Follow TV Tropes


The Fog of Ages

Go To

"And we forgot the taste of bread, the sound of trees, the softness of the wind. We even forgot our own name."

So, it has been clarified, immortality sucks. You see all your friends and loved ones die off, you have to constantly come up with new forms of ID, and if you don't keep abreast of mortal matters, you're going to find yourself 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 Appomattox 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 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.

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 

A common downplay 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, but they can still 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. In some cases, forgetting the things that aren't essential means not becoming bored of immortality.

When this happens to societies, it's Future Imperfect. When it happens to an individual during their own lifetime, the person is Shrouded in Myth. Can be part of the backstory of an Amnesiac God.


    open/close all folders 

    Anime & Manga 
  • Killy of 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.
  • Invoked in some Bleach Fanon to explain why Shinigami generally don't remember their mortal lives — they measure their ages in hundreds. In truth, most of them were never mortal to begin with — they were literally born in Soul Society, putting them on a different level than humans. Still comes up in fanfic a lot despite Word of God.
  • Call of the Night: After living for enough decades, vampires tend to forget their lives as humans. A known way to remedy this is to ingest samples of their own blood taken from those days, allowing them to refresh their own memories.
  • C.C. from Code Geass suffers from this until Lelouch has a journey to the center of her mind and then Marianne returns all her memories.
  • In Demon Slayer: Kimetsu no Yaiba, Kokushibo, the most powerful demon serving Muzan and one of the oldest demons in the setting, is one of the few demons who remembers his life as a human. However, it's been so long that he's forgotten the faces of everyone in his family, from his parents to his wife and child, with the sole exception of his twin brother Yoriichi.
  • An immortal from Ghost Sweeper Mikami who has forgotten the formula that made him immortal, how he made his near-invincible robot companion, and lots of other information simply because of this trope. And no, Dr Chaos, 2 + 2 does not equal 5...
  • In One Piece, the giant warriors Dorry and Broggy have been fighting an endless series of duels for 100 years, getting draws each time, over a disagreement they had in the past. By the present, they have long since forgotten why they fight, only keeping at it for the sake of honor.
  • 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 brainpower to function.
  • In Samurai Deeper Kyo, this is the Start of Darkness of Magnificent Bastard Chinmei.

    Comic Books 
  • The DCU:
    • In the run of Action Comics starring Deadman, a ghost called Tlaloc becomes convinced that he's a god after spending centuries trapped within a sacred pyramid. Deadman recognizes that they're the same and has to appeal to his human longings to stir Tlaloc's buried memories of his mortal life.
    • Legends of the Dead Earth: In Legion of Super-Heroes Annual #7, Wildfire can remember his exploits with the original Legion of Super-Heroes in the 30th Century after 4,500 years. However, with the passage of time, he has forgotten his real name, Drake Burroughs, and most other details of his life. The Legionnaire Membrain helps him to recover his memory through sensory deprivation.
    • The Multiversity: In Society of Super-Heroes: Conquerors of the Counter-World #1, Immortal Man notes he's forgotten his own name over the ages. It's not stated if his Evil Counterpart, Vandal Savage, has the same problem.
    • In an early Post-Crisis story, Vandal Savage 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!'
    • Wonder Woman: This is an admitted issue for Olympians and other such long lived individuals in volumes 1, 2, 3, 5 and Wonder Woman: Odyssey, with Mars/Ares and Venus/Aphrodite being mostly nonchalant about it and the fact that they have drastically changed over time and Zeus violently refusing to acknowledge it even when he's lost track of his aspects.
  • Bernadette of Death Vigil, being thousands of years old, says she doesn't remember her life before the Vigil. She remembers every single one of her friends, however, and cries after their (second) death.
  • An issue that explores all the backstories of the secondary characters in Invincible reveals that The Immortal has forgotten most of his life prior to becoming a superhero, including being Abraham Lincoln.
  • This seems to be affecting the pygmies in Pocket God. When Klik asks Teela when she made her gadgets, she says that she remembers making them, but not when. Kilk admits he's been experiencing similar memory loss as well and thinks it's a side effect of their Resurrective Immortality.
  • Det. Christian Walker, the main character of Powers, is actually an immortal who's been around since caveman days. His memory seems to stretch back only about as long as a normal human lifespan, so in the present-day of the series he can only clearly remember from about the mid-20th century to the present. He does have vague recollections of the time before that, but those memories are as undefined as an old man remembering his childhood. His Arch-Enemy/Evil Counterpart, on the other hand, seems to remember most of their history together. 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 even he can't remember anymore.
  • Comes up tragically in The Sandman (1989). The never-dying Hob Gadling is practically the poster child for Living Forever Is Awesome, but even he acknowledges that his immortality has its drawbacks. Not only does he regularly outlive his spouses and children, but after enough time passes he forgets their habits, their faces, and even their names.
  • The Transformers: More than Meets the Eye reveals that even Transformers, Mechanical Lifeforms who regularly last millions of years without slowing down, suffer from this: a phenomenon called "information creep" gradually degrades and alters their memories. In a typical example, in Overlord's memory of a gladiatorial bout, most of the crowd is the same flat color, and 1/3 to 1/4 of them are The Blank. Chromedome estimates he's 4.2 million years old based on the level of degradation. A grander example is that nobody remembers what happened to the Guiding Hand, or that they were mundane Transformers instead of mythological, supernatural gods, despite some living Transformers being their contemporaries 12 million years ago.
  • Venom 2022: Meridius, thanks to a mix of Mind Rape at his Start of Darkness and a severe dissociative disorder from everything that followed after, has blanked out on a few details. At one point Tyro, his immediately preceding persona, gets a vague flash of memory and tries reminding Meridius about it, only to be brushed off. Meridius later wonders what it was Tyro had remembered, but figures if it was important, he'd have remembered. What Tyro had remembered was that the Timey-Wimey Ball was in place, and Meridius doesn't realize Tyro was right to be concerned, moments before Meridius is pancaked by Eddie driving a time machine into him.
  • Wolverine, although some of this is due to Laser-Guided Amnesia; 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 Healing Factor.

    Fan Works 
  • The Bridge (MLP):
    • Princess Luna's earliest memory is a sweet gentle voice who may or may not be her mother. The next is of her and Celestia as children being found and raised by a foster family. This is because they don't have parents. They were newly created by Harmony when they were found, so in reality, she has No Infantile Amnesia.
    • In Monster X's heartbreaking backstory, his masters put him in cold storage until he is needed. Unable to break free, he starts repeating his name and the name of his wife and parents over and over again in an attempt to not forget but fails.
  • Played for Laughs in Fallout: Nuka Break. Ben, a ghoul, has trouble remembering things from before the bombs fell over 200 years ago. One thing that does stick in his mind, however, is "By Mennen!" Takes a much less humorous turn when it's revealed that Ben is approaching old age for a ghoul and is starting to turn feral.
  • In A Hero, Homura has lived so long she cannot remember her parents.
  • In HetaOni, Italy has so many memories of the time loops that he starts to forget things from his real past.
  • In the Bleach/The Familiar of Zero crossover 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.
  • The Lunar Guardsman: Raegdan, the lone human in the story, has fallen victim to this. He has forgotten most of his life through the rifts (as he called them it was all too similar), and many other things, including his own name as there hadn't been anyone to call him by it for so long that it's completely gone for him now.
  • In Pony POV Series, the various immortals sometimes find it hard to keep track of every little detail.
    Princess Celestia: That is only one truth Twilight, one version, and even I can't remember anymore how accurate it is. So much has been repaired and revised since then. I sometimes remember it as you've seen in that reenactment. Other times I remember it just being me and Lulu, Discord gone, and me a naive little goddess thinking that without her parents baring down on her, not there to help her, guide her, that maybe at least she could make a land where everyone was happy no matter what.

    Films — Animation 
  • The Atlanteans in Atlantis: The Lost Empire have forgotten much of their culture over the centuries, to the point that few of them can read their own writing.

    Films — Live-Action 
  • Blood of the Tribades: The vampires get this (it's even referred to as "the fog"), having great difficulty remembering things which took place long ago. Due to this, they've forgotten what their original religious doctrines were, allowing it to get corrupted over time.
  • He Never Died: Jack doesn't remember a lot of his life. He can't recall how old he is or remember his parents. Being Cain, however, he does remember murdering Abel.
  • Louis in Interview with the Vampire 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 The Lord of the Rings 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.
  • Brought up in The Man from Earth — John only remembers "the ups and downs" and not all that much more outside of general details.
  • The Old Guard: Andy is so old that she can't remember her own age, or what the members of her family looked like. Even her "real" name, Andromache the Scythian, reflects this. She was already thousands of years old by the time the Scythians entered the historical record in the 8th century BC. The Scythian era is just the furthest back she can remember.
  • Palm Springs: Niles has been stuck in a "Groundhog Day" Loop for years, possibly decades, and thus is functionally immortal. He honestly has no idea how old he is, having long since given up trying to keep track. When Sarah meets him, he's forgotten certain things about his life before the loop, such as what he did for a living.
  • Max Schreck, the vampire actor in Shadow of the Vampire, 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 aging despite being immortal, and that he was never capable of siring vampires of his own. Schreck is asked to read the novel Dracula, and later says the saddest part of the book is when this fog is lifted for Dracula when he's seen preparing a meal for his guest Jonathan Harker.
    "He has to feed him, when he himself hasn't eaten food in centuries. Can he even remember how to buy bread? How to select cheese and wine? And then he remembers the rest of it: how to prepare a meal, how to make a bed. He remembers his first glory, his armies, his retainers, and what he is reduced to."
  • Spring: Louise is about 2,000 years old. By now she can't remember her original name.

  • The Belgariad: Belgarath the Sorcerer has lived for 7,000 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 he got a lot of it wrong.
  • "The Bicentennial Man": The main character used to be an NDR-model robot, but he doesn't remember which model number. This forgetfulness was deliberate, as he could have remembered, but he was built two centuries ago and he prefers his In-Series Nickname, Andrew Martin.
  • In Camouflage by Joe Haldeman:
    • The Changeling was originally an immortal shapeshifting alien exploring the Earth several thousand years ago. However, after being separated from its vessel, it gradually forgot where the ship was and why it had come to Earth in the first place, gradually forgetting more over the centuries until it finally regressed to a near-animalistic intellect. By the start of the story, the Changeling's oldest memories concern the various sea creatures it impersonated, and it's not until it begins impersonating human beings that it finally regains its old intellect — though it takes decades before it finally remembers who it was.
    • The Chameleon is another shapeshifting immortal alien, having arrived on the same ship as the Changeling. However, unlike its counterpart, it came ashore instead of remaining at sea: as such, though it gradually forgot in much the same way as the Changeling, it retained its intellect and became regarded as a war god by the humans it lived among.
  • Captain French, or the Quest for Paradise: Averted with Captain Graham French, who has very vivid memories of his life spanning 20,000 years, although, to be fair, thanks to Time Dilation, he's only 2000 years old. He not only remembers details of his own life but recalls details of planetary histories and great literary authors. True, there are some things he's a bit foggy on but no more than an ordinary person having trouble recalling some obscure event or detail. At the same time, he mentions to his wife that the model she befriended on Barsoom has already likely forgotten her (decades have already passed for the universe outside their ship).
  • Addressed in the Commonwealth Saga: 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.
  • Wit, a recurring character in The Cosmere, is one of the oldest characters in the setting, clocking at minimum 7,000 years. The end of Rhythm of War reveals that he stores his memories in BioChromatic Breath, which is vulnerable to tampering by a sufficiently powerful being.
  • The Abh touch upon this in Crest of the Stars 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.
  • Crystal Singer: The Crystal Singers have this problem, though it's brought on more by long-term exposure to Ballybran crystal than actual age. Killashandra eventually finds a solution to this problem, accidentally.
  • In the 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.
  • Dirk Gently's Holistic Detective Agency: Professor Urban Chronotis is an immortal time traveler 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. Notably, however, when asked who he was and how he became immortal, he frankly replies he doesn't know. He has evidence he's been Regius Professor of Chronology for about two hundred years, and he thinks he took it up after he retired, but he has no idea what he retired from. What he does remember, for some reason, are earrings and smells.
  • Discworld:
    • In 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 kingdom as his memory. As a result, he can't escape a millennia-long Stable Time Loop. By the time it comes around again it's a surprise.
    • A downplayed example in the Wizards series: it's suggested a couple of times that the reason why the seventy-something Dean of Unseen University occasionally acts like a rebellious teenager is because he doesn't remember being a teenager the first time, and vaguely suspects he may have missed out on it altogether.
  • Evolution: The replicator robots share their memories with each other through the generations, but over long spans of time these become increasingly less reliable. By the time of New Pangea, the replicator swarms scattered through the stars have long forgotten where they came from, and their collective memory eventually trails away into a vague emptiness.
  • In The Familiar of Zero, 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.
  • Glasshouse: 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.
  • "Shining Hawk" in "The Gnarly Man" by L. Sprague de Camp is a Neanderthal 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.
  • Gulliver's Travels: The Struldbruggs 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 keep getting older, so they become intensely senile.)
  • Harry Potter: 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 pass those memories on to other people as needed.
  • In Heralds of Valdemar, the character Need is an ancient spirit bound into an unbreakable sword and probably is the oldest character in the setting who's not a god. Sometimes she's conscious, but she also spends decades or centuries at a stretch 'asleep', driving people to her own ends and remembering them as dreams. She shows Skif and Elspeth memories of her time in life and the moment she put herself into the sword, which they find to be so old that they're hard to understand, but she doesn't remember her living name. It seems it's still there in her memories, as she rediscovers it while sharing more with another character, she just doesn't retain conscious access to a lot of her own experiences.
  • Horseclans: After a few centuries, the Undying in many cases forget their past.
  • In House of Suns, 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 of the long-lived characters tend to hold a rough cliff-notes version of their memories in their heads, but not any of the details; the main character intentionally prioritizes "recent" memories, which in part drives the main plot.
  • Lampshaded in "Letter to a Phoenix", a short story by Fredric Brown 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?
  • Discussed in Line of Delirium. Emperor Grey wonders how many memories his brain can store. He wonders if anyone ever told him and then supposes it's possible that they did and he simply forgot. Since Resurrective Immortality is possible for the richest few percent in this world, all memories are recorded (via an implanted Subspace Ansible) 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.
  • The Madness Season has an energy-based species of creatures which are virtually immortal with this problem, and which therefore prefer to live in symbiotic relationship with physically bound creatures.
  • In the Magic: The Gathering 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.
  • Masquerade of the Red Death: Both McCann and Alicia have problems with this. More accurately, the two incredibly ancient vampires they are linked to have problems with this, and it bleeds over into their mortal avatars.
  • The Minotaur Takes a Cigarette Break: The Minotaur is still alive today, five thousand years later. His days in the Labyrinth are very vague to him.
  • In Carlton Mellick III's Neverday, most of humanity is stuck in a "Groundhog Day" Loop, making memories and knowledge the only thing that's possible to assemble. The protagonist glumly notes that actually, even that is fleeting, since while you retain your memories between each reset, they all eventually fade over time.
  • Observation On The Spot: Explicitly averted. Ectocs have a Photographic Memory and can easily remember anything that happened centuries ago, with them being made of Nanomachines. That's just another reason why there's just six of them left.
  • Khayman in Queen of the Damned 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 he likes to mess with them. Averted with his contemporary Maharet, who holds on to the memories because of her connection to the numerous descendants of her human daughter, but played straight with her twin sister Mekare, who has gone insane over the millennia.
  • Red Mars Trilogy: 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.
  • In the Rivers of London novel Lies Sleeping, Oxley, who may be the oldest of Father Thames's sons, responds to Peter's suggestion that he'd be a great history source by pointing out he only has the vaguest memories of most of his life, and certainly not of anything historically interesting that might have been happening at the time. But as long as one of his memories is the first time he met his wife Isis in the 18th century, he's content.
  • In The Saga of the Noble Dead, 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.
  • Second Apocalypse: The Nonmen accepted immortality from the Inchoroi, but did not realize that their mortal brains would not be able to handle it. Thousands of years later, they all have a certain level of amnesia. Some of their number, called Erratics, have learned that they can only lock painful memories in their minds, so they go about murdering everyone they hold dear just so they can remember that the people existed at all.
  • The Secrets of the Immortal Nicholas Flamel:
    • 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 and write English.
  • In The Ship Who..., shellpeople are Long-Lived, much more so than ordinary unshelled humans. They usually have ordinary human partners called 'brawns' who are Handy Helpers and general companions, and as ordinary humans these only stay with them for so long. Carialle, reflecting on her current brawn, wonders if she'll remember him in three or four hundred years. Losing him is a painful prospect now. After the fact, it might get more painful, and she might not even want to remember him.
  • 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 himself from eons in the future, who has forgotten his own middle name.
  • Star Trek: Immortal Coil: Ruk, an android who wasn't terribly smart to begin with, has spent 50,000 years waiting outside a bunker on Exo III. Unfortunately, he's forgotten just what he's supposed to be waiting for, and just as he's on the verge of a breakthrough, a spaceship crashes nearby.
  • Star Wars Legends: The loss of Leia's homeworld, family, and so many friends is painful decades after the destruction of Alderaan, but it's a slowly fading ache. However, it's averted in the case of her friend Winter, who remembers everything that she has learned or experienced over the years. It was said that for Winter the pain of Alderaan's destruction was a fresh wound even decades after the destruction as she remembered every detail of her home and family back on Alderaan.
  • Strata: Age appears infinitely extendable, and "memory surgery" prevents brain overload.
  • Time Enough for Love: After over two millennia of existence, Lazarus Long comments: "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."
  • The second book in the Tinker series, Wolf Who Rules, makes note that "Elves may live forever, but their memories do not." They have a special ritual they perform where they reflect on particularly important memories — good or bad — to keep them fresh through the ages.
  • Vampires in The Twilight Saga have Photographic Memory; the catch is that this only applies to memories they form after becoming vampires. Memories of their human lives are subject to fading. Alice, notably, cannot remember anything from back when she was human.
  • 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. At the end of the book, he realizes that 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 Watership Down, 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.
  • Well World: Nathan Brazil from Midnight at the Well of Souls is centuries old but only has a normal human-sized memory and has forgotten a lot of things, including his origins. When he reaches the Well of Souls, it turns out he's been there before, and the Well recognizes him and restores his old memories, including the memory of who he really is. Which he then proceeds to give several deliberately contradictory accounts of over the course of the series.
  • Averted in The World at the End of Time, as Wan-To can remember all its past life near the end of the book; its unique pastime living inside a dead star in a moribund Universe. Later, in order to leave that star corpse, must destroy most of its memories as there's no energy to carry all of them.
  • In Poul Anderson'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.
  • Xeelee Sequence: In 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.
  • "Zima Blue" by Alastair Reynolds focuses in part on Arthur Zima's quest to find out where his obsession with a particular shade of aquamarine comes from.
  • Zones of Thought: 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.

    Live-Action TV 
  • Implied in Alphas with 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.
  • Angel:
    • Darla, after being resurrected as a human, realizes she no longer knows what her name was before she became a vampire.
    • In the last episode, Angel asks Harmony if she remembers what it was like being human because he no longer remembers himself.
  • An episode of Curiosity featuring Adam Savage of MythBusters is depicted as a future autobiography he wrote at age 1000. Among the other technological interventions he'd used to prolong his lifespan, he linked his brain to a computer so he could use its memory banks to supplement his own overfilled storage capacity.
  • Doctor Who:
    • Word of God has it that the Doctor can't remember their exact age anymore — the Ninth Doctor just settled on '900' and started counting from there. This made into the actual show in "The Day of the Doctor" when the War Doctor and his tenth and eleventh incarnations are stuck in the same cell:
      War Doctor: How old are you now?
      Eleventh Doctor: Oh, 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 Three", it's a plot point that Nine's memory is so crowded and cluttered he needs help to remember the species the Slitheen come from and their Weaksauce Weakness.
    • 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 they remember the important things. In the short "Good Night", Eleven 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.
    • 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 their current companions by some other name. Perhaps the companions are how the Doctor keeps track of their 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.
    • In the Twelfth Doctor's debut episode, he's reminded of the SS Madame Du Pompadour which was seen way back in "The Girl in the Fireplace" where the Doctor met and had a love affair with the real Madame Du Pompadour and had his heart broken by it... except that now 1100 years later, he only remembers the name as something slightly familiar.
    • In "The Girl who Died", the Doctor suddenly pierces through the fog of his fading memories and remembers where he got his face from — a man whose family he once saved 1100 years ago.
    • This seems to be why the Time Lords have the Matrix, which records all their knowledge.
    • As shown in "The Woman Who Lived", the immortal Ashildr is still only a human and her brain can only store so much — after 800 years she forgets her own name, going by simply "Me". She keeps diary records about her many adventurers, which when combined take several tall bookshelves. She reads them herself now and then, to recap the events she no longer has any recollections of. She even has pages that she ripped out of some journals. She can't remember the events but does remember she ripped out the pages because the memory of the events were too painful. She does, however, keep the pages describing the deaths of her children, so that she remembers not to have any more.
    • In "Knock Knock", the Doctor encounters a woman who was made immortal 60 years ago by her father with the help of extraterrestrial termites. Things quickly don't add up when her elderly father is still alive and not affected with the same condition as her. It turns that he's actually her son who told her he was her father to explain his age because she could not retain her memory over the years.
    • In "The Snowmen", the Eleventh Doctor only barely remembers facing the Great Intelligence in his second incarnation, which was the better part of a millennium ago from his viewpoint, and in "The Giggle" the Fourteenth takes a while to recognise the Toymaker, whom he last met either thousands or billions of years ago in his own timeline.
  • Highlander:
    • Methos, the legendary Oldest Immortal, tells MacLeod that he's over 5000 years old, then 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 killing another Immortal for the first time.
    • In general, this appears to be averted for Immortals, as they have an astounding recall of events that happened centuries or millennia ago, complete with holding grudges against other Immortals they've encountered. One episode, however, had a case where two different Immortals present at the same event have very different memories of it. As the director points out in his commentary for the episode this should throw a huge shadow of doubt over all flashbacks that we see Immortals having and which had always seemed absolutely reliable before.
  • Lexx: The Musical Episode "Brigadoom" reveals that this was what happened to the Brunnen-G after retreating behind a nigh-impregnable shield on Brunnis II and cracking the immortality problem. After enough time people couldn't remember what their jobs used to be, or even which of the other immortals used to be their family members (One exchange has a pair of men wondering which one of them is the father and which is the son). It's implied this contributed to their insular behaviour and eventual downfall.
  • Parodied in Mr. Young with Mrs. Byrne, who has a memory span of a few seconds due to having lived through an ice age.
  • Star Trek: The Original Series: In "What Are Little Girls Made Of?", Ruk is an android who's spent 50,000 years on his own, and has forgotten what happened to the civilization that made him and his kind. A little prodding from Kirk gets him to remember; the androids turned on their creators in self-defense.
  • According to Seven of Nine from Star Trek: Voyager, the Borg suffer from this, as their memory from over 700 years ago is beginning to fragment.
  • Supernatural:
    • Death can't remember if he is as old as or older than God. God, apparently, doesn't know either.
    • According to Ruby, most demons have forgotten that they were once human. The only demons known to have some memory of their human lives are Ruby, Crowley, and Belphegor.
  • 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.
  • The X-Files: In the episode "Tithonus", Scully and Mulder meet a man who became immortal many years ago by accident — when the Reaper came for him, he managed to look away and the nurse at his bedside was taken instead. He spends his time tailing people he knows are about to die and taking their picture right as they're taken so maybe he can look at the Reaper and finally die himself. When Scully expresses confusion as to why he would want to die when he has infinite time to see the world and gain every piece of knowledge, he tells her that forty years ago he went to the city's public records office to try to find his dead wife's file — he couldn't remember her name.

    Tabletop Games 
  • Dungeons & Dragons
    • 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.
    • Eberron: The Warforged 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."
  • GURPS Fantasy II: The Soulless. 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".
  • Harn: The Sindar (elves) 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.
  • In Nomine: In the Angelic Player's Guide, it's mentioned that, despite being in some cases billions of years old, Celestials can only clearly recall back a few millenia at most, and often only a few centuries, with anything older then that recalled as only blurry fragements. Apparently, this is so they can interact with humans in at least a vaguely comprehensible manner.
  • Mummy: The Curse 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.
  • Spycraft: The "World on Fire" campaign setting has the Immortals as one faction. They succumb to this — at least, the ones who don't die from 'live fast, die old'.
  • Thousand Year Old Vampre: This is a major game mechanic. The vampire can only hold five Memories, each divided into three Experiences. When the vampire needs to record a sixth Memory, one of the previous five must be struck out, forgotten permanently (unless future events say otherwise). The vampire can get around this by creating a Diary, which can hold up to four Memories... but those Memories are struck from the vampire's mind, and they must trust what is written in the Diary as absolute truth, which it may very well not be. The Diary itself is treated as a Resource, which means it can be lost, stolen, or destroyed, taking its stored Memories with it.
  • Vampire: The Requiem is the Trope Namer. One side effect of torpor (the comatose state vampires experience when they run out of blood or are beaten into unconsciousness) is that, the longer the 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 The Trickster who mainly does things For the Lulz (and his real origin story is still pretty unbelievable).
  • Warhammer 40,000: 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 that he wants to keep (it turns out that the only thing he feels worth keeping is killing a Space Marine).

    Video Games 
  • In 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.
  • Dark Souls:
    • In Dark Souls II, 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. One of them, Lucatiel, begs the Bearer of the Curse to remember her name, as she's forgetting it herself. Dark Souls III reveals the Bearer kept their promise by naming a hat-and-mask set Lucatiel's Mask, which still carries her name centuries after II.
    • The Dark Souls III DLC The Ringed City has Lapp, an Undead who claims to have lived for millennia, but is so old that Purging Stones (which usually help restore fading memories) no longer work on him, and as such he cannot remember his past. He's telling the truth — as a matter of fact, he's Patches, meaning he's lived since the first game, uncountable ages ago.
  • In Epic Battle Fantasy 3, 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 the Fallout 4 DLC Far Harbor, the synth DiMA has been around since he was first created by the Institute decades ago. To help him remember more, he had his fellow synths install additional memory in him, although one of his assistants notes that the upgrades are approaching the limits of what his battery can accommodate. DiMA suggests that this is the reason his "brother" Nick Valentine doesn't remember him, since it's been a long time since they escaped the Institute and Nick hasn't had the same upgrades to his memory. Even with the memory upgrades, he's had to offload some of his memories to a computer system in an old submarine base, guarded by the Children of Atom as part of his deal with them. As it turns out, another reason's he's offloaded some of his memories is because he doesn't want to remember all the shameful, horrible things he's done to keep the peace on the Island, such as murdering the original Captain Avery and replacing her with a synth.
  • In Galaxy Angel, Moon Goddess Shatoyan has kept herself alive for over six hundred years through a complicated cloning process. As a result, she has forgotten many of the secrets of the White Moon, including its true purpose in merging with the Black Moon and the existence of the Valfask race.
  • The earliest known example of this in a video game is Glory of Heracles III, for the Super Famicom, where the protagonist of the game is an immortal who suffers from amnesia. This plot element is used again in one of the sequels, Glory of Heracles (DS), where the protagonist is also an amnesiac immortal.
  • Granblue Fantasy: By the time the crew meets Ferry, she's already a ghost. Over the decades she spent alone in her house, she slowly forgot her life from when she was alive, even her name.
  • This is one of the defining setting traits of I Miss the Sunrise. 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.)
  • The Skeleton race from Kenshi have been around for thousands of years, seeing the rise and fall of two empires before the events of the post-apocalyptic world the game takes place in. Most of the skeletons have all but forgotten their origins, and any questions about their origins and history is usually met with lack of recollection. It's rumoured in the human populations they were the cause of the apocalypse, and may be merely faking forgetfulness out of guilt or fear of being hunted down, although there are Skeletons who seem genuinely demented by their great age (such as the Armor King).
  • The main character of Lost Odyssey 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 Laser-Guided Amnesia that makes him more easy to manipulate. Another character does in fact keep journals; when that character experiences amnesia, the journals prove to be very helpful.
  • Implied in the Outer Wilds: Echoes of the Eye DLC. The inhabitants of the Stranger have been in an Artificial Afterlife for hundreds of thousands of years - they predate the Nomai, who themselves died out 280,000 years ago. As such, all the music that plays in the Stranger and the simulation has a scratchy, degraded quality to it, and the Prisoner suggests they've forgotten the Awful Truth that drove their kind to retreat into VR in the first place. You can fall victim to this too if you Earn Your Bad Ending by getting stuck in the same simulation, in which "Time passes, and passes, until your life before is some half-remembered dream. If only you could wake up."
  • In Planescape: Torment, 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 Chris Avellone, 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.
  • Touhou Project:
    • Elln 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 Personifications of nature, they are immortal to From a Single Cell levels for as long as their aspect of nature is powerful enough to support them. Individual fairies may well be Time Abyss 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 flowers' 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 than a human's lifespan, as well as more intelligent than the average fairy. Simpler fairies have absolutely no sense of self-preservation whatsoever.
    • Youkai are implied to be similar to Cirno in this regard. In a side story set during Phantasmagoria of Flower View told from Yukari's perspective, she notes that sixty years is about the farthest back she can remember for anything ordinary. Indeed, she outright states in her narration that she can only remember the most recent cycle of odd flower growth and can even feel that fading as she speaks. When explaining why the incident happens to Reimu, she genuinely feels like she'll forget if she doesn't give her explanation quickly enough. At the very least, Yukari does spend a moment pondering whether she's gone a bit senile so this may not be universally true for all youkai. Yuyuko, who also happens to be present, mentions that she can't even remember what she had for breakfast yesterday.
    • 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 actually her motive — 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.
  • In World of Warcraft Dragonflight, the player can talk with the ancient dragon Veritistrasz. He tells the player how ten thousand years ago he was close friends with a black dragon from childhood, and was even secretly in love with her. When the blacks betrayed the other flights, she murdered Veritistrasz's family and he killed her in return. Despite how tightly bound together their lives were and how clearly he remembers the events leading to her death, the thing that hurts him most is he can't remember her name.
  • Xenoblade Chronicles:
    • The pros and cons of this trope are discussed at various points in Xenoblade Chronicles 2 and its expansion Torna: The Golden Country. Pyra and Mythra, as the Aegis, hate the fact they must remember the destruction of Torna after 500 years, and at one point subtly express envy that other blades lose their memories when they "die" and are bonded with a new driver. Brighid, by contrast, keeps a diary in each of her "lives" so that she can keep the memories of her past in some form, which is made easier since she's an heirloom blade of a single royal family. And then there's Poppi, the artificial blade, who at one point suffers some minor angst when she realizes she's going to outlive most of her loved ones, but takes comfort in knowing her computer brain will never forget them.
    • In Xenoblade Chronicles 3, Triton had already been getting on in years when he first joined up with Moebius, which granted him immortality. He's a scatterbrained sort, noting that entire lifetimes practically pass him by when he blinks. He has forgotten things such as how to transform into his Moebius form, and a promise he had made to an old friend with whom he travelled to find the best recipe for the miso paste for which said friend had sacrificed his life to obtain.

  • According to the background info for Dan and Mab's Furry Adventures, 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.
  • Immortals in El Goonish Shive have this as inherent to their nature, with a slight variation. Every couple of centuries, they "die" and 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 exactly the result you'd expect. Just before they "die", they can also "record" important memories and knowledge that their next incarnation will be able to access at will, but this is compared to recalling information read from a book rather than remembering something they had personally experienced. Pandora having resisted doing so for centuries, attempted to "reset" without losing the connection to her family, but it remains to be seen how successful she was.
  • A variation in Freefall: 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.
  • The multi-millennia-old Queen Albia in Girl Genius has a secret archive of memory, since it would be impossible even for her to store them all in her head. Interestingly, the archive is partially sentient and shifts between the personalities she had during those memories. This bites her in the ass, because she had archived away an important memory from around 5,000 years prior which could have prevented the whole plot — specifically, the day her sister god-queens were slaughtered by a time-travelling Lucrezia.
    • Lucrezia herself is the same, and she wasn't terribly sane even before... whatever it was that happened to send her back 5,000 years. She has a momentary freak-out when an old college friend reminds her she used to love chocolate.
  • Kill Six Billion Demons:
    • Mammon is an immortal dragon god who holds the largest hoard of money in the multiverse. Unfortunately, his immortality has not protected him from the ravages of time; when the protagonists finally confront him, they find he's nearly blind and succumbing to dementia. He doesn't remember how or even why he collected his vast treasure and does nothing but shamble about aimlessly in his vault, counting all the gold in it. He's become such a pitiful, broken-down wreck that Allison visibly sympathizes with him, despite all the pain he inflicted on others in his youth.
    • Angels suffer a different version of this from their Resurrective Immortality. Each time an angel dies its soul crystallizes in the Void Between the Worlds until it is ready to be reborn, a process that lasts for about as long as the angel's last lifetime (as angels are The Ageless, this means a dead angel can spend a long time between lives). Each death and rebirth costs an angel about nine tenths or so of their memories and experiences, meaning that by the time an angel has died ten times any memories left of their first life is probably extremely spotty at best. Angels like 82 White Chain remember practically nothing of their origins, though their core personalty remains the same between incarnations.
  • Schlock Mercenary:
    • The Bradicor 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. It beats the alternative. Schlock himself is an evolutionary descendant of Branthicor brain material, with the same limits.
    • Then there's Eina-Afa, a super-AI in charge of a space station the size of a large planet, who has been alone for longer than humanity has existed as a species.
      Ennesby: She's forgotten more things than we currently know.
      Tagon: I've heard that one before. Old people say it all the time.
      Ennesby: Well, here's a new twist. I've seen the size of what's missing. She's forgotten more than what ALL of us know. All of us put together.
  • Jin of Wapsi Square has lived for over 80,000 years due to immortality and a "Groundhog Day" Loop, and, as a result, she often has difficulties remembering details from previous cycles. She often entrusts people with information to help her remember.

    Web Originals 
  • In The Nostalgia Critic, according to Rob, Santa Christ's age is around 2000 but he started losing his memory at 1200.
  • In Orion's Arm, this can easily happen to nearbaselines who live more than a few hundred years. Though cybernetic and nanotech enhancements to memory are usually widely available, it is still rare to live longer than about 1,500 years without transcending.
  • Three (a.k.a. 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.

    Western Animation 
  • Ice King from Adventure Time 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 Artifact of Doom 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?
  • Paradox from Ben 10: Alien Force is so old, he can't remember his own name, hence he adopts the moniker. He also had a small bout of insanity, which couldn't have helped. The fact that he exists outside of linear time probably doesn't help either. However, he does remember the details of the experiment that led to his immortality and even the name of his assistant.
  • Horde Prime of She-Ra and the Princesses of Power has lived for such a long time that he has trouble remembering it all. When he needs to recall details about a bygone era (such as the days of the First Ones), he has to access the memories of his former vessels from their preserved bodies.
  • In the Transformers multiverse, Cybertronians may be an absurdly Long-Lived race of mechanical aliens, but their recollection of their lifetime is far from perfect. They suffer a condition known as Information Creep: they gather so much information over their long lives that their brains slowly overwrite older, less important memories as they age to remain functional. Elder bots find that older events become more difficult to recall and details become less accurate as time goes on. Outside factors like mental activity, damage, and fuel levels can influence the severity of Information Creep, but it impacts them all if they live long enough. The reason their ancient history is typically lost to time despite having a few survivors of those ancient eras still around is that the memories those survivors have of their past have decayed into an unrecoverable state.
  • Dojo of Xiaolin Showdown helped Grand Master Dashi hide the Shen Gong Wu, but because he did it 1,500 years ago, he can't remember where he and Dashi put them exactly. Even if he did, the growth of civilization over all this time has rendered some of the original hiding places unrecognizable. To find them now, he has to rely on his Spider-Sense to detect the magic the emitted when a dormant Shen Gong Wu randomly activates.

    Real Life 
  • If you have a set Morning Routine, your memory of individual tasks may fall prey to this — did you feed the cat this morning, or were you just remembering doing it a few days ago?
  • The human brain can't remember everything that it experiences even within a standard lifetime. We all remember the significant moments of happiness, sadness, anger, etc. in our life and significant events, but we usually don't remember specifically where we were or what we were doing on one arbitrary day half a lifetime ago. In fact, people who do remember everything in their lives in exceptional detail are often sufferers of brain disorders or dysfunctions which affect them severely to the point where their other cognitive functions are diminished and they are rarely capable of leading normal lives without assistance.
  • Scientific evidence suggests that this may now be on its way to being an obsolete trope; evidence from the beginning of 2016 by the Salk Institute suggests that human memory capacity may be much bigger than we thought. Like size of the Internet big. And that's just the gross amount of data our brain can store, by the way. It doesn't account for any the brain's methods of data compression — which are impressive in their own right, seeing how trivially we take trains of thoughts that would fry top-of-the-line computers and compress them into simple sentences. This could mean that people don't forget standard things on arbitrary days because their brain is unable to remember them, but rather that the brain considers those things not important enough to bother keeping. It could be a question of priority rather than capability.