->''"And we forgot the taste of bread, the sound of trees, the softness of the wind. We even forgot our own name."''
-->-- '''Gollum''', ''[[Film/TheLordoftheRings The Return of the King]]''

So, it has been clarified, [[WhoWantsToLiveForever immortality ]]''[[WhoWantsToLiveForever sucks]]''. You see all your [[MayflyDecemberRomance friends and loved ones die off]], you have to constantly [[{{Masquerade}} come up with new forms of ID]], and if you don't keep abreast of mortal matters, you're going to find yourself [[TotallyRadical completely irrelevant]] in a century or two. On the plus side, you're a living witness to history. You could have been alive at the fall of the Berlin Wall, the treaty at Appomatox Court House, or even the signing of the Declaration of Independence. And you'll be able to recall that as long as you live, right?

Well, hold on a second... see, one could argue that [[MySkullRunnethOver there's only so much space the brain can hold, like a video cassette]]. Which means that, if you live long enough, your brain's going to start recording over itself. You might forget where you were born, what your parents looked like, hell, maybe even what your real name is. And it'll be lost forever to the sands of time.

[[BlessedWithSuck Sucks, doesn't it?]]

Unless, of course, the immortal character in question records everything in a diary/volume of books or something, but how often does this happen?[[note]]And how long would it take them to reread it all? What if they forgot it again before they finished?[[/note]]

A common partial aversion is to have the immortal's friends and family be the only thing they still can remember. The tragedies, the wonderful days, the good times and the bad may all blur together after a while, [[{{Tearjerker}} but they]] [[BittersweetEnding can still]] [[SugarWiki/HeartwarmingMoments remember those faces.]] In these cases, the memories of those people might be the only thing that holds the immortal together, as those memories are the one thing they can anchor their mind to, and without them they would forget who they are and who they were.

Not to be confused with ShroudedInMyth.
----
!!Examples:

[[foldercontrol]]

[[folder:Anime and Manga]]
* Killy of ''Manga/{{BLAME}}!'' is a cyborg who has existed probably as long as the strange machine world of the manga. He is so old that he has forgotten even that he is a cyborg. At least, it seems so. It's hard to tell.
** Probably exacerbated by the number of times he gets [[BoomHeadshot shot in the face]].
* The Abh touch upon this in ''LightNovel/CrestOfTheStars'' and its sequels. They live for between 200 and 250 years and their genetic engineering technology is such that they can live ''much'' longer. It's not enough to stop The Fog Of Ages setting in though, so their bodies are designed to shut down while their mental faculties are more or less intact.
* An {{immortal|ity}} from ''Anime/GhostSweeperMikami'' who has forgotten [[ImmortalityInducer the formula that made him immortal]], [[RobotGirl how he made his near invincible robot companion]], and lots of other information simply because of this trope. And no, Dr Chaos, [[PlayedForLaughs 2 + 2 does not equal 5]]...
* Invoked in some ''Manga/{{Bleach}}'' {{Fanon}} to explain why Shinigami generally don't remember their mortal lives- they measure their ages in hundreds.
* The manga ''Manga/{{Phoenix}}'' features a historical warlord who seeks to claim the blood of the eponymous bird, and with it, immortality, mainly so his empire won't fall into the hands of his incompetent sons. He decides against this when he gets a glimpse of himself in the future, practically invalid and bound to a machine that erases his memories so he has enough brain power to function.
* C.C. from ''Anime/CodeGeass'' suffers from this, [[spoiler: until Lelouch has a [[JourneyToTheCenterOfTheMind journey to the center of her mind]] and then Marianne returns all her memories.]]
* In the SamuraiDeeperKyo manga, this is the StartOfDarkness of MagnificentBastard Chinmei.
* ''Webcomic/AxisPowersHetalia'' has one in the video game ''Videogame/HetaOni'', where Italy has so many memories of the time loops he starts to forget things from his real past.
* In ''LightNovel/TheFamiliarOfZero'', Saito's trusty talking sword Derflinger has existed for over 6,000 years. He's very wise, but he has a lot of gaps in his memory.
[[/folder]]

[[folder:Comic Books]]
* An issue that explores all the back stories of the secondary characters in ''ComicBook/{{Invincible}}'' reveals that The Immortal has forgotten most of his life prior to becoming a superhero. Including being ''[[JuliusBeethovenDaVinci Abraham Lincoln]]''.
* Often (but not always) averted by VandalSavage, one of several immortals in the DCUniverse. However, he has other powers in addition to his immortality, one of which is SuperIntelligence, so his recall is superhuman anyway.
** Played straight in an early post-crisis story where he laments how much advanced medical knowledge (from forgotten civilizations he used to rule) he has lost over the ages. When a modern geneticist hesitates in assisting him with some human testing, he bellows that he has 'forgotten more than you'll ever learn!'
* Det. Christian Walker, the main character of ''{{Powers}}'', is actually an [[{{Immortality}} immortal]] who's been around since caveman days. He just doesn't remember anything before the early 20th century. His ArchNemesis[=/=]EvilCounterpart who has been around just as long, on the other hand, seems to remember most of it. However, at the final tragic confrontation between the two, Walker demands to know why the nemesis has done the things he's done, and why the two have been fighting all this time. His enemy pauses, then admits that he can't remember anymore.
* {{Wolverine}}, although some of this is due to LaserGuidedAmnesia; other explanations have been simply that he can't remember more than a lifetime of stuff he's done, or that it's an unfortunate side effect of his HealingFactor.
* This seems to be affecting the pygmies in ''ComicBook/PocketGod''. When Klik asks Teela when she made her gadgets, she says that she remembers making them, but not when. Kilk admit he's been experiencing similar memory loss as well and thinks it's a side effect of their ResurrectiveImmortality.
[[/folder]]

[[folder:Fan Works]]
* In the ''Manga/{{Bleach}}''[=/=]''LightNovel/TheFamiliarOfZero'' crossover ''[[http://www.fanfiction.net/s/7263810/1/The-Left-Hand-of-the-Death-God The Left Hand of the Death God]]'', Ichigo Kurosaki was betrayed by Soul Society and thrown into a dungeon to rot. By the time Louise inadvertently frees him by summoning him as her familiar, he doesn't remember how long he's been in there (he speculates he could have been imprisoned for decades or even centuries). He cannot remember his friends and loved ones' names, but he remembers their faces and what they were like, referring to Uryu as the Archer, Chad as the Giant, Orihime as the Healer, and Rukia as the Dancer.
* In ''Fanfic/AHero'', Homura has lived so long she cannot remember her parents.
[[/folder]]

[[folder:Films -- Animated]]
* The Atlanteans in ''Disney/AtlantisTheLostEmpire'' have forgotten much of their culture over the centuries, to the point that few of them can read their own writing.
[[/folder]]

[[folder:Films -- Live-Action]]
* Brought up in ''Film/TheManFromEarth'' - John only remembers "the ups and downs" and not all that much more outside of general details.
* Max Schreck, the vampire actor in ''Film/ShadowOfTheVampire'', suffers from this; most of the memories of his early life and his sire have faded, and throughout the film he claims to have forgotten killing members of the film crew less than a few hours after doing so. However, it's implied that Schreck isn't a "complete" vampire, given that he has continued [[AgeWithoutYouth aging despite being immortal]], and that he was never capable of siring vampires of his own.
* Louis in ''Film/InterviewWithTheVampire'' laments that he can remember the last sunrise he ever saw on the day he was turned in all its vivid detail, but can't seem to remember any sunrise before it.
* Despite being the provider of the page quote, Gollum from ''Film/TheLordOfTheRings'' is actually an aversion. Deep down he did remember his past life and his name. But during the centuries he held the One Ring, he just didn't ''care''.
[[/folder]]

[[folder:Literature]]
* [[MeaningfulName Professor Urban Chronotis]] from ''Literature/DirkGentlysHolisticDetectiveAgency'' by Creator/DouglasAdams is an [[{{Immortality}} immortal]] {{time travel}}er who is explicitly capable of remembering about as much as a normal human. He doesn't forget things in chronological order, though; he just gets very absent-minded.
* The immortal Nonmen of Bakker's ''Literature/TheSecondApocalypse'' series are afflicted with a particularly nasty version of this. A certain number of them, called Erratics, are driven insane by it and can only remember the most painful and violent moments in their lives. They become compelled to commit atrocities on the things they love in order to remember them.
* In David and Leigh Eddings' ''{{Belgariad}}'', Belgarath the Sorcerer has lived for 7000 years. He can remember sensations of his mother, but not her face. Nor does he remember exactly which God's peoples he belonged to. This has less to do with his age than the fact that his mother died when he was very young, and he was a callous youth with no interest in his village or their religious practices. Nevertheless, in his biography he skips over centuries at a time with only a vague description of what he was doing, and of what he does put down in detail his wife and daughter claim [[RashomonStyle he got a lot of it wrong]].
* ''Literature/TheMadnessSeason'' by C.S. Friedman has an [[EnergyBeings energy based species]] of creatures which are virtually immortal with this problem, and which therefore prefer to live in [[TheSymbiote symbiotic relationship with physically bound creatures]].
* Creator/RobertAHeinlein's Lazarus Long comments in ''Literature/TimeEnoughForLove'' after over two millennia of existence: "I told you my memory was playing tricks. I've used Andy Libby's hypno-encyclopedic techniques - and they're good - and also learned tier storage for memory I didn't need every day, with keying words to let a tier cascade when I did need it, like a computer, and I have had my brain washed of useless memories several times in order to clear those file drawers for new data - and still it's no good. Half the time I can't remember where I put the book I was reading the night before, then waste a morning looking for it - before I remember that that book was one I was reading a century ago."
* In the ''Literature/HarryPotter'' books, very old wizards like Dumbledore avoid this by storing important memories in an enchanted chalice called a Pensieve. Which is useful in other ways as well, such as making it possible to [[ExpositionBeam pass those memories on to other people as needed]].
* Crystal Singers in AnneMcCaffrey's series of that name have this problem, though it's brought on more by long-term exposure to Ballybran crystal than actual age. [[spoiler: Killashandra eventually finds a solution to this problem, accidentally.]]
* Age appears infinitely extendable in Creator/TerryPratchett's ''Literature/{{Strata}}'', and "memory surgery" prevents brain overload.
* In the ''Literature/{{Discworld}}'' book ''Discworld/{{Pyramids}}'', the high priest Dios prevented himself from dying by reversing time by sleeping in a pyramid, but mentions that the process doesn't preserve memory. Instead, he refers to the written history of the the kingdom as his memory. As a result, he can't escape a millenia-long StableTimeLoop. By the time it comes around again it's a surprise.
* In Kim Stanley Robinson's ''RedMarsTrilogy'', advances in medicine let people live to over 150, but their memories start showing significant deterioration.
** This is pretty much cured by a drug cocktail that apparently 'refreshes' the taker's memory, to the point where they have highly detailed recall of practically their entire lives.
* The Minotaur is still alive today in Steven Sherrill's ''The Minotaur Takes A Cigarette Break'', five thousand years later. His days in the Labyrinth are very vague to him.
* A point of ''[[{{Accelerando}} Glasshouse]]'' by Creator/CharlesStross. Immortality means that humans need to periodically erase their memories to make things more interesting. The protagonist has just done this when the book begins.
* The Struldbruggs in Creator/JonathanSwift's ''Literature/GulliversTravels'' have the opposite problem -- once they turn 100, they get a case of short-term memory loss so bad they can't even remember how the sentence they just finished began. (They don't die of old age, but they do ''[[BlessedWithSuck keep getting older]]'', so they become intensely senile.)
* Explicitly ''averted'' in Creator/StanislawLem's ''Observation on the Spot'' where ectocs have a photographic memory and can easily remember anything that happened centuries ago, with them being made of {{Nanomachines}}. But that's just another reason why [[WhoWantsToLiveForever there's just]] ''[[WhoWantsToLiveForever six]]'' [[WhoWantsToLiveForever of them left]].
* In StephenBaxter's ''[[Literature/XeeleeSequence Exultant]]'', Luru Parz is one of a group of immortals who have survived more than 20,000 years. She claims that they can remember events from throughout their lives, but no more or less clearly than a normal person. Sometimes, events may bring forth a distinct memory that hadn't been recalled in several thousand years. Even so, they must "edit" their memories, but it isn't explained how this is achieved.
* ''Literature/AFireUponTheDeep''. Peregrine Wrickwrackrum, a storyteller among the Tines (a pack of dog-like aliens who form a group mind) claims to have memories from his ancestors going back to the beginning of time, but admits that after you go beyond a few hundred years you can't tell the difference between legend and memory.
* In PoulAnderson's ''World Without Stars'', Humanity has cracked the immortality problem, so that no one dies of old age anymore. Every century or so people have to have old, unwanted, memories wiped, in order to make room for new memories.
* Many of the beings from the far future in the novella ''Starplex'' suffer from this. A species known as the Ibs suffers from a related problem--their natural cause of death by old age is that their memories began to overwrite their ''autonomic routines''. In this they are unlike most other sapients, who have problems with their cellular structure such as telomere shortening; the Ibs are noncellular. In fact, the protagonist meets [[spoiler: himself from eons in the future]], who has forgotten [[spoiler: his own middle name]].
* The eponymous character of ''The Vampire Tapestry'' loses his memory each time he passes into hibernation, and speculates that this is a defense-mechanism against this trope. [[spoiler: At the end of the book, he realizes it's more likely to be a defense against his becoming emotionally attached to the humans he has to prey upon.]]
* Oddly, this trope seems to apply to Hazel-rah in the epilogue to ''Literature/WatershipDown'', in which the venerable Chief Rabbit can't recall if the adventures attributed to him in his youth were real or not. On the one hand, said adventures couldn't have happened so long ago by human standards; on the other, Hazel is implied to have vastly outlived what's normal for wild rabbits, suggesting that his lapine brain's memory capacity has indeed reached its limit.
* Lampshaded in "Letter To a Phoenix", a short story by FredricBrown which is told by a narrator who is 180,000 years old (he ages one day per 45 years). He states he doesn't remember his own name because he only has enough place in his head for the important facts - and what could be less important than a 180,000 year old name he changed about a thousand times already?
* In Creator/AlastairReynolds's ''Literature/HouseOfSuns'', the long-lived protagonists who've lived through ''six million years'' (though, admittedly, only a couple tens of thousands of those conscious) routinely re-arrange their memory. It's implied that they ''could'' hold all of their memories at once, if they wanted to, but having that many memories would affect your personality so drastically that most choose not to. Most the long-lived characters tend to hold a rough cliff-notes version of their memories in their heads, but not any of the details; tne main character intentionally prioritizes "recent" memories, which in part drives the main plot.
* Also by Creator/AlastairReynolds, ZimaBlue focuses in part on Arthur Zima's quest to find out where his obsession with a particular shade of aquamarine comes from.
* ''Literature/TheSecretsOfTheImmortalNicholasFlamel''
** [[Literature/TheEpicOfGilgamesh Gilgamesh]] has this problem. He is the oldest immortal, the only being that is truly immortal, (Elders and other immortals can be killed in battle) and has gone insane because of it. He has tried to kill himself a few times; one attempt involved standing under the test of the first atomic bomb.
** Flamel himself suffers from this sometimes. He once forgot how to speak English.
* Khayman in ''Literature/QueenOfTheDamned'' suffers from this. As the third vampire ever in existence, he has spent the last 6000 years continuously active, alternatively losing and regaining his mind over the centuries, thus remembers little of his own life. It's been implied that during his periods of sanity, he engages in a game of manhunt with the Talamasca, who study the supernatural, while simultaneously writing many treaties on the origins of the vampire race as a ''member'' simply because [[RefugeInAudacity he likes to mess with them]].
* Vampires in ''Literature/{{Twilight}}'' have PhotographicMemory, but Alice cannot remember anything from back when she was human.
* Addressed in the ''Literature/CommonwealthSaga'' by PeterFHamilton, where rejuv (restores youth) and quick-grown clones (in the event the body actually dies) together make humans functionally immortal. Everyone has a computer core in their brain that among other things records their memories. This core is regularly backed up to a municipal database.
* In the ''TabletopGame/MagicTheGathering'' novels, Archmage Eternal Jodah deliberately inflicts a version of this on himself every hundred years or so - storing his memory in a magical mirror, wiping his brain clean, then "reloading" himself. This allows him to keep the memories without the deep emotional attachments - which would cause him to lock up mentally.
* "Shining Hawk" in TheGnarlyMan is a Neanderthaler who got zapped by lightning and wound up not aging, or at least aging very slowly. When he's interviewed, he turns out to be less useful than hoped: he can remember the broad strokes pretty well, but he gets his times mixed up ("Let's see, most of the men in the crowd had beards, so that was 8th century, or was it 12th, there were a lot of beards then too..."). Also, it turns out that unless you're invulnerable as well as immortal, the best way to survive history is not to be present during any of the more exciting bits of it, so anything interesting enough to be worth writing down he probably wasn't around for.
* In the ''{{Literature/Deverry}}'' novels, this is mentioned as a problem for elves (And the immortal human magicians Nevyn and Aderyn) as they get into their fifth century. In the days when the elves lived in cities, they tended to live extremely ritualized lives purely to help people who faced this function. Once the cities were destroyed and they became nomads, they tended not to live as long, so this ceased to be so much of a problem.
* Discussed in Creator/SergeyLukyanenko's ''Literature/LineOfDelirium''. [[TheEmperor Emperor Grey]] wonders how many memories his brain can store. He wonders if anyone ever told him and then supposes it's possible they did and he simply forgot. Since ResurrectiveImmortality is possible for the richest few percent in this world, all memories are recorded (via an implanted SubspaceAnsible) and stored in massive databanks to download into the mind of a newly-cloned body whenever the previous one dies. Grey is one of the early adopters of [=aTan=] (number 89, actually). By the time the novels take place, he is over 200 years old.
* In ''Literature/TheSagaOfTheNobleDead'', the vampire Pawl a'Seatt is so old that many of his memories have faded, and he can barely recall anything at all about his early life or how he became a vampire.
[[/folder]]

[[folder:Live Action TV]]
* In the last episode of ''Series/{{Angel}}'', the eponymous character asks Harmony if she remembers what it was like being human because he no longer remembers, himself.
** Earlier, Darla, resurrected human, realizes she no longer remembers what her name was before she became a vampire.
* Methos from ''Series/{{Highlander}}: The Series''. When he tells [=MacLeod=] that he's over 5000 years old, he explains that's when he took his first head and "before that, it all starts to blur." Methos therefore has no idea ''how much'' over 5000 years old he is; for all he knows he could've gone for thousands of years before meeting another Immortal for the first time and killing him.
* In ''Series/TheXFiles'' episode "Tithonus", a man who couldn't die because he'd "missed his chance" tells Scully he went to the records office once to look up some facts on his late wife, only he couldn't remember her name.
* Death from ''Series/{{Supernatural}}'' can't remember if he is as old as ''or older than'' {{God}}. God, apparently, doesn't know either.
* ''Series/DoctorWho''. WordOfGod has it that the Doctor can't remember how old he is anymore, instead going with the generic 900 years whenever the issue comes up.
** Now he's even older; In "The Day of the Doctor," the War Doctor and his tenth and eleventh incarnations are stuck in the same cell:
--->'''War Doctor:''' How old are you now?\\
'''Eleventh Doctor:''' I don't know... I lose track. Twelve hundred and something unless I'm lying. I can't remember if I'm lying about my age, that's how old I am.
** In the episode "World War III" it's a plot point that his memory is so crowded and cluttered he needs help to remember the species the Slitheen come from, and their WeaksauceWeakness. He does that lots of times. It can't help that he also remembers multiple timelines.
** Also explicitly mentioned in "Silence in the Library" when it takes the Doctor a while to recognize the Vashta Narada.
--->'''Tenth Doctor:''' Oh! Look at me, I'm thick! Old and thick! Head's too full of stuff, I need a bigger head!
** At least he remembers the important things. In the short "Good Night," he has this to say when Amy comments that his companions are such tiny parts of his life that he must hardly notice them:
--->'''Eleventh Doctor:''' You are enormous parts of my life. And you are all I ever remember.
** This seems to be why the Time Lords have the Matrix, which records all their knowledge.
** Earlier episodes from the original series back this up. When in regeneration psychosis, The Doctor often mentions previous companions, either for no reason or referring to his current companions by some other name. Perhaps the companions are the way he keeps track of his time: "That was when I with him, then there was a gap, and then I met ''her''."
** The Twelfth Doctor does confirm that he's over 2000 now. It's kinda hard to ignore the 900 years Eleven spent on Trenzalore, fighting off constant invasions.
* According to Seven of Nine from ''Series/StarTrekVoyager'', the Borg also suffer from this, as their memory from over 700 years ago is beginning to fragment.
* An episode of ''Curiosity'' featuring Adam Savage of ''Series/{{Mythbusters}}'' was depicted as a future autobiography he wrote at age 1000. Among the other technological interventions he'd used to prolong his lifespan, he [[BrainUploading linked his brain to a computer]] so he could use its memory banks to supplement his own overfilled storage capacity.
* Parodied on Canadian teen sitcom ''Series/MrYoung'' with Mrs. Byrne, who has a memory span of a few seconds due to having lived through an ice age.
* According to the fan favourite episode [[MusicalEpisode "Brigadoom"]], the Brunnen-G of ''{{Lexx}}'' suffered pretty heavily from this trope, after retreating behind a nigh-impregnable shield on Brunnis II and cracking the immortality problem. It's implied this contributed to their insular behaviour and eventual downfall.
* In the second episode of Urban Gothic, vampire Rex (played by Keith-Lee Castle) admits that he can't remember how he became a vampire.
* So far averted with ''Series/{{Forever}}''. Both Henry and "Adam" seem to still remember everything in their very long lives.
* [[ImpliedTrope Implied]] in ''Series/{{Alphas}}'' about Stanton Parrish, who has a form of immortality. He records all his memories using an Alpha named Mitchell (long story short, Mitchell is sort of a living journal). It's suggested that he does this because he's lived so long that he can't hold onto all of his memories.
[[/folder]]

[[folder:Tabletop Games]]
* ''TabletopGame/VampireTheRequiem'' is the TropeNamer. One side effect of torpor (the comatose state [[OurVampiresAreDifferent vampires]] experience when they run out of blood or are beaten into unconsciousness) is that, the longer the [[OurVampiresAreDifferent vampire]] sleeps, the more their memories shift. A two week nap is no big problem, but if you're asleep for decades, trying to recall your own memories is like trying to remember details from a dream. A number of bloodlines put a spin on this basic concept:
** The bloodline known as the Agonistes, introduced in ''Bloodlines: The Chosen'', who have devoted themselves to subverting the trope. Elders hire them when they prepare for torpor, and the Agonistes first record everything they can before using their special devotions to drive out as much of the fog as they can. They are ''very'' good at their jobs... and have received no end of persecution, as many vampires would prefer certain facts to be lost to the ages.
** The Usiri of ''Ancient Bloodlines'' can also protect the memories of torpid vampires. Unfortunately, their true power is in pumping the spirits of torpid vampires for anything they can learn.
** ''Immortal Sinners'', one of the Night Horrors books for Requiem, also shows the rare subversions-certain very old, very powerful vampires, called Methuselahs, have learned to cheat the Fog of Ages, meaning they remember everything they care to. The example still makes grandiose claims about who he is, but that's because he's a habitual liar and TricksterArchetype who mainly does things ForTheLulz (and his ''real'' origin story is still pretty unbelievable).
* ''TabletopGame/MummyTheCurse'' averts this: it's not time that induces the fog for a mummy, but various events that have eroded their identity. By discovering evidence of who they used to be, and recognising other people as more than a means to an end, a mummy can regain their identity and memory, until eventually at the highest levels they remember all of their many lives.
* In a ''TabletopGame/{{Warhammer 40000}}'' background story, this is shown to be a problem for some Chaos Marines (the oldest of them being over 10,000 years old). The marine uses a special mental ritual to sort through and 'store' any memories from the past year he wants to keep (it turns out the only thing he feels worth keeping is killing a Space Marine).
* The 'World on Fire' campaign setting from ''Spycraft'' has the Immortals as one faction. They succumb to this--at least, the ones who don't die from 'live fast, die old'.
* ''TabletopGame/DungeonsAndDragons''
** In the classic version, the oldest of Immortals don't recall having ever lived as mortal beings. It's implied that they simply can't ''remember'' their mortal lives; Korotiku, for example, speculates that he might have been a planar spider. Note that one of the Immortals who recalls his mortality quite clearly happens to have begun his life as a '''dinosaur''', so the ones who've forgotten must be considerably older than that.
** Some splatbooks say this also happens for Liches. A Lich may be so focused on his eternal pursuit of magical knowledge that it forgets its own mortal life. Sometimes the key to defeating one is learning its mortal name.
** In the TabletopGame/{{Eberron}} setting, the [[MechanicalLifeforms War-Forged]] are immortal constructs with souls. They must get their minds periodically wiped so that they do not go insane from an overload of memories. They can, however, vaguely recall their memories in a pinch, such that they can always make an untrained Knowledge roll for the off chance that they dig up information on a subject learned in a "previous life."
* The Sindar (elves) of Hârn suffer from an extreme form of this, to the point where they will completely forget friends after a long absence. Often an elf will remember songs and tales of events he took part in but have no memory of the actual events.
* The Soulless in ''TabletopGame/{{GURPS}} Fantasy II''. All of them have been alive for some twenty millennia, but can only clearly remember a small fraction of that, and most don't remember ''anything'' from their earliest times. They even have a name for one of the side effects of this: ''pytrakzhyjzh'' is "that uncomfortable feeling when you can tell you have some significant past history with another person, but have no idea what ''kind'' of history".
[[/folder]]

[[folder:Video Games]]
* The earliest known example of this in a video game is ''[[GloryOfHeracles Glory of Heracles III]]'', for the [[SuperNintendoEntertainmentSystem Super Famicom]], where the protagonist of the game is an immortal [[AmnesiacHero who suffers from amnesia]]. This plot element is used again in one of the sequels, ''GloryOfHeracles'' for the NintendoDS, where the protagonist is also an amnesiac immortal.
* Ellen from ''VideoGame/{{Touhou}} Project'' is an immortal witch who loses her memories blocks at a time, and so she acts as childish as she looks.
** Fairies in general, and Cirno specifically, fall into this category - as {{Anthropomorphic Personification}}s of nature, they are immortal to FromASingleCell levels for as long as their aspect of nature is powerful enough to support them. Individual fairies may well be TimeAbyss material, but because they are also permanently childish and simple-minded, they often forget everything that happened yesterday, much less a thousand years ago. Cirno, for example, can only vaguely remember the previous occurrence of the flower's odd growth from ''Phantasmagoria Of Flower View'', only after being reminded a few times, and can't remember any of the details, but is fine with it, since she doesn't care, anyway. She simply wants to do what she always does - play, fly around, and pick fights to see if she'll win. Downplayed somewhat in that she's relatively young at less then a human's lifespan, as well as more intelligent then the average fairy. Simpler fairies have absolutely no sense of self-preservation whatsoever.
** Fujiwara no Mokou, an immortal, somewhat played this trope straight. In a supplementary material for a manga, it's explained that her rivalry with another immortal that's often thought to have driven her to take the immortality elixir wasn't - she had forgotten about her by the time she was tasked to dispose of the elixir and was more interested in the prospect of, er, being immortal. Her rivalry is more out of a sense that she has something constant in her life, now.
* Used in part in ''LostOdyssey''. The main character is an amnesiac immortal who's lived for a thousand years; most of his memories are recalled through dreams as the game progresses. It's not a natural side effect of the immortality, though, but rather a case of LaserGuidedAmnesia that makes him more easy to manipulate.
** Another character in ''LostOdyssey'' does in fact keep journals; when that character experiences amnesia, the journals prove to be very helpful.
* In ''VideoGame/PlanescapeTorment'', this is implied to have happened to Ravel Puzzlewell -- she's certainly not 'all there' when you meet her. As for The Nameless One himself, he is immune to this trope: He ''does'' suffer heavily from memory loss, but it's caused by him repeatedly dying and coming back instead of from living too long.
** According to Creator/ChrisAvellone, Ravel's apparent senility actually stems from the fact that due to her nature and having all of her "branches" (including Mebbeth, Marta and Ei-Veine), she sees across many planes and time periods all at once and she sometimes has trouble distinguishing exactly where or when she is (hence some of the strange dialog--it was meant to be spoken by another one of Ravel's "selves").
-->I have forgotten more of the Art than you shall ''ever know''.
* In ''[[VideoGame/The7thSaga The 7th Saga]]'', the robot Lux was built with a finite amount of memory and as a result has forgotten who built him and why.
* This is one of the defining setting traits of ''VideoGame/IMissTheSunrise''. With virtually everyone capable of living indefinitely, no one remembers more than a small portion of their life at any one time. An incredibly powerful {{Megacorp}} has arisen to store memories that would otherwise be erased over, which can be retrieved later should they turn out to be important. (This can be problematic if you've got memories you'd rather keep said {{Megacorp}} from gaining access to.)
* In ''VideoGame/EpicBattleFantasy'' ''3'', [[EldritchAbomination Akron]] has existed for so long that he doesn't remember when or how he came into being in the first place. He can still remember some things, such as being sealed, defeated, and released countless times by different heroes throughout the ages.
* In ''Videogame/DarkSoulsII'', this is one of the symptoms of the Undead Curse. The longer a person is Undead, the more their memories and sanity fade away. Human Effigies can temporarily halt this, but it still seems inevitable.
[[/folder]]

[[folder:Web Comics]]
* Immortals in ''Webcomic/ElGoonishShive'' have this as inherent to their nature, with a slight variation. Every couple of centuries, they "die" and [[LossOfIdentity lose the vast majority of their memory]] and power. They can apparently choose the time of their death, or even postpone it indefinitely, but this has [[WithGreatPowerComesGreatInsanity exactly the result you'd expect]].
** It's actually said to be a willful decision. Living forever without any kind of reset, besides the possibility of going crazy, can be just plain old boring. As such, it's less something that happens that they can postpone, and more something they simply decide to do to avoid madness and soul-crushing boredom. They do retain their memories, but memories from past 'lives' are described as though they were being read out of a book, and as a result, probably suffer from the Fog of Ages. Finally, when immortals with huge reserves of energy and an enormous amount of power get bored... Well, it is stated that it often doesn't go well for mortals. They reset so that they don't go on a murderous rampage because they got antsy.
* According to the background info for ''Webcomic/DanAndMabsFurryAdventures'', the oldest living demon is tens of thousands of years old (a normal demon life span is 1500 years) but a side-effect of whatever forgotten process that granted her such longevity is that she cannot remember back further than 100 years before the current day.
* The Branthicor in ''Webcomic/SchlockMercenary'' [[http://www.schlockmercenary.com/2007-09-02 intentionally designed their own brains to work this way]]. Their normal brains couldn't handle becoming functionally immortal due to problems with long-term/short-term memory storage, but their new brains can... If only by intentionally 'compressing' long-term information to the point where they suffer from this trope. [[AxCrazy It beats the alternative.]]
* Jin of ''WapsiSquare'' has lived for over 80,000 years due to immortality and a GroundhogDayLoop, and, as a result, she often has difficulties remembering details from previous cycles. She often entrusts people with information to help her remember.
* A variation on ''Webcomic/{{Freefall}}'' where most of the robots have a "day memory" which starts to overwrite if they stay "awake" for too long. They must connect to a "dream machine" while they recharge in order to integrate important memories into permanent memory.
[[/folder]]

[[folder:Web Original]]
* In OrionsArm this can easily happen to [[{{Muggles}} nearbaselines]] who live more than a few hundred years. Though cybernetic and [[NanoMachines nanotech]] enhancements to memory are usually widely available, it is still rare to live longer than about 1,500 years without [[BrainUploading trans]][[AscendToAHigherPlaneOfExistence cending]].
* [[http://www.furaffinity.net/user/-three-/ Three]] (aka [[IHaveManyNames Clarion, Silver, Assistant...]]) has been jumping from universe to universe for about 30-50,000 years, give or take. She can't remember exactly how old she is. She's also forgotten what her species or homeworld was called and possibly even her original name. She does try to hold on to certain memories, particularly those of close friends, lovers, and adopted children.
[[/folder]]

[[folder:Western Animation]]
* Paradox from ''WesternAnimation/Ben10AlienForce'' is so old, he can't remember his own name, hence he adopts the moniker.
** He also had a [[BoredWithInsanity small bout of insanity]], which couldn't have helped.
*** The fact that he exists outside of linear time probably doesn't help either.
* Ice King from ''WesternAnimation/AdventureTime'' is over a thousand years old, but can't remember anything about what happened or who he was back then. This is strongly implied to be a product of the same ArtifactOfDoom that made him immortal in the first place. Particularly as he seems to be completely incapable of remembering his distant past even when he sees diary entries, both video and written, which he wrote himself.
--> ''This magic keeps me alive/ but it's making me crazy/ and I need to save you/ but who's going to save me?''
[[/folder]]

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