Immortality Begins at Twenty
"Despite what the math says, elves do not gestate for an entire decade."
Sometimes being immortal or a member of a really long lived race means that you also have an eternal
or really extended childhood or puberty. And that would really suck
On the other hand, sometimes fate can actually be merciful and aging occurs naturally or rapidly until a character physically reaches his or her mid-twenties, at which point their aging stops and they get to be young and beautiful forever, or at least a very long time. Sometimes this is explained as the character being immune specifically to the degenerative effects of ageing (sometimes as a side-effect of a Healing Factor
) while growing
isn't affected; other times they acquired their powers at a late stage of puberty
This seems to be a common feature for elves
, even if they aren't technically immortal and just long-lived. A character that's Younger than They Look
may fall under this if they weren't artificially created; sometimes a character looks like a teen or young adult but is only chronologically in the single-digits of age.
Averted with certain types of Undead Child
. See also Who Wants to Live Forever?
. Contrast Elderly Immortal
, Really 700 Years Old
. When this fails, you can have either Age Without Youth
or Not Growing Up Sucks
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Anime and Manga
- Vash and Knives from Trigun aged rapidly from birth (by the time they were a year old they were physically around 8), until they reached the physical age of men in their early twenties. Nearly a century and a half later and they haven't aged a day since.
- The Phoenix Saga of Ranma ½ has both versions of this. Usually the bird takes a hundred years to grow up, but if you force feed it enough it'll mature faster.
- The titular half-youma warriors of Claymore are probably an example of this, the key word being probably. While the few Claymores who do survive beyond the average human's prime don't show any signs of aging, most aren't likely to live even that long thanks to the dangers of their chosen profession.
- Neo Queen Serenity of Sailor Moon stops aging at 22 (as do the rest of her supernatural friends).
- Blood+: Chiropteran queens age normally like humans from birth, only for their aging to stop as soon as they turn sixteen.
- Deliberately used in Baccano! by Sylvie, who decided if she was going to stop time, she wouldn't do it as an adolescent so her appearance would change enough that her lover's murderer (also immortal) wouldn't recognize her when she came seeking revenge. She waited until she was twenty-something before taking the elixir. Averted with the rest of them, who are whatever age they happened to be when they encountered the Grand Panacea.
- Played with in Hellsing. Alucard was in his mid-forties when he died (just like the Real Life Dracula), but has the appearance of a man in his twenties because he is powerful enough to assume pretty much any form he wants. When his full power is unlocked, he resumes his original appearance (complete with mustache), but quickly resumes his usual form (and later the form of a fourteen-year old girl). The artificial vampirization process used by Millenium also restores their soldiers to a youthful state most notably with Walter. Played straight with Seras.
- Crest of the Stars has the Abh. Barring accident or illness they live to between 200 to 250 years. From birth to 15 they age at more or less the same rate as a normal human. From 15 to 25 years their maturation slows until they're at a point somewhat equivalent to a lander at age 20 at which point they only age very, very slowly.
- New Cutey Honey takes place about a hundred years after the original series, but Honey only looks a few years older . . . of course, given that she's an android, the fact that she's aged at all is surprising. Possibly justified in that she's a shapeshifter, and may have used her powers to age until her teen years were behind her.
- In Axis Powers Hetalia it is shown that the Nation-tans age as children, but are usually stuck at 20 or so. It shows Italy as a chibi in the age of the Holy Roman Empire, but adult by World War I. It helps that a nation's age progression displays their development as countries.
- Most of the shinigami in Bleach are centuries old, and yet look like they're teenagers or middle-aged. The only one who actually looks old (white beard, wrinkles, etc) founded the academy that trains them- meaning he's been alive for at least a thousand years. It doesn't help that people can apparently die, get sick, or be born into the realm of the dead.
- While not immortal, Mazoku in Kyou Kara Maou age much slower than humans. This is tragically deconstructed at the end of episode 47.
- Wolfram, who looks like a 15-17 year old Bishounen physically, is actually 82.
- Although Witches in Soul Eater live for hundreds of years, the few young witches we've seen (Angela and Kim) are by all indications the same age as they appear to be, implying witches grow to adulthood as fast a humans then grow elderly extremely slowly.
- The viltrumite Nolan Grayson aka Omni-Man and his son Mark aka Invincible from the eponymous comic book.
- Mark's half-brother, Oliver, may fit this trope even more, since his mother's race have exceptionally short life-spans, causing Oliver to age rapidly into a teenager in less than one Earth year, at which point his Viltrumite heritage kicks in and slows his aging process to a crawl.
- Jenny Sparks from The Authority stopped aging at 19 and remained that way for the remainder of the 20th century. Probably applies to some of the other "century babies" too but some of them at least appear older.
- Wolverine of the X-Men aged normally until sometime during his prime, when his aging slowed down significantly. Stories set a couple hundred years in the future often show him looking like a normal person would at 50 or 60..
- The rather obscure ClanDestine of Marvel has this in spades. It's not true immortality, as some of them age - just very slowly. The clan patriarch hasn't aged a day since the 12th century.
- The comics have gone back and forth on whether Kryptonians are immortal but no matter how slowly they age in adulthood, they always age normally up to about their mid twenties to early thirties.
- Played with in the film In Time. People are genetically engineered to stop aging at age 25, and continue to look the same until their time - which has become the new currency - runs out and they drop dead on the spot. At one point, Vincent Kartheiser's character introduces his wife, daughter and mother-in-law, all of whom look around the same age. It's also possible to kill yourself through, say, alcohol poisoning even if you still have years left.
- Star Trek: Insurrection The magic radiation produced by the planet's rings takes some time to stop/slow the aging process. So when Picard asks a young boy if he's really 75 he's told "no, I'm twelve."
- Justified In Kieli. The Undying are immortal soldiers made out of the corpses of dead ones. There weren't a lot of kids fighting in the war (which doesn't mean that they weren't dying in it), and a fully grown healthy adult is going to make a stronger, stabler, more efficient, soldier than a child. Usually.
- Subverted in Ian Mc Donald's River of Gods - one of the many enhancements given to the so-called "Brahman Babies" is a doubled lifespan. They age half as fast physically, but mentally (or at least legally) grow up at a more-or-less normal pace, leading to apparently ten-year-old night-club owners.
- A short story set in the same universe points out the rather nasty effect this has on marriages.
- Dragaera definitely uses this- from what I can tell, Dragaerans are in puberty/teenage from about ages 1-70 but then can be in their twenties or at least the prime of life for a couple of centuries and even to millennia. Unlike some elves though, they do get old eventually.
- In J. R. R. Tolkien's Middle-earth (Lord of the Rings, etc), even the long-lived human peoples are physically mature by their twenties. The immortal elves (according to a posthumously published text and thus of uncertain canonicity) reach adulthood in their sixties, but in their first years develop faster (e.g. verbal and motor functions) than their human counterpart.
- In Percy Jackson and the Olympians when a girl joins the hunters of Artemis they gain immortality,once they join they no longer age. All of the hunters are said to look in their late adolescent and teen years. Artemis says she could appear as anything she wants but she prefers appear the same age as her hunters
- The Lost Road
- On the other hand, in The Lost Road, the long-lived Númenóreans age more slowly and have an adolescent appearance and mentality when they are chronologically in their forties.
- If you look into the appendix at the end of Return Of The King, it's stated that elves have much longer childhoods than humans, and hence an elven child may have the mental capacity of a human adult. Apparently it's all relative, in any case, because if you go back to the dwelling of the Valar in Valinor, and the arrival of the three primary elf races, the perspective on growth was very different, due to immortality/longevity being the standard state of being. And so, in effect, the aging process of humans and the races of middle-earth would have been seen as abnormal by the Maiar, Valar, and elven races. However, the overriding description of elves by Tolkien isn't so much that they look like they're in their early twenties, but that they assume an ageless quality over time. The idea is that there is no human comparison for such a state because they are an alien race to the concept of mortality (if elves die on the mortal plane, they find their way back to Mandos' halls, and (usually) end up living in Valinor).
- Also averted with Hobbits, who routinely live to 100 but mature more slowly in proportion, being considered to reach adulthood at 33. Their twenties or "tweens" are considered equivalent to Men's adolescent teens.
- In the Kiesha'ra series by Amelia Atwater-Rhodes, shapeshifters age like humans and then stop aging past 20.
- Played straight in Duumvirate, where it's referred to as "maximum age".
- A science fiction story called Start The Clock (available on Escape Pod, IIRC) was all about the results of averting this trope. An ill-defined plague stopped everybody aging (and apparently gave immortality as a side-effect). The worst-hit group seem to be the teenagers, since their hormone overproduction didn't stop, turning most into what amounts to bunch of sex-mad orcs.
- In Twilight Renesmee the human/vampire will supposedly grow to be 17 in about seven years and then be immortal.
- And according to Word of God if you become a vampire while pregnant, you remain pregnant for all eternity. Or however long you manage to live.
- The dragons in Inheritance Cycle grow up within a few years, despite having very long lifespans. This is taken to the logical extreme in film, where Saphira transforms from an infant to adult in a literal second.
- Dragons reach maturity at around six months, when they're able to breathe fire, but they never stop actually growing. The largest dragons can dwarf an aircraft carrier, and they end up sleeping most of the time and living in their dreams in order to preserve their energy.
- Dragon Riders age considerably slower, but the exact details and rules around are very nebulous. Oromis lived for several hundred years and while he looks old, he doesn't have any normal signs of aging, e.g. wrinkles. Meanwhile, Brom and Galbatorix have been around for roughly the same amount of time - over a century - and lost their dragons, but Brom looks like a regular old man and Galbatorix looks to be in his 40s. Normal elves, meanwhile, also age very slowly due to their race's magical binding to dragons, and can live for hundreds, if not thousands of years without aging. The one exception might be Rhunon, but she is old even by their standards; old enough to know about life before the Riders, and bending over a forge for several thousand years can give you a bad posture.
- Partially used in The Belgariad by David Eddings. The female sorcerers (Polgara and Poledra) apparently stop aging after reaching adulthood, but the male sorcerers all appear as old men. While never stated or hinted at, it is possible that this is actually a conscious decision, as all sorcerers are also capable of shapeshifting.
- Pretty much outright stated. In Belgarath the Sorceror, Belgarath says that old men are regarded as wise sages while old women are regarded as ugly crones. It's a subconscious decision, but each sorcerer does decide when to stop aging.
- The dryads also play this straight. Ce'Nedra doesn't look to be much younger than her cousins. She's initially in her mid-teens, and looks it; they're Really 700 Years Old.
- Done in The Company Novels, where the immortals go through the immortality process from pretty much birth to age 18 and then stop aging. They have to use makeup in order to look like they are still doing so.
- In the Mercy Thompson books, all werewolves look to be in their early or mid-twenties, no matter old they were when they were turned. The only naturally born werewolf stopped aging in his mid-twenties, as well. This is stated to be part of their healing and disease resistance magic.
- Played straight in The Guardians of Time Trilogy.
- In Joanna Bertin's Dragonlords trilogy, Dragonlords are humans born among humans but utterly sterile, birth marked, and with half-dragon souls; at some point these dragon souls manifest and the Dragonlord is stronger and more magical than most humans as well as able to transform into a dragon, and from that point on they age incredibly slowly. Typically they manifest in the twenties or thirties. In The Last Dragonlord, the Dragonlord mentioned in the title is also called "Little One" because he's the youngest, at six hundred years old. Their leader manifested unusually young, at sixteen, and by this point is visibly old. The little one wonders about just how long she's been alive but doesn't ask.
- Conrad Nomikos, the main character of This Immortal by Roger Zelazny (if the title didn't tip you off, you haven't read enough of this website) looks 23. He's looked 23 for hundreds of years.
- In J.R. Ward's "Black Dagger Brotherhood" series, vampires live for hundreds of years. Their transition from "pre-trans" to full vampire occurs at about 25, and they age very slowly after that.
- Both Played Straight and Subverted in Trudi Canavan's The Age of the Five trilogy: whilst the White and the Voices stop aging when they are 'chosen' by their respective gods, The Wilds (powerful sorcerers who develop immortality naturally) generally cease to age at the point when they discover the secret. Whilst most of the Wilds are older than twenty when this happens, due to the full emergence of their powers generally happening after puberty, one of the Wilds The Gull, who is the oldest surviving immortal, is several thousand years old, but has the body of a child of seven or eight.
- In The Wheel of Time Aes Sedai use an Oath Rod (originally produced as a Restraining Bolt for criminal mages) as part of their Initiation Ceremony. As a side effect, it makes them "ageless," which means "attractive." Oh, and it cuts their lifespans in half, which they don't know until they meet wrinkled mages who are 400 years old.
- Fans who have way too much time on their hands have deduced (Based on in-book descriptions of the oath process and of the Aes Sedai themselves) that the cause for the "ageless" appearance is that, in addition to aging more slowly, they never get wrinkles (They explicitly compared this to botox).
- Inverted in Sean Mc Mullen's ''Voyage of the Shadowmoon", wherein Laron is a perpetually 14-year-old vampyre. With acne and a stuck-on beard. It sucks.
- Inverted in The Meq. The Meq attain immortality at 12 and lose it when they are ready to mate.
- In Kim Harrison's The Hollows it is implied that witches grow up like humans and age little for about a century after they reach their twenties, resulting in a natural life span of about 160.
- In Honor Harrington, prolong recipients are "frozen" at a different age range depending on which version of the treatment they got: mid-forties for 1st, late 20s for second, and early 20s for 3rd. The freeze extends lifespan to the two to three century mark. It also has the effect of extending stages of development; Honor Harrington herself was a bit of an awkward adolescent, gangly and horse-faced, until at least well into her 30's. Such treatments are new enough during the period when most published stories are set that we don't actually get to see any characters who are 250 years old but look "only" 65 or so, but first- and second-generation recipients of the Prolong treatments do seem to get a prolonged middle age as well as the usual prolonged young adulthood.
- In "Echoes of Honor" we find out that it also extends non-visible aspects of those same periods. Honor's mother, a second-generation prolong recipient, is about 100 years old but has the body of a woman in her thirties... complete with the ability to still bear children. In the wake of Honor's "death", this is exploited to resolve the issue of succession in Harrington Steading, by having her parents produce a sibling for her.
- This was subject to a retcon mid-way through the series. In earlier books, Prolong prolonged all stages of development, so that a bridge crewed by 20-something graduates of the naval academy looked more like a middle school class, which characters from worlds without prolong found disturbing. Later, however, it's said that children receive additional treatments so they develop up to their 20s at a more normal rate.
- Joan of Arc in The Secrets of the Immortal Nicholas Flamel was turned immortal when she was a teenager, so she has this. Averted with many other immortals, though.
- Discussed at one point, when somebody points out that the still adolescent protagonist may want to hold off on acquiring immortality until they were at a more mature age, since otherwise they would be a child forever.
- Played for Laughs in Guards! Guards!, when it's mentioned that dwarfs live up to around 300 and only hit puberty around 55. The human Carrot's adopted dwarf parents find it hard to cope when he reaches young adulthood at what, to dwarfs, is "playgroup age".
- Justified in Dirge for Prester John. People take their third pilgrimage to the Fountain of Youth at thirty, freezing them in time at that age.
- In Mikhail Akhmanov and Christopher Gilmore's novel Captain French, or the Quest for Paradise, the Cell Regeneration treatment, which stops the aging process in its tracks, is performed upon request. Most people tend to do it in their early 20s, although some choose to wait until they're 30 to give themselves a more "mature" look. Since the treatment is not genetic, it doesn't affect children born of CR-treated people. The treatment is reversible, but this is only done to criminals sentenced to Aging. Interestingly, youthful looks are a moot point in the novel, as "biosculpting" has allowed people to "mold" their features to any they wish. This has resulted in worlds filled with women who look roughly the same (with main differences being hair and eye colors). The titular protagonist's choice of his next wife is partly guided by the fact that he finds a stunning beauty who doesn't look like she's been biosculpted.
- In Philip Jose Farmer's Riverworld, the entire human race through history over the age of 5 is resurrected on an alien planet at the same time. Everyone is at age 20, and those who were chronologically younger than 20 continue to develop until stopping at 20. There's even a term for them "Rivertads".
- In Jack Blank, Revile the Undying has an age spanning millenia, but underneath his mask is only the face of a teenager. He was taken in by the Rüstov at that age and had undergone a radical reformation to transform him into a Super Soldier that could regenerate From a Single Cell, so he hasn't changed at all in all those years.
- This is the case with warlocks in the Mortal Instruments series. As half-human/half-demons, they age more or less normally until they reach adult, and then their aging just stops.
Live Action TV
- Buffy the Vampire Slayer:
- Angel is over two hundred years old. However, he was conveniently sired at age 26, making him seem "college" age to a layman.
- By the fifth season of Angel, actor, David Boreanaz had changed quite a lot, not just in terms of age of also physical build. He's a pretty burly guy; no longer the lithe pretty boy that he was in 1997. At the time, the disconnect between character and actor was not huge, but only would have grown larger with time.
- Inverted in an episode of Moonlight where a vampire who was turned as a young adult has to spend the rest of his immortal life in the midst of puberty.
- Adam Monroe in Heroes
- Also Claire.
- Adam says in the webcomic that he stop actually ageing (at least, he noticed it) when he was about 40. His ageing had probably slowed down before this.
- For Sylar, though, it's justified- he acquired his powers of unaging-ness when he (or the actor playing him) was in his twenties, so it makes sense that that's the age he'd stick at.
- Stargate has this to an extent with the Ancients. While they (presumably) grow up at a normal rate compared with regular old humans, once they reach maturity they seem to be capable of staying this way for a very, very long time (millions of years if they happen to be encased in ice, as was seen in one episode... though there was limited degeneration, the Ancient in question was still perfectly able to walk, think, and understand modern humans).
- Highlander: The Series both averts and explains this. Immortals are always frozen at the age when they died, so you can get child immortals, but because immortals also tend to hunt each other down, the children don't last long, so you don't see many... the ones that survive the first few years... tend to be off. Immortals above the biological age of forty also tend to be rare, for pretty much the same reason - those that aren't 'lucky' enough to start being immortal when in their physical prime (20s and 30s) are less likely to last long when other immortals come around with a sword and try to cut their heads off.
- Interestingly, the novelization of the original film appears to indicate this trope originally being played even straighter, with the immortality simply kicking in at a certain age and aging stopping. However, that never made it into onscreen canon of the film. It's possible the book was created from an earlier script, before stuff had to be cut for time or whatever.
- In Young Dracula, vampires age normally until they turn 16 years old. From the looks of Dracula, they probably still age a bit after that, but not much.
- Becoming Human averts this. Adam was turned at 16 and is stuck as either a schoolkid or someone in a badly-paid school-leaver job forever, since he'll never be able to pass for much older.
- In Kamen Rider Double, Philip died at age five and then was resurrected as a stream of data composed from the memories of the Earth. Towards the end of the show, he's confirmed to be seventeen years old, but Delusion Diary #11 hints that he won't age beyond that because his body is made of data. It may or may not be true given that the scene was part of Shotaro's daydream.
- In Kamen Rider Blade, Hajime is an Undead who lives as a human and thus will never age past his current appearance of early 20s. Highlighted in a spin-off novel where Amane (introduced in the show as a ten-year-old girl) dies as an old woman, with an unchanged Hajime by her side.
- In Can You Live Forever?, Adam finally achieves this after a long series of experimental medical procedures using Sufficiently Advanced Technology.
- In the Star Trek: The Original Series episode "Plato's Children", an alien race that based itself on Ancient Greece genetically engineered themselves to stop aging at about 30-40 years old. (When Spock informs one of the female aliens that she looks a few years older than the age at which she officially stopped aging, she's a bit miffed, despite being thousands of years older.)
- On The Almighty Johnsons the human reincarnations of the gods receive their powers on their 21st birthday. Olaf is the god of rebirth so he is 'reborn' each morning and thus is stuck at 21 and never ages.
- Religious example: Mormons (and probably other denominations believing in a physical resurrection at the Last Judgment) believe that the dead will be restored to appear as they did/would have in the prime of their lives.
- Catholics believe the same, for the blessed.
- In Hinduism, "the age of the gods is always sixteen."
- In Islam, those who enter paradise will be 33 years old eternally.
- In the Fourth Edition of Dungeons & Dragons, races that have lifespans greater than that of a human (for example, eladrin) follow this trope, maturing normally until around the age of twenty and staying like that for the majority of their lifespans. Previous editions gave the age at which they reached "adulthood" but no indication of the rate of maturity (which led to questions like, "is a one-hundred-and-ten-year old elf as emotionally mature as a fifteen-year old human?" and "is it wrong to bang an eighty-year old elf?")
- At least a few sources suggested that elven infants mature fast enough that elves probably aren't in diapers for twenty years, The Order of the Stick not withstanding.
- Adverted hard for half dragons (in some version) who may not have left adolescence by the time others have died of old age. This is in line with dragon aging where 101 years is considered adult, even considering the half part that's adulthood at 50 ish.
- In GURPS each level of Extended Lifespan doubles the amount of time spent maturing. However, Fast Maturation is available as a zero point ability with each level cutting time to mature by half causing the character to spend that much more time at their prime.
- In Exalted, Exalts (who may live anywhere from a few centuries to a few millenia, or even eternally depending on type) stop visibly aging until the very end of their extraordinarily long lifetimes. Since the average age of exaltation ranges from late teens to mid-thirties (there are exceptions of course. The youngest exalt was a preteen and still is after 1500ish years, while one of the oldest to exalt was over 60), they somewhat fit within this trope.
- Also, the Terrestrial Exalted age more continuously and gradually over the centuries (or else their Exaltations would leave a good number of them as semi-eternal children), but do not move past their (physical) fifties or so until their lifespan draws close to an end.
- Strangely enforced for Infernal Exalted; part of the deal is having vitality restored, so the general body warping process of the chrysalis grotesque includes being brought back to a physical appearance that roughly resembles their twenties (ironically, the Infernals are, by default, the shortest lived Exalted, with a mere 150 year lifespan).
- Inverted in Promethean: The Created, where mortality begins at twenty - a Promethean who completes the Great Work becomes a human in young adulthood, and can expect a normal lifespan from there on out.
- In the AD&D 2nd Edition setting Birthright, people can inherit divine bloodlines, which are generally assumed not to manifest until puberty. One such power is extreme long life, from five to one hundred times longer.
- The New World of Darkness book Immortals features a group of beings called the Purified, who became immortal through one of several rituals that involved dying and then coming back to life. No matter how old they were when they performed the ritual, when they come back to life, they always come back in a body that is physiologically in its mid-twenties.
- Juvenat treatments in Warhammer 40,000 retard ageing, but do not affect maturation—thus, nobles, Inquisitors, and other important people can appear to be in their thirties or forties at two to three hundred years of age. The treatments are not perfect, so the appearance of a very healthy 40-50 year old is most common, barring additional surgery.
- In one of the earlier Shadowrun sourcebooks, a researcher notes that elves seemed to have some kind of mechanism that caused their aging process to stop for a period of time, but there also were indicators of a latent reactivation trigger that would kick in after a couple of centuries. He then went on wondering what if there were a few that didn't have that second trigger.
- There are a few. Harlequin is one of them. He's outlived pretty much everyone and every civilization.
- Raine and Genis in Tales of Symphonia. A bit jarring in Raine's case as she looks the same age as her mother.
- As discovered later in the game, Kratos and Yuan both had their aging halted at twenty-something. Mithos, on the other hand, got it stopped when he was still a kid, and had to learn a special technique to make himself look older.
- Apparently the case for True Ancestors in Tsukihime. Arcueid looks to be slightly older than Shiki does, and looked that way around eight hundred years ago as well. Fridge logic implies that either she grew from infancy to full maturity very quickly, or she has always been an adult.
- The branded in the ninth and tenth Fire Emblem games age according to their beorc heritage until they turn sixteen, at which point their aging processes slow down to match their laguz heritage.
- In the Suikoden series; the True Runes keep their bearers from aging at all, leading to one character who's been physically a child for over three hundred years. The effects lasted long enough that they didn't even age while the Fog Ship Guide held onto the Soul Eater in Suikoden IV. Needless to say, Ted's a bit annoyed about this.
- However at least the runes allow bearers to hit puberty before the whole immortality thing sets in. Otherwise characters like Luc and Sasarai who are implied to have had their runes since birth would still be infants. The theory is that the rune stops aging at its prime as defined by JRPG standard (i.e. mid to late teens).
- Pretty much how the aging process for demons native to Veldime works in Disgaea 2.
- Averted with non-Veldime demons, who typically have 500 years worth of puberty to look forward to.
- Angels also have the same problem as demons from netherworlds apart from Veldime. Flonne is the oldest from the trio of main characters of the first game at 1509 (Etna and Laharl are 1470 and 1313 respectively) yet all of them look like there's no real difference apart from height.
- Touhou, especially in fanon, plays with this trope for all it's worth, thanks to it's Loads and Loads of Characters who are Really 700 Years Old. The scarlet sisters were born vampires, and Can't Grow Up, as are all of the fairies in the series, who are refered to in Perfect Memento as having at most the appearance of a 10-year-old child. Most of the others, however, are adults who have lived thousands of years, and include some apparent teenagers who are truly immortal. Yukari, especially, (thanks to dressing up and occasionally playing like a younger woman than she appears to be normally) gets jokes from fandom about being the "old maid" (in spite of only being a couple thousand years old, which is fairly normal by Touhou standards) by some corners, and having her boast that she's (eternally) seventeen by others.
- The fairies may not fully fall under this trope as they are elemental embodiments that are reborn each time they die (which may occur with the changing of seasons according to some interpretations) rather than being immortal or long lived. The fact that the fairy maidens from the Scarlet Devil Mansion appear older then those anywhere else would suggest that fairies can age to an extent, but usually die before it occurs in any meaningful way.
- After her powers manifested, Aya Brea of Parasite Eve actually got physically younger. While she actively refused to use her abilities between games, by the time Parasite Eve 2 rolls around, Aya is permanently 21.
- Ms. Fortune from Skullgirls has something like this. A stolen gem that she swallowed granted her immortality plus a wildly accelerated Healing Factor — which explains how she survived being chopped to pieces by Dahila and her goons who tracked her down to get the gem back. She hasn't aged a day since her supposed "death", and has worked out a way to use her newly-detachable limbs and head to her advantage in combat. Pity about the scars, though.
- Played with in Mass Effect. Averted by the asari, who are generally thought to leave childhood at forty, and are considered mature (if rather young) adults at 80. A century-old asari is considered "barely more than a child". They give live birth and just how long gestation takes is never stated, but given a conversation between an asari and her shorter-lived non-asari husband involving their two children, it probably is less than a decade. Krogan play the trope straight.
- Miranda states that because she was heavily genetically modified, she will likely live 50% longer than a normal human, and it is stated that her body is in its twenties even though she is in her thirties. She makes no mention of whether this affected her growth rate as a child, though her genetically identical, but much younger, sister Oriana grew up having a normal life, which would presumably be impossible if all ageing happened slower than normal, so presumably they play this trope straight.
- Béluga and Elh from Solatorobo zig-zag this trope together. Béluga plays it straight, appearing to be a young adult despite his age, but Elh averts it by being stuck as a teenager. After losing her immortality, she comments that she seems to have finally grown a bit after three hundred years.
- Human-passing Nobodies from Kingdom Hearts can be inferred to have this. Word of God states they don't age, but the Nobodies who lost their hearts as kids seem to have aged normally since the time when they would have become Nobodies, while their fully-grown counterparts haven't aged a bit in the intervening decade-or-so.
- In the Official Fan Remake of King's Quest II. Little Red Riding Hood is retconned into a girl named Possum whom lives with her elderly sick grandmother. her grandfather in his youth was turned into a vampire, though a friendly one. But went into seclusion ashamed of what he became. When he discovers that his elderly wife is going to die he turns her into a vampire so she can live with him and be eternally young (She actually takes on the appearance of a 30-40 year old) Where he also turns Possum, who being a squeaky voiced child, now is a deep voiced fully grown adult.
- Truth in Television, as far as medical science is concerned. Growth/maturation (which typically ends around 24 or so) is different to aging - the second is caused not by hormonal changes but by other factors. Thus, if somebody ever comes up with an immortality pill, it'd essentially "freeze" your age in your mid-20s. "Slowing down" the entire process, thus increasing the time spent in childhood, is presumably doable genetically, but pointless for extending someone's life - diseases already exist that have a similar effect (hi there, Gary Coleman!) but they don't increase life expectancy (quite the opposite).
- There was a girl who had a genetic condition that aged her at one twelfth of the rate of a normal human. When she was 16, she was still stuck in the body of a 1 year old, and for that matter the mind. She had genetic and developmental characteristics that have never previously been seen. It is very difficult to say how old she effectively was - cognitively she resembled someone under the age of a year old, she still had her baby teeth (but a full set of them, as if she was about 8 years old), she hadn't grown significantly since she was five or six years old, yet her bone's internal structure was more advanced than her age suggested (resembling that of a 10 year old)... she might have had an extremely long lifespan, but she died recently on October 24th, 2013 of a disease that commonly affects children.
- There are two other, similar examples, though it is unclear if the conditions are at all related - Nicky Freeman is over 40 years old but looks to be about 10, while Gabrielle Williams is considerably younger than Brooke Greenberg, but seems to be destined for the same path, weighing only 10 pounds when 6 years old. Both have physical disabilities beyond their seeming long-term youthfulness - both are blind and neither can speak.