatures. They can feed on animals but prefer sentient victims.
* ''TabletopGame/CallOfCthulhu''. The Colour Out of Space monster feeds on LifeEnergy, just like the original version in the Creator/HPLovecraft story.
* ''TabletopGame/{{Alternity}}'' supplement ''Beyond Science: A Guide to FX''. The school of Necromancy is based on the manipulation of LifeEnergy in both living and dead bodies. Spells are similar to those cast by clerics/priests in ''TabletopGame/DungeonsAndDragons'', such as animating the dead, healing wounds and speaking with the dead.
[[/folder]]

[[folder:Video Games]]
* Mana from ''VideoGame/TalesOfSymphonia''. When the world decays, a Chosen sets out to restore Mana, [[spoiler:and takes it away from the parallel world, causing them to spit out a Chosen to tilt it back again.]]
* Prevalent in Nasu Kinoko's works (the {{Nasuverse}}).
** ''{{Tsukihime}}'': [[spoiler: Akiha]]'s ability ("Plunder") is taking the life energy (and heat, apparently -- there may not be much of a difference) of others through PrehensileHair that moves at the speed of thought, hits like a sucker punch or a spear, holds like a python, and is invisible even to her own eyes. Fortunately, the drain itself doesn't start or finish instantly.
** ''[[FateStayNight Fate/stay night]]'': the Mages (Masters) and their Servants have the ability to manipulate the life energy of others (mana) both willingly and [[BlackMagic unwillingly]].
* The title creatures from ''{{Metroid}}'' drain the life energy from any animal unfortunate enough to encounter it. The SpacePirates tried to use science to explain the phenomenon, but could find absolutely no trace of this "life energy", only the proof that ''something'' vital was obviously being drained.
** However, Samus's suit is able to see and absorb the life energy of defeated enemies for use as shielding or ammunition, likely due to both the suit and Metroids being created by the Chozo.
* ''Franchise/TheLegendOfZelda'' series commonly refers to Link's HP as "life energy." Whether or not this is a link to a spiritual force really hasn't been said, except if you maybe count ''VideoGame/TheLegendOfZeldaPhantomHourglass''.
** In ''VideoGame/TheLegendOfZeldaTheMinishCap'', the [[MacGuffin Light Force]] was directly tied to Princess Zelda's Life Energy. Draining away the Life Force from her body will kill her, which leads to a [[ScrappyLevel timed section]] near the end of the game. If you fail the timed section, Vaati [[NonStandardGameOver succeeds in draining all of the Light Force from her]].
* The Chromotap device in ''VideoGame/{{Syndicate}} Wars'' draws Life Energy from the recently dead to heal your agents (who probably killed them.)
* One character in the ''VideoGame/ChzoMythos'' is able to draw out the life energy of others by using a sacrificial knife.
* Raziel from the ''LegacyOfKain'' series typically feeds on the souls of the slain, but he can also snack on friendly humans. If he only drains a little, they'll get tired but eventually recover. Too much and they'll die, and then the other humans stop being so friendly.
* Life Energy was first offhandedly mentioned in the ''FireEmblem'' series in ''Genealogy of the Holy War'' under the name Aegir, but had a much bigger role as the BigBad's main power source in the seventh game, where its name was localized as "Quintessence".
* Mantra from ''VideoGame/AsurasWrath'' is this, and is also created via Human prayer. Along with powering up Technology and the Demi-gods genetically modified to use it, It also can be used in weaponry. Also played around with, in that [[spoiler: It's actually the creation of Chakravartin, The source of all mantra. Though after he dies, people still live, but Mantra is no longer around, meaning the technology powered by Mantra is LostForever.]]
* In ''VideoGame/ShinMegamiTenseiIIINocturne'', the collective life energy of the now-deceased human race is known as a substance called "magatsuhi," which flows around the [[AfterTheEnd Vortex World]] in great channels that demons flock to, trying to collect it for themselves.
* In ''VideoGame/MarioAndLuigiPartnersInTime'', it is revealed that the Toads' life energy is called vim. Without it, the Toads would wither away, and eventually die. Unsurprisingly, the villains capture a ton of Toads to suck out their vim and use it to power their ships. The poor victims are insanely close to death by the time you come across them. [[spoiler: Fortunately, seeing how one of said victims is seen alive and well during the ending, it shows that they are revived in the end.]]
* In ''VideoGame/DemonsSouls'', the level-up system, magic, and demons all make use of this. Leveling up is performed by taking the souls of fallen enemies and bringing them to the Maiden in Black, who [[YourSoulIsMine feeds them into your own]], making it stronger. Arcane magic is '''''[[SoulPoweredEngine fueled]]''''' by this, which is partly why magic is considered a dark thing at best. Demons and most of the whole conflict revolve around demons taking this from humans.
* ''VideoGame/DarkSouls'', like its predecessor, Demons Souls, has its entire level-up system revolving around this. A new type of life energy called Humanity also plays a major part, and losing it eventually turns one into a Hollow (somewhere in between TheHeartless and an EmptyShell).
[[/folder]]

[[folder:Web Original]]
* Tied into ley lines (as used by mutants like Fey) and also Ki (as used by mutants like Chaka) in the ''WhateleyUniverse''.
* In ''Literature/{{Elcenia}}'', this is the fuel used for [[MagicAIsMagicA kamai]]. Kyma can refuel with food and sleep, pretty similarly to if they had physically overexerted themselves, and they can also sense life energy.
[[/folder]]

[[folder:Web Comics]]
* [[OurVampiresAreDifferent Tristram's]] power in ''Webcomic/{{Earthsong}}'' is the draining and replacement (thereby, healing) of Life Energy.
* In ''Webcomic/{{Thunderstruck}}'', it is explained that vampires don't feed on blood per se, but on the Life Energy it carries.
* Medicine in ''Webcomic/GirlGenius'' seems to rely on "Galvanic energy," which is usually fed through big machines, or from the waters of the [[MeaningfulName Dyne]].
[[/folder]]

[[folder:Western Animation]]
* In ''WesternAnimation/AdventuresOfTheGalaxyRangers'', the Queen uses Life Energy to create psychocrystals, which power Slaverlords, wraith-like beings she can see, hear, and speak through. HumansAreSpecial in a BAD way in this universe, as they are the best species she's found to power the things. Fortunately, she only was able to make two human crystals in the entire course of the series, and only able to hold onto one. Unfortunately, that one crystal happens to be made from Zach's wife.
* In ''WesternAnimation/{{Wakfu}}'', the Life Energy is called... [[TitleDrop wakfu]]. It is the power source of all magic, and present in every living being, plants like animals. Nox, the BigBad of the first season, aims at draining as much wakfu as possible, so he can then feed it to the Eliacube, an AmplifierArtifact that can boost his powers beyond those of any time-magic user before, or even beyond those of his god, Xelor.
* The Parasite in ''WesternAnimation/SupermanTheAnimatedSeries'' is basically a male villainous {{expy}} of [[ComicBook/{{X-Men}} Rogue]]. Humans usually wind up unconscious and twitching a little. He can also gain access to their memories, and [[VoicesAreMental sound like them]]. When he does it to [[SuperEmpowering Superman, however...]]
** The Parasite is hardly an expy of Rogue, as he is far the older character; he was around in the 60s.
* ''WesternAnimation/StarTrekTheAnimatedSeries'' episode "The Lorelei Signal". The females of the second planet in the Taurean system can only survive by draining the life energy of male humanoids, which causes the males to age and die.
* Lampshaded in an episode of ''WesternAnimation/{{Futurama}}'', with the Professor repeatedly insisting that the life force is a scientific thing and completely different from a soul.
* ''JonnyQuest'' TOS episode "The Invisible Monster". The title creature can eat any kind of energy, including that found in a living body. Near the beginning it consumes both its creator Dr. Isaiah Norman and a native villager.
* ''WesternAnimation/AdventureTime'''s King Worm feeds on life energy, even referring to it as such.
* ''TransformersGeneration1'': Elita-1 can stop time with in a fifty foot radius of her position. Unfortunately this drains all her life energy and is, in most circumstances, fatal.
[[/folder]]

[[folder:Real Life]]
* [[http://en.wikipedia.org/wiki/Vitalism Vitalism]] was the belief that living creatures were fundamentally different from normal matter because they were imbued with "life energy". The fatal blow to this theory came with the chemical synthesis of urea from non-living components, demonstrating that there is no difference between a chemical created in a test tube, and one from a living organism, and that no "life energy" is necessary to create biological substances, or even life. We can now synthesize most parts of cells, and synthetic biologists are working towards (and, depending on how strict your definitions are, have succeeded in) creating a living cell purely from synthesized components.
* Starting with Franz Mesmer's "magnetic fluid", every few decades someone will propose essentially the same theory, which all fall under the label of "vitalism". After Mesmer there was Carl von Reichenbach's "odic force", then Wilhelm Reich's "orgone energy" and most recently zero-point energy and other quantum mechanical phenomena have been adopted.
* Not exactly "life energy", but scientists have proposed that one way to look for life in other planets would be to study compounds as, for example, [[http://en.wikipedia.org/wiki/Methane#Extraterrestrial_methane methane]] present on their atmospheres that ''could'' have been produced by lifeforms on that planets.
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