- Fairy Tail fanfic Alternate Tail Series: The Exceed Pantherlily is described to be around Macao and Wakaba's age spiritually. But because of his race's long life, he is actually 189 years old at the start of the series.
- Hetalia: Axis Powers fanfic Gankona, Unnachgiebig, Unità: Like in canon, all the countries are this. Germany, Italy, and Japan all look 20 despite them being 1054, 2484, and 3284 years old respectively. That, and they are also really hard to kill.
- Princess Jody from Super Milestone Wars looks ten but she's actually over 1000 years old.
- A Crown of Stars: All people Shinji and Asuka meet in the Empire of Avalon are at least several hundreds of years old, but neither of them seems older than forty. Ching is 432. Daniel, the God-Emperor of Avalon is 452,388 years old and it is due to his protection that aging is not an issue in the empire. When Asuka tells Shinji about it in chapter 40, he has a very hard time coming to terms with their longevity.Shinji: Asuka, I want to ask you a question.
Asuka: So spit it out, Third.
Shinji: Well, you said I didn't want to know.
Asuka: [thinking] Oh, that. Well, better now than some comically awkward future moment. [aloud} Try not to freak out. Ching told me yesterday that she was envious of me, for meeting you when we were so young. She said she's "waited centuries" and not been lucky enough to have met anyone that... feels for her the way you do for me.
Shinji: Centuries? How old is she?
Asuka: Four hundred thirty-two. She'll be four thirty-three in five months.
Shinji: She's four hundred thirty-two and she's a Lieutenant?
Asuka: She did say she had a few decades of practice as a psychiatrist before she joined up. But see why they don't mind years between ranks?
Shinji: And Lord Verfico is a Senior Marshal... how long would that take?
Asuka: A long damn time is my guess. Given what Ching told me next about Daniel's age, I can make a fair guess as to Lord Verfico's.
Shinji: Do I want to know? [sighing] You did warn me. Alright, hit me.
[Asuka grins, and punches him in the shoulder]
Shinji: Ow! Hey!
Asuka: Oh, dont be a baby, Third. [grinning and kissing him] You just gave me a straight line, and I had to use it. It took your mind off the strangeness of their crazy long lives, didn't it? Alright, Lord Verfico is probably at least four hundred thousand years old, given that Ching said Daniel is 452,388 years old if my math is right, which of course it is.
- Bag Enders features the Fellowship of the Ring living in early-2000s England. Technically all the characters fall under this heading, being Really Six Thousand Years Old, but the hobbits in particular are constantly mistaken for children. This gives them problems when being carded in pubs, but allows them to get away with children's fares on trains and infiltrate the Boy Scouts.
- Snowmaiden plays it for comedy, when the title character asks an elf if he's not a bit young to romance her. His response is that the question is rather whether she doesn't consider him too old, as he's roughly ten times as old as she is.
- Chaos from the Tamers Forever Series fits the tropeTakato: So you're older than the Big Bang, huh?
Chaos: Yeah, pretty much... hard to believe, huh?
Ruki: Yeah, anyone would think you'd have matured by now...
- Child of the Storm has a number, including just about every adult Asgardian. Thor, Loki and Sif are about 1500, Fandral is implied to be a few hundred years older, as is Hogun. Volstagg, meanwhile, is a fair bit older than either, making him well over 2000.
- Gravemoss is over 1500.
- Doctor Strange is over 400 years old and looks like he's in his early 40s, having looked that way since he first came on the scene in the early 17th century. Due to the fact that he's a time traveller, he's probably quite a lot older - Odin's private estimate is that he was born around the same time as Thor and Loki, and that with time travelling, he's about Odin's own age of 5000 plus. The real answer is that even Strange doesn't even know, because he stopped counting at 100,000 years old. His own private estimate is around 500,000, pushing him into the Time Abyss trope.
- Wizards of the White Council can live up to half a millennium - though Dresden, a White Council Wizard himself, remarks that this is really pushing it. They also get a bit elderly.
- Sinister hasn't aged in at least a century, and comments he makes about having travelled the Silk Road suggest he's much, much older.
- This comes up in The Man with No Name when River mentions that the Doctor is too old for her. Mal, believing himself to be about the same age, feels rather put out by this. (Funnily enough, Nathan Fillion and David Tennant are less than a month apart age-wise. Were the Doctor human and both of them the same age as their actors, Reynolds would be right on the money).
- In Fallout: Equestria - Pink Eyes, the lead character Puppysmiles is a little filly. She's also was ghoulified at the start of the Great War, and though it's been two centuries since, she's still the same hyperactive foal, only with new skills.
- In Noir Ange, a Soul Eater fanfic, Zelda Kitsune is this literally, but she looks like a 17-year old girl. There's also Yuuki and Yuuka, and all of the other Witches count as well.
- In Mass Effect: Human Revolution, Adam Jensen is actually 190 years old, though this is partially due to his augments and partially due to being cryogenically frozen for a century.
- In the Pony POV Series, the entire Dark World mane cast, as Discord made them immortal and have lived for a thousand years old. Derpy also is, due to the curse Discord put on her.
- To note, the only member of the good guy's group who isn't a thousand years old or older is Apple Pie, Applejack and Pinkie's multiple times great niece and the new Element of Laughter, and Spike's the only one who's that way naturally.
- In Cadance of Cloudsdale, Princess Cadance, actually. Not that she remembers much of it.
- Justice League of Equestria:
- Rainbow Dash/Supermare is technically a thousand years old, but due to the Timey-Wimey Ball of Kryptonian Magitek, is biologically the age she appears to be physically.
- Diana was born/created about a year before the Nightmare Moon incident, making her about a thousand years old as well. However, she is physically the same age as the Mane Six.
- For that matter, Cadance was born shortly before Diana, meaning she's just as old, but again, doesn't look that much older than the Mane Six either.
- Lelouch in Soul Chess is an unusual example. While all shinigami age slower, Lelouch doesn't age at all for almost 150 years due to a Timey-Wimey Ball sending him back roughly that far after he dies. Which makes it pretty funny when people he knew as children start looking older than him.
- Hivefled; thanks to a magical life-extending kiss from Condesce, the Grand Highblood has remained an adult in his prime since before the birth of a now-elderly troll a blood caste above him (thus with a lifespan which should be significantly longer than his).
- Given that the length of Homura's "Groundhog Day" Loop in Puella Magi Madoka Magica is fairly ambiguous, some portrayals of her veer into this. In Persephone's Waltz, Homura claims to have "lost count in the four-eighties," which would make her 74 at least. A Thousand Years gives its take in the title. All The Time in the World cuts off after one million and one, which would make her hundreds of thousands of years old. The non-canon-but-official Tamura Magica claims in a joke that Homura has aged to the point of having an unnaturally-fast perception of time, viewing a loop as being only a few days. Given that such effects are thought to be dependent on proportion, this would probably make her around fifteen times older, or 210. Word of God offhandedly suggests her to be around 26.
- To the Stars explicitly notes that Puella Magi have no need to age (a fairly common piece of fanon, based on the above). Consequently, it has characters from the original series sticking around in the 25th century.
- A Hero; Homura has gone through enough time loops to memorize every single relevant event in the city, and is old enough that she can barely even remember what she was like before accepting Kyubey's deal. The fact that Puella Magi don't age severely rattles Madoka. Then there's Dalek Sec, who takes pride in being over 250,000 years old (since, as an Intergalactic Space Nazi, that denotes many years of combat and experience).
- In The Light Never Goes Out the Mane Six are really 200 years old while they look like they're in their 30s or 40s thanks to the Elements of Harmony.
- In Song of the Serpent lamia tended to live rather long lives while not looking it, due to greatly slowed aging after they hit fifteen. According to Harry's uncle his great-great grandfather died at the age of six hundred and thirteen.
- In Sonic X: Dark Chaos, Jesus Christ (yes, that one) is still in his thirty year old body despite being two thousand years old. Most of the Angels count as this, since they're all ageless Human Aliens. Some of the non-human Angels like Tephiroth take it up to eleven - several of them are trillions of years old.
- A lesser example is Tsali the Ultimate Weapon, who is actually forty years old but in an ten-year old body. It's also justified, as he was roboticized into a combat android when he was ten.
- In A.A. Pessimal's Good Omens fic The Viennese Job, the two Immortals, demon Crowley and angel Aziraphile, are in Austria in the year 1908. Crowley's job is to befriend a struggling young artist and steer him in the wrong direction. Thirty-seven years later, in the hell of Auschwitz, Crowley is genuinely guilty at what he helped bring about and in need of the sort of drink he last had on seeing the Inquisition at the height of its powers. He helps the Angel spring a death camp survivor from what has now become Soviet captivity. Ahaseurus, the Wandering Jew (see religion asd mythology folder below), whose Jewishness means he has suffered in the death camps, but whose immortality means he has been unable to die.
- This is a Fandom-Specific Plot for Naruto crossovers. Most of the time Naruto becomes The Ageless by becoming the Juubi jinchuuriki and living to see the end of the Elemental Nations. Some examples are Shinobi of the High Seas (Naruto/One Piece crossover), True Warriors Never Die (Naruto/Bleach crossover) and Ashikabi No Shinobi (Naruto/Sekirei crossover)
- Keitaro Urashima in Ancestor is actually over 1300 years old. His original name is Taro Urashima and he's pretending to be Haruka's nephew for fun despite being her many-greats-grandfather.
- Sailor Moon: Legends of Lightstorm: Jason Shepard may appear to be an ageless human adult (and quite a handsome one, given Sailor Moon's description of him), but in Lightning Round he tells Sailor Jupiter that he's 1,073 years old. He also says that the same thing could happen to her if nothing kills her.
- Butterflied: Due to a Sith's experimentation, Xander is a few centuries older than Yoda. This, along with having the memories and skills of Raksta Lsu (who is widely considered one of the best lightsaber users in history), make Xander the greatest lightsaber master ever.
- A Long Journey Home: after a Stable Time Loop, Jasmine is something like five thousand years old.
- In Fail better, a Battlestar Galactica (2003) fanfic, Lucia is a 780 years old goddess when the story begins and looks like she's in her early 30s. When she becomes human, her new body applies to this and she starts her new life being physically 30-something.
- In Jackie Chan Adventures fanfiction The Ultimate Evil, while the age of the Demon Sorcerers was never revealed in canon, Shendu reveals that if his memory serves him right, then he and his siblings (they were all eight born around the same time) reach 1500 years in a decade or two.
- All the Loopers in The Infinite Loops eventually end up as Really Millions Of Years Old (or more), but it's most noticeable and jarring with physically immature characters like Harry Potter (who happens to be one of the Original Seven loopers and is thus "breathtakingly old" even by the standards of Loopers) and the Cutie Mark Crusaders.
- Thousand Shinji: Shinji's teacher Khenmu is over 10,000 years old. He's ageless due to being a genetically-engineered human.
- Children of an Elder God: When Ritsuko wakes up from a coma and sees Maya, she thinks that she's in her forties. Maya informs her that she's nearly six hundred years old thanks to advanced aging-slowing technology.
- Last Child of Krypton: Ra's Al Ghul's real age can't be guessed based on his physique. He vaguely looks like a middle-aged man, but in reality he's lived several centuries.I am nearly seven hundred years old. Give or take. Perhaps it is five hundred. I forget so many things, having lived so long.
- In Sorrowful and Immaculate Hearts, Diana is centuries old but looks like she's in her twenties and acts that age, or even younger when she's in the grip of her enthusiasm about discovering new things they didn't have on Themiscyra. In "Christmas in Kansas", there's a running gag about Clark's parents considering Diana one of the youngsters and her reminding them she's actually older than they are.
- Cloud Strife in Once More With Feeling still looks to be in his 20s when he's 105. Likewise, Vincent and Nanaki/Red XIII look the same as they did some eighty odd years ago. While Nanaki just comes from a long-lived race, for Cloud and Vincent it's due to the experiments performed on them.
- Most of the characters from the Blooming Moon Chronicles are this.
- The epilogue of Hecate's Orphange takes place at least a hundred years after the story itself, yet the characters do not seem to have aged.
- The Melinda Chronicles is a Highlander crossover so this predictably happens with the Immortals in the cast. Melinda herself takes this up to 11 by appearing to be around 19-20 despite being born sometime in the very early ninth century. Sonic even mistakes her for Tails older sister instead of his adopted mother when they first meet.
- In Guardians, Wizards, and Kung-Fu Fighters, Daolon Wong is eventually revealed to have been born at the end of the 15th century. Nimue and Harold Hale/King Arthur, being who they are, are over a thousand years old.
- The Bridge: Quite common between the kaiju and various magical Equestrians. Just about the only ones who look their age are Godzilla Junior, Xenilla, Mothra, Destroyah, and the Mane 6.
- Anguirus (looks 30, actually 77,000), Rodan (looks 16, actually 70,000), Queen Chrysalis and the alicorn sisters (look 25-30, actually >1,000), The Sirens (look 18-23, actually 1,000), Monster X and Gigan (look 23-27, actually 300-200), and Megalon (looks 19, actually 150).
- The Pieces Lie Where They Fell: In the sequel Picking up the Pieces, it's revealed that Cerberus, the same individual from canon, is still alive and well even a thousand years after the wedding disaster. So is Tirek - Gentle Step saw him in his cage during her trip to Tartarus prior to her promotion to Captain General.
- Many of the characters in Pokémon Mystery Dungeon: Hands Of Creation are immortal Mystics who have lived for hundreds of years.
- In Zim the Warlord: Irken Reversion, Zim casually reveals that he's 162 years old (163 following the six month Time Skip early in the story). This makes Dib especially disgusted at the budding attraction between him and Gaz (who's only 13), though Zim is quick to point out in Irken years (and comparative lifespans) he's only 16.
- A Diplomatic Visit: In chapter 2 of the sequel Diplomat at Large, it's mentioned that Queen Scolopidia is about three hundred years old, and still the equivalent of a teenager by Royal changeling standards.
Really Seven Hundred Years Old / Fan Works