History Main / ImmortalImmaturity

* In ''WesternAnimation/HazbinHotel'', AntiAntichrist [[ThePollyanna Charlie]] is over 200 years old but has the mentality of a girl in her late teens, and allows her EvilMentor Alastor to [[FauxAffablyEvil act like a father figure to her]] despite being a century his senior.

* ''Webcomic/KillSixBillionDemons'': Angels and demons are immortal, though demons change and shift their natures so often by moving through their FantasticCasteSystem of masks that a particular demon's current incarnation can be practically any age and will often act it too. A more tragic example are [[BigBadEnsemble the Seven]], who are all millennia old [[GodOfHumanOrigin Gods of Human Origin]] and are still the same fundamentally broken group of trauma victims they were [[FromNobodyToNightmare before they became immortal and powerful]] (the main exception being Jadis, who [[GoMadFromTheRevelation went mad seeing the True Shape and has basically nothing of her old personality left]]. [[spoiler:Mammon is also revealed in ''Seeker of Thrones'' to have changed significantly with age, although in his case [[AgeWithoutYouth he's gone senile]] and is, if anything, [[ScatterBrainedSenior even more immature than he used to be]]. At least it seems to have given him time to think and reflect on all the horrible things he did to get to his current stage.]]

A darker take of this would be where the immaturity is a facade, and the character does indeed have inner angsts and turmoils that most mortals actually wouldn't be able to relate to. For example, [[MayflyDecemberFriendship being immortal but having mortal friends]] would mean watching them age and eventually perish while you remain unchanged, and while you wouldn't have to wonder about what awaits you in the afterlife, the question of [[WhoWantsToLiveForever what will happen to you when the world ends and there are no more people]] remains. Thus, inner angst is generated over stuff that mortals don't have to worry about, but is kept hidden except for special circumstances when the immortal character gets the spotlight, when such issues are thrown into the light for HiddenDepths or CharacterDevelopment.

There is an argument to be made that absent changes to the body, the rate of 'change' to the mind slows even in real life; that is, the changes between birth and age 10 are vastly bigger than the changes from 10 to 20, which in turn are much larger than the difference between 20 and 40 or even 20 and 60. This argument would have it that absent the bodily changes of old age, the changes from 50 to 500 might not be so extensive as one would otherwise expect. It's also probable that a being with a longer lifespan could take a proportionately longer time to reach emotional maturity. A 100- or even 1000-year-old immortal alien might be the equivalent of a human ten-year-old, while for immortal children who find NotGrowingUpSucks (or [[LivingForeverIsAwesome rocks]]) it may well be that having their clock stopped at a certain age also froze their cognitive development. They may get smarter, but not wiser.

Another part of this trope is that very often the apparent ages of immortals correspond to their status, so that the leaders are in their 30s with teenaged followers, even when their apparent age should have no relationship to their true age.

* Mina Tepes from ''Manga/DanceInTheVampireBund'' seems to suffer from this intermittently. It is never made clear how much is an intentional put on, how much is her relaxing when not obliged to [[ToughLeaderFacade put up a strong front]], and how much is neither; but there are times it is hard to remember that she is older than fifteen... and [[TheHighQueen other]] [[ManipulativeBitch times]] when it is hard to mistake her (despite her [[UndeadChild height]] and [[OlderThanTheyLook figure]]) for anything younger than fifty.
* Devils in ''Anime/{{Dorohedoro}}'', despite being mysterious ageless entities with Godlike abilities worshipped by all sorcerers, are notorious for their childlike demeanor. They are quite fond of using their endless power and knowledge to perform petty pranks on sorcerers and to enjoy simple hobbies, games and tv shows. From throwing bird poop down on unfortunate bystanders to making living creatures out of pizza, almost every act done by devils throughout the series was for laughs and giggles. For example, Guragura spends most of his time pretending to be Shin's dog, Haru produces music and plays in a band of other devils, and let's not even get started with Chidaruma.

** [[GodOfEvil God of Destruction]] Beerus is an immature {{Jerkass God|s}} who can be very childish, and acts like a SpoiledBrat. Always seeking out his favorite food, and prone to temper tantrums over petty reasons.

* ''Manga/FrierenBeyondJourneysEnd'': Frieren herself acts like a child in many ways and likes being babied despite being at least a millenium old. However, this only applies when they aren't in danger, in which case she's a deadly mage.

** Tuka Luna Marceau is a 165 year old elf, but she looks and acts like a teenager. By the standards of her race, she ''was'' a teenager.
** Rory Mercury is 961 years old, but usually acts like a FilleFatale 13 year old. However, she is perfectly capable of acting mature if she has to, like in an epic scene where she scolded a person who was disrespecting and criticizing soldiers.

* The Wolkenritter from ''Franchise/LyricalNanoha''. Vita looks like a child, and acts like a child -- though it could be fairly said that she's just immature, which is a problem that doesn't automatically go away with age. Her rather sucky role in life up to that point, and during the second season, probably also contributed to her lack of control via lots of emotional pain. Still, it's awfully coincidental that the most child-like Knight in appearance would be the most childish in behavior, given that they're all supposed to be the same age.
* In ''[[Manga/MermaidSaga Mermaid's Scar]]'', a subversion occurs when an immortal who has lived for 800 years as an 8 year-old boy only ''acts'' as a child to keep up appearances; his mind is anything but childish.

* In ''Anime/PokemonTheSeries'', Mew is a PhysicalGod and one of the oldest beings in existence, but still behaves like a young child.
* [[{{Dhampir}} Lety]] from ''Manga/TheRecordOfAFallenVampire'' is [[ReallySevenHundredYearsOld Really Fifty-Six Years Old]] but looks and acts like child (well, a child with [[SmallGirlBigGun incredible sniper skills]]). Her excuse: if she acted her real age it would appear "unnatural" and she'd have a harder time hiding among humans.

* ''ComicBook/TheLeagueOfExtraordinaryGentlemen'': Orlando, an immortal who periodically changes gender, gained their immortality around 1300 BC, and has barely matured or changed at all since then, being frozen in their 20's, and living an eternal life revolving around sex and fighting. It's not until The War On Terror in the early 21st century that the cracks begin to show. By contrast, Mina Murray and Alan Quatermain don't even last a full century of immortality before the premise of eternal youth begins to lose it's luster, especially for Mina.
* One of the subplots in the latter part of ''ComicBook/{{Preacher}}'' is the general immaturity of the vampire Cassidy, and its destructive impact on not just himself but the people he comes into contact with.

* ''Fanfic/ChildOfTheStorm'' notes this with Asgardians, who routinely live for over 5000 years (which is summed up as being their 'three score and ten'). While they hit physical maturity [[ImmortalityBeginsAtTwenty at about the same age as humans]], mental maturity is a very different matter. By this standard, the 1500 year old Thor and Loki are... 21. This explains a great deal about their previous behaviour, to the point where Thor's teenage son, Harry, sometimes comes off as more mature than they were until very recently. However, it's also very heavily implied to be circumstantial - Asgard and the other higher realms are pretty static thanks to the long lifespans, meaning that things and people don't have to change very quickly. When they end up on Earth for an extended period (and particularly in Thor's case, have parental responsibilities), they mature much, much faster, to the point where Thor is the Avengers' TeamDad. A similar case appears with Sunniva - who's about 1800 a.k.a. 25 - at the start of ''The Phoenix and the Serpent'', who spends several months on Earth during the last Ice Age following [[spoiler: Harry's]] trail and undergoing a ''lot'' of CharacterDevelopment.

* ''Film/LetTheRightOneIn'' features Eli, a vampire who has been twelve for [[ReallySevenHundredYearsOld 'a very long time']]… but still acts pretty much exactly like a twelve year old. It is widely debated among fans, however, just how much her immaturity is the real Eli and how much is an act put on for the sake of getting a new [[TheRenfield Renfield]].
* Mr. Magorium of ''Film/MrMagoriumsWonderEmporium'' certainly counts. Of course, he does owns a magical toy store...

* In ''Film/{{Thor}}'', Thor Odinson is several centuries old, but acts like a [[RoyalBrat spoiled brat]] with a HairTriggerTemper. It takes being reduced to a mere mortal for him to finally mature.

* If anything, the movie ''Film/TheOldGuard'' is a subversion where centuries and millennia of experience have made the immortals more well adjusted, genuinely good people. Most notably, the homophobia that some bigoted soldiers show is called infantile by one of the immortals.
* ''Film/LetMeIn'' shows Abby. At first she seems to be inverting this trope because she is clearly more dominant in the relationship with her caretaker Thomas. But in the course of the plot it becomes clear that she is really stuck in the mindset of a 12 year old. She behaves innocently and childlike, likes to play with toys and puzzles, and is also completely ignorant of social norms. So she crawls naked into bed with Owen to cuddle with him and doesn't understand what he's upset about. Abby also kills a jogger, and just leaves the body lying there, which makes Thomas angry. The investigator who investigated the series of murders was able to find out very quickly where she lived. Finally she leaves town with Owen. It is unknown whether she turned Owen into a vampire or whether he will become her new caretaker. But as a caretaker, he would be a terrible choice because Owen is frail, shy, sensitive and skinny. So it's probably a childish crush that leads Abby to take Owen with her.

** Paladine's more EccentricMentor than anything. He may ''act'' eccentric and amusing, but even as [[CloudCuckooLander Fizban]] he's always on top of what's going on.

* {{Lampshaded}} in ''Literature/{{Everworld}}'' — while most of the gods that the protagonists had met up until that point were psychopaths, seeing a whole pantheon together on Olympus really helped them see how [[TheGodsMustBeLazy lazy]], [[ItsAllAboutMe self-obsessed]] and petty they could be. April actually figures out that gods cannot change — their personalities are set based on their role, so that getting them to act contrary to that position is nearly impossible. Athena, the OnlySaneMan among the gods, confirms this.

* In "Literature/TheGypsiesInTheWood", Charles Beauregard investigates a series of incidents in which TheFairFolk [[ChangelingTale steal and impersonate children]]. At the end, he reflects that in his experience the Fair Folk are themselves much like children in some ways, selfish and given to extremes of emotion, "prone to spasms of joy and long rainy afternoon sulks", aptly called the ''little people''.
* ''Literature/HarryPotter'': {{Justified|Trope}}. [[Characters/HarryPotterMagicalBeings Moaning Myrtle]] is the ghost of a Hogwarts student who died when she was fourteen, fated to walk the Earth for eternity (as all souls who choose to linger as ghosts instead of moving on are in this setting). Half a century after she died, she still behaves like an excitable girl with a childish crush on Harry since she's frozen at the age she died at.

* ''Literature/HonorHarrington'' occasionally addresses the implications of slowing the aging process and how much of your personality is influenced by hormone levels based on your age. Puberty and its associated mood swings has years added on to it.
* {{Invoked|Trope}} in Creator/NKJemisin's ''Literature/InheritanceTrilogy'' by Sieh, the god of childhood and mischief. Even though he's the [[TimeAbyss unutterably ancient]] first creation of the Three [[TheOldGods Old Gods]], he chooses to embody his affinity fully, and almost always acts like a ten-year-old (albeit an all-powerful TykeBomb one). Indeed, acting like an adult or undermining the concept of childhood sickens and weakens him.
* In Creator/JRRTolkien's legendarium the Men see Elves as eternal immature children. Justified, since their maturization would take centuries - and whereas the Noldor could be at best described in ''Literature/TheSilmarillion'' as [[PsychopathicManchild Psychopathic Elder-Children-of-Eru]], they have matured a lot in the 7000 years before the events in ''Literature/TheLordOfTheRings''.

** Virtually every immortal is narrow-minded, short-sighted, vindictive [[JerkAss jerks]] prone to throwing tantrums or taking petty revenge for an slight real or imaginary. Its kind of expected from the gods given how [[JerkAssGods they are portrayed in the series]], and the main character explicitly points out that in the cases of pantheons like the traditional Irish pantheon (who actually started out as mortals), they weren't ''expected'' to be anything else. That said, there are a few exceptions, such as [[JesusWasWayCool Jesus]].

* Avoided at first with Eli, a vampire who's been [[ReallySevenHundredYearsOld twelve for a long time]] in ''Literature/LetTheRightOneIn''. She doesn't act or think like a child, but begins to (possibly subconsciously) do so when she starts hanging around with the main character.
* Notably averted in the case of The Lord Ruler of ''Literature/MistbornTheOriginalTrilogy''. His extreme mastery of allomacy [[spoiler: and feruchemy]] gives him functional immortality as a strong, healthy, youthful man. Almost every encounter with him, however, goes to great lengths to stress how [[SeenItAll ancient, tired, and apathetic he comes off as]] despite his outward vigor.

* In ''Literature/TheSecretsOfTheImmortalNicholasFlamel'', Billy the Kid, who was still a young man when he was given immortality, and, well, lives up to his nickame. His main immature traits are [[PopCulturedBadass constantly referencing movies and TV]] and [[DrivesLikeCrazy being a reckless driver]].

* This is pervasive throughout the ''Literature/SkulduggeryPleasant'' series - many of the magic-wielding characters are centuries old, they can live for up to two thousand years if they're particularly powerful (use of magic explicitly stalls the ageing process past 18-25), and they often act incredibly immature. Or at least, not with the maturity you'd expect from someone who is ReallySevenHundredYearsOld. Tanith Low, for instance, first appears at the age of 80 something and is described by her best friend and one of the protagonists, Valkyrie as, 'looking about 20 and acting about four'. It's hinted that one of the loopier characters is onto something when in a moment of lucidity, she points out that chronological age and biological age are very different in terms of thought processes - essentially, young brains and old brains think very differently.

** A more frightening take on this is the immortal children: a child who becomes a vampire will never be able to gain the self-control of an adult vampire, and will instinctively slaughter everything instead. Combine that with super-vampire strength, speed, etc. and the supernatural ability to make anyone who lays eyes on them fall obsessively in love and fight to the death to protect them, and it's no wonder it's illegal to bite children.

** Ramiris is just as old as Milim and goes through a constant cycle of death and rebirth, maintaining all her memories from past incarnations. Her current incarnation will fully mature in about 100 years from when the story starts. However, comments from other characters imply she's alway acts like a 20-something NEET.
** Veldora is older than Milim, but tends to look and act like someone in his early 20's absolutely obsessed with manga.

* ''Literature/TheTwelveKingdoms'': There are immortal characters who are over a hundred years old, but still act and consider themselves as teenagers. Immortality here stops not only someone's physical maturation, but also their mental and emotional maturation. An immortal who looks 12 years old effectively still is 12 years old regardless of how old and experienced they actually are.
* The White Queen in ''Literature/TheUnexploredSummonBloodSign''. Her actual age is unknown, but she looks like a teenager, and acts like a small child. [[spoiler:This includes having no empathy for anything except the sole thing she's interested in. She has no problems with destroying the world if it gets her what she wants]].
* In ''Literature/{{Warbreaker}}'', this is [[InvokedTrope enforced]] on the immortal [[spoiler: Susebron, [[GodEmperor God King]] of Hallandren]] by [[spoiler: his priests]], who have stunted his emotional growth by cutting out his tongue so he can't speak, refusing to teach him to read and write the common script, and sequestering him within one location and witholding most information about the outside world. As a result, he's incredibly [[WideEyedIdealist naïve and innocent]] for his age, [[LiteralMinded doesn't understand social cues]] such as sarcasm and flirtatiousness, and doesn't even know how children are conceived, having gotten the idea from a children's storybook that all that's required to make a child is for a man and a woman to spend a night in the same place.
* The fey in ''Literature/WickedLovely''. They are immortal, or at least ReallySevenHundredYearsOld, but they very rarely act or look anything more than early-twenties. Probably the best example is Keenan, who is a 900 hundred year old teenager in pretty much all respects.

* Soldier Boy from Amazon Prime’s ''Series/{{The Boys|2019}}'' is a superhuman that’s over 100 years old and yet he behaves more like a spoiled teenager or a Fratbro. His narcissism, NighInvulnerability, [[spoiler:and privileged upbringing]] has prevented him from understanding or caring about the consequences of his actions. For 78 years he’s never had to worry about death, disease, aging, getting a job, or getting arrested.

* Trelane, in the ''Series/StarTrekTheOriginalSeries'' "[[Recap/StarTrekS1E17TheSquireOfGothos The Squire of Gothos]]", is an extremely powerful near-god and hundreds if not thousands of years old, but acted like a child...and by the standards of his race, he was--''his parents'' showed up at the end to drag their whining kid home.

** Q from the ''Series/StarTrekTheNextGeneration'' started off this way: looks to be 30, huge ego, power to match. He intentionally introduced the Federation to the Borg and put "Humanity on trial" just to make things interesting and test to see that Humanity had what it takes to be allowed to even exist. This childish behavior went on for a few seasons before the other members of the Q continuum punished him for the above mentioned reasons by taking away his powers and temporarily leaving him as a mortal. This lead to some CharacterDevelopment in ''Series/StarTrekVoyager''. He still liked to show up unexpectedly and sometimes pull off the occasional harmless prank, but there were bigger problems going on in the Q continuum that forces him to be more mature. (A popular fan theory is that Q is Trelane's older brother.)

* Rebekah from ''Series/TheVampireDiaries'' is a 1000-year-old vampire who's interested in cheerleading, boys, and the prom. Curiously, her brothers (except for Kol) actually do act their age, leading to some fans to ponder whether a double standard is at work.
** Damon Salvatore qualifies as well being impulsive, decadent and obsessed with Elena.

* The [[Myth/ClassicalMythology ancient Greek]] gods are constantly interested in the affairs of mortals; they also breed with mortals. They don't seem to learn anything from experience, as far as wisdom is concerned. They are petty, cruel and constantly fighting amongst each other.
** The train of events that led to UsefulNotes/TheTrojanWar began with Eris getting pissed over not being invited to a wedding. (The modern day religion of UsefulNotes/{{Discordianism}} uses this tale as its jumping-off point.) Granted, she's the goddess of discord, but the fact that [[TheHighQueen Hera]], [[LoveGoddess Aphrodite]] and ''freakin' [[BadassBookworm Athena]]'' took the bait and let a beauty contest escalate into a decade-long war shows how shortsighted the gods can be.

* For changelings in ''TabletopGame/ChangelingTheDreaming'' this trope is essential if they want to keep their Fae side intact. Though changelings tend to age much more slowly than other humans, eventually Banality will weigh heavily on their Fae souls and they become [[BroughtDownToNormal Undone]]. They constantly struggle to resist [[GrowingUpSucks the pressures of growing]] up to hold on to their magic and immortality for as long as they can. Changelings are basically humans who have been given an Immortal Fae soul that may have been a powerful being in of itself and is merely body-hopping to survive. The humans they inhabit tend to be quite young. So it is possible, and quite common, to have a millennium old legendary dragon-slayer, a highly respected duke of the Seelie Court, or a highly valued scholar of ancient lore sitting in a living room playing with toy trains until mommy calls him for bedtime.

* The 200-year plus necromancer Liliana Vess from ''TabletopGame/MagicTheGathering'' is fully revealed to be this once she joins the Gatewatch: highlights include pranking Jace by rearranging his books, refusing to refer to Gideon as anything other than variations of the term "beefcake" and goading the already immature and impulsive (due to actual youth) Chandra into getting into trouble, to the point that [[EveryoneHasStandards even she]] calls her out on this:

* Subverted in the ''TabletopGame/{{Ravenloft}}'' supplement ''Van Richten's Guide To Vampires'', which proposes that vampires go through a psychological maturation-process which ''commences'' when they become undead, and is entirely independent of their mortal age. An octogenarian who becomes a vampire can regress to teenage-brat behavior, while a child-vampire who's (un)lived long enough can become a sober, calculating {{Chessmaster}}.
* Vampires in White Wolf's ''TabletopGame/VampireTheRequiem'' and ''TabletopGame/VampireTheMasquerade'' canonically tend to be "frozen" at where they were when they first became Vampires. They do become more knowledgeable and powerful, but they often keep the same prejudices and emotional maturity they had from when they were still alive. Therefore, even though a vampire may be 200 years old, he could still act like a hot-tempered 17 year old. Functionally, this trope pops up a lot due to the simple fact that a bunch of mortal players are dictating the characters' every action on the fly.

* The angels and demons in the ''Franchise/{{Disgaea}}'' series are all over a thousand years old, but since time flows differently in their dimensions, they age 100 times slower then normal and act exactly as old as they look.

* Xiaomu of ''VideoGame/EndlessFrontier'' and ''VideoGame/NamcoXCapcom''. She may be a 700+ year old sage fox, but she can be immature about certain things, enough to be even spanked for them.

** In ''VideoGame/FireEmblemShadowDragonAndTheBladeOfLight'' and ''[[VideoGame/FireEmblemMysteryOfTheEmblem Mystery of the Emblem]]'', Tiki, a Manakete (basically a WereDragon) looks and acts like a little girl, in contrast to the other manaketes who act maturely. This is eventually [[{{JustifiedTrope}} justified]] as its revealed all but 10 of Tiki's years of life was spent in a forced sleep and in the ten years she had awake, she spent with her stepfather Bantu raising her as a normal girl. Also [[spoiler: Xane]] is revealed to be a Manakete as well and looks like a teenager, yet he usually acts like a childish clown. This is eventually revealed to be partly an act as [[spoiler: Xane]] is eventually revealed to be [[SadClown sad and cynical on the side]] after having seen the fall of dragon kind.
** In ''VideoGame/FireEmblemAwakening'' (a [[BroadStrokes loose]] sequel to ''Shadow Dragon''), Tiki is the much revered and millennia old Voice of the Divine Dragon, who normally acts wise and aloof, but her profile explicitly mentions that she also has a more childish side. [[LadyOfWar Say'ri]] experiences this firsthand when Tiki first [[BlowingARaspberry Blows A Raspberry]] at her and then tries to stuff her mouth with an apple in their B support.
*** From the same game, Nowi is another Manakete and a young Tiki Expy, just like her she is more than hundreds years old, but has the looks and mindset of a young girl. English only material says that this is at least partly a case of ObfuscatingStupidity. Japanese material and English DLC says its ProportionalAging.

* Many ''Franchise/TouhouProject'' characters, though it might be side-effect of how most characters are immature and most are ReallySevenHundredYearsOld, with predictably frequent overlap.

** All fairies are excellent examples of this trope, which is justified due to TheFogOfAges and usually being on the ''[[OlderThanTheyLook younger]]'' end of the immortal scale. [[SmallNameBigEgo Cirno]] is probably the most notable among them and one of the biggest [[TheDitz ditzes]] in the franchise, followed by Clownpiece, who is implied to have lived since at least the times of ancient Greece, but is willing to set the house of her landlord on fire ''[[ItAmusedMe for fun]]''. The Three Mischievous Fairies are a less certain case as it isn't made clear on whether or not they're actually older than humans age-wise.

* ''VideoGame/{{Xenogears}}'' features several characters who are quasi-immortal. Some have lived for hundreds of years, a few for as many as ten thousand. [[spoiler: Emperor Cain and the Gazel Ministry]] act as one might imagine. The former is a world-weary, very old man who has kept his moral compass intact due to guilt over a sin committed long ago, the latter being very anxious to transcend to a higher level of existence and possessing of no moral compass whatsoever. Then, there is [[spoiler: Miang]], who has lived as long, but in a different manner: she possesses a new body when her current one dies. When we meet her, she has the body of a beautiful young woman and appears to act like one, being flirtatious and sexually-active. Yet, it's difficult to tell how genuine this is, because her entire existence is devoted to executing the mother of all {{plan}}s, and everything she does serves this end.

*** [[spoiler:Hanyuu, a.k.a Oyashiro-sama]], who's even older, but is really quite shy and easily flustered. As it turns out, this is also much of an act (though not ''all'' of it). [[spoiler:For one, Hanyuu died as an adult]]. There are multiple times where she drops the act and seems as mature as expected from her (which is jarring because her current form is [[spoiler:that of a CuteGhostGirl]]). The anime adaptation [[CharacterExaggeration exaggerated]] her immmaturity while dialing down her maturity.

*** Beatrice is perfectly capable of being the dignified and elegant witch that she claims to be, but is often very childish and [[TheGadfly mischievious]]. [[spoiler:This is because she's not actually [[ReallySevenHundredYearsOld a thousand years old]] like she claims. She's actually [[ArcNumber 19]] years old]].
*** Lambdadelta is supposedly a great witch herself, but usually comes across as something of a [[TheDitz ditz]] who's [[PsychoLesbian obsessed]] with fellow witch Bernkastel. [[spoiler:Another subversion, since her childish behaviour is really just an act]].

* Mab and most of the other Fae from ''Webcomic/DanAndMabsFurryAdventures'', sort of. Essentially everything they do is a matter of "ItAmusedMe," but they operate and think in an entirely different way from anyone else, and evidence suggests that they can also be mature if that's what amuses them at the time. Additionally, since they're immortal and have a flexible view of time, this behavior might be a way to avoid going totally insane. There is also a somewhat sinister slant to their apparent immaturity, especially given their general view of things as being a game of sorts, and that fact that despite near-omnipotence they will still allow their friends to die in preventable ways.

*** Incubi and succubi in general are creatures of emotion, and apparently have a harder time controlling their own in turn, though the clan leaders are more than capable of being serious - perhaps because they are millennia old. Demons have no such excuses, however.

** Thor provides the page image. He's bit of a frat boy at heart, but he's also one of the gods who actually cares for mortals, [[spoiler:especially when the other gods contemplate ending the world to contain the threat of the Snarl.]] When he shows up in person to explain the threat he's a lot more focused.

* In ''Webcomic/TemplarsOfTheShiftingVerse'' Augustus, Loria and Dantes all became immortal at an early age -- so they have limited real life development outside of their adventures.

** Princess Endorsi Jahad reportedly didn't even start climbing the Tower (ie. become a Regular) until she was around 300 years old, but she acts like a mildly sociopathic, hyperacive teenager, refusing to take responsibility, freaking out whenever someone accidentally implies she's not the prettiest girl around, and kicking people in the head when she's displeased. The older princess and High Ranker Yuri Jahad is like a more mature version of her, but that's only relatively more mature. [[ItMakesSenseInContext Yuri once manages to convince her own weapons she's an idiot.]]

* {{Justified|Trope}} in ''WebOriginal/SeventeenThousandSevenHundredSeventySix'': After 15 000 years of CompleteImmortality, humanity has settled into a comfortable [[TheAntiNihilist Anti-Nihilist]] rut, spending their time on hobbies like ever-more-absurd variants of football. The newly self-aware AI Nine finds it uncanny, but Ten explains that past a point, comfort and familiarity took precedent over ceaseless striving.

*** Ironically, the series implies many of them were once worse. Oberon leveled a 1,001 year exile to force them to grow up. It worked on a few of them. (Extra ironically: some are actually more mature than [[HairTriggerTemper Oberon himself]] now.)
* [[BewareTheSillyOnes Bill Cipher]] of ''WesternAnimation/GravityFalls'' has lived for trillions of years, but half the time acts like this creepy clown or sadistic comedian. The way he describes his plan to invade our dimension sounds more like a guy who's planning to hit the town with his buds than universal domination. According to the show's creator, "Bill is a character who's been around for countless billions of eons, but he hasn't grown up in that time." [[{{Foil}} This helps highlight the show's]] ComingOfAgeStory, especially as the last few episodes juggle Bill's invasion with the twins trying to define themselves as they reach teenage-hood.

** Wonder Woman often acts like a young girl (especially when dealing with her mother, Hippolyta), despite physically being a twentysomething woman and actually being several thousand years old. Possibly justified since she spent most of her life on Themyscira under her mother's rule, cut off from the outside world.

** Skillit is 4,000 years old who also knew previous wearers of the mask but he is a {{Psychopathic Manchild}} who thinks hurting people and playing with their spines is fun which understandably disturbs The Mask.
** The Mask is a cartoonish man who is genuinely insane and even though if he decides not to take his face off and keep it on he is pretty much immortal as he does not age or get killed however he acts and behaves like a kid, has a short attention span of one as he gets easily distracted by trival things, tends to be too strong towards any woman he sees, just wants to have fun and dance at the Coco Bongo but he is a good hearted man who also cares about his friends, the people who live with him in Edge City even if they annoy him at times and does not like hurting people or killing them or even wants to as he finds out that Skillit's idea of fun involves all of those things that he hates and he does put himself back on track once he sees that everyone is in danger which that he even in his most chaotic state of mind will go over and save them all with success.

** This is justified and {{deconstructed|Trope}}, as each gem is BornAsAnAdult and will never die by natural means. They have no lifespan or life cycle and as such have no natural reason or method with which to change over time, barring extreme circumstances that they subsequently never move on from. It takes Steven, who as a HalfHumanHybrid does age and developed, to teach various gems how to grow as people.

** Peridot is an unspecified amount younger than Amethyst, but still thousands of years old. She parrots Steven's EyelidPullTaunt, is fond of name calling, and finds slapping other people/gems amusing. When she loses her limb enhancers, it's revealed that she's only about Steven's height, and acts progressively more childlike, even mimicking laser sounds ("Take that, Cluster!") just like a kid.
** Rubies are a [[HiveCasteSystem caste]] of [[RedShirt disposable grunts]], designed for a focus on [[DumbMuscle raw strength over intelligence]]. Consequently, they're all very lacking in emotional intelligence — even Eyeball, who's more serious than the other Rubies (and also the oldest of her squad, and a veteran of the war between Homeworld and Rose Quartz's rebellion over Earth), is [[PsychopathicManchild impulsive and short-sighted to a dangerous degree]]. This, along with their short-stature ([[LargeAndInCharge indicative of their low rank]]), basically makes them Homeworld's [[AdorableEvilMinions army of immortal munchkin brats]].
** Lampshaded in [[Recap/StevenUniverseS4E15TheNewCrystalGems "The New Crystal Gems"]]. Lapis, Peridot and Connie pretend to be the Crystal Gems to do their job while the regular team is [[spoiler:in space]]. When Peridot and Lapis cause damage while fighting over who gets to be Garnet, Connie tries to give one of Steven's speeches, but falls flat on her face. Lapis and Peridot begin to fight and throw insults back and forth, until Connie snaps.

* ''WesternAnimation/{{Wakfu}}'': [[spoiler:Qilby]] the Traitor is a nigh-unique eternal being who's been around for roughly as long as the universe in which he resides, and unlike most of the Eliatrope Council of Six he perpetually retains ''all'' his memories. He's also incredibly selfish, manic, petulant and immature; callously committing acts of planetary destruction so he can satisfy himself by [[spoiler:ensuring he's [[AllergicToRoutine never bored]]]] and throwing tantrums when his BerserkButton is pressed. Then again, it's subtly implied that Qilby might've once been a genuinely wise immortal being, but [[spoiler:the unenviable combination of WhoWantsToLiveForever and ''eidetic memory forcing him to memorize every '''moment''' of eternity'' warped and devolved his mind]].

* ''WesternAnimation/YoungJustice2010'': [[CreepyChild Klarion]] is a HumanoidAbomination who is "ageless" yet looks like he might be twelve. He can cause [[PersonOfMassDestruction worldwide supernatural chaos]] in-between bizarre puns, pouting at other supervillains and getting into arguments with his [[{{Familiar}} cat Teekl]]. {{Averted|Trope}} by the show's other immortals, Vandal Savage and [[ImmortalityInducer Ra's al Ghul]], who are both evil but generally more mature.

* Soldier Boy from Amazon Prime’s ''Series/TheBoys'' is a superhuman that’s over 100 years old and yet he behaves more like a spoiled teenager or a Fratbro. His narcissism, NighInvulnerability, [[spoiler:and privileged upbringing]] has prevented him from understanding or caring about the consequences of his actions. For 78 years he’s never had to worry about death, disease, aging, getting a job, or getting arrested.

* Soldier Boy from Amazon Prime’s ''Series/TheBoys'' is a superhuman that’s over 100 years old and yet he behaves more like a spoiled teenager or a Fratbro. His narcissism, NighInvulnerability, [[spoiler:and privileged upbringing]] has prevented him from understanding or caring about the consequences of his actions. For 78 years he’s never had to worry about death, disease, getting a job, or getting arrested.

* Soldier Boy from Amazon Prime’s ''Series/The Boys'' is a superhuman that’s over 100 years old and yet he behaves more like a spoiled teenager or a Fratbro. His narcissism, NighInvulnerability, [[spoiler:and privileged upbringing]] has prevented him from understanding or caring about the consequences of his actions. For 78 years he’s never had to worry about death, disease, getting a job, or getting arrested.

* Soldier Boy from Amazon Prime’s ‘’Series/The Boys’’ is a superhuman that’s over 100 years old and yet he behaves more like a spoiled teenager or a Fratbro. His narcissism, NighInvulnerability, [[spoiler:and privileged upbringing]] has prevented him from understanding or caring about the consequences of his actions. For 78 years he’s never had to worry about death, disease, getting a job, or getting arrested.

* Soldier Boy from Amazon Prime’s The Boys is a superhuman that’s over 100 years old and yet he behaves more like a spoiled teenager or a Fratbro. His narcissism, NighInvulnerability, [[spoiler:and privileged upbringing]] has prevented him from understanding or caring about the consequences of his actions. For 78 years he’s never had to worry about death, disease, getting a job, or getting arrested.

* ''Literature/HarryPotter'': {{Justified}}. [[Characters/HarryPotterMagicalBeings Moaning Myrtle]] is the ghost of a Hogwarts student who died when she was fourteen, fated to walk the Earth for eternity (as all souls who choose to linger as ghosts instead of moving on are in this setting). Half a century after she died, she still behaves like an excitable girl with a childish crush on Harry since she's frozen at the age she died at.

* Edward and his siblings from ''Literature/{{Twilight}}''. With the exception of some very adult takes on death and sex, they all act like the teenagers they look like. It's explained in the books that this is a result of becoming a vampire; the ex-human is frozen in time both physically and mentally. Doesn't explain why Bella thinks that Edward is oh-so-mature though.

* Virtually every immortal from the ''Literature/IronDruidChronicles'' are narrow-minded, short-sighted, vindictive [[JerkAss jerks]] prone to throwing tantrums or taking petty revenge for an slight real or imaginary. Its kind of expected from the gods given how [[JerkAssGods they are portrayed in the series.]] Yet, mortals who became immortal are almost always the same including the [[NominalHero main character]]. There are a few exceptions, such as [[JesusWasWayCool Jesus]].

* [[UltimateLifeForm Shadow]] from ''VideoGame/SonicTheHedgehog'' is over 50 years old, but is physically the same age as [[TheRival Sonic]], who is only 15. As a result, Shadow acts like an angsty teen and has his childish moments, especially in the [[ComicBook/SonicTheHedgehogArchieComics Archie comics]].

* In ''Film/{{Thor}}'', Thor Odinson is several centuries old, but acts like a spoiled brat with a HairTriggerTemper. It takes being reduced to a mere mortal for him to finally mature.
** [[CainAndAbel Thor's younger brother, Loki]], definitely comes off [[RoyalBrat this way]], sometimes, but that might have less to do with immaturity and [[DespairEventHorizon more to do with the fact that]] [[InferioritySuperiorityComplex he's quite]] [[MadGod insane]].

** Thor provides the page image. He's bit of a frat boy at heart, but he's also one of the gods who actually cares for mortals, [[spoiler:especially when the other gods contemplate ending the world to contain the threat of the Snarl.]]

** Xykon is not particularly mature for an immortal lich with more than a century of life behind him. ''Start Of Darkness'' reveals that he was never very mature to begin with, even as an eighty-year old man. He even lampshades how, even at his advanced age, his "life's wisdom" boils down to little more than "sure, being a badass villain is a barrel of laughs, but what's the point if you can't even enjoy the little things in life" (which to him is mostly watching people die gruesomely and drinking coffee[[note]][[spoiler: and he's [[{{ChewBubblegum}} incapable of enjoying coffee anymore]]]][[/note]]). That said, Xykon can be surprisingly clever and patient if he ''wants'' to.

* ''WesternAnimation/JusticeLeague''[='s=] version of ComicBook/WonderWoman often acts like a young girl (especially when dealing with her mother, Hippolyta), despite physically being a twentysomething woman and actually being several thousand years old. Possibly justified since she spent most of her life on Themyscira under her mother's rule, cut off from the outside world.
** Mordred, the son of Morgan La Fay, has a severe case of this. His mother used her magic to stop his physical growth so he doesn't age until he's ready to be a king, but in doing so evidently also stunted his emotional growth, since he still acts like a ten-year-old RoyalBrat. [[spoiler:This is exploited by the heroes, who trick him into using his magical power to turn himself into an adult, [[AgeWithoutYouth which works a little too well for him]]]].

* ''VideoGame/IWasATeenageExocolonist'': The character known as Symbiosis is actually the WetwareBody of an AI that is thousands of years. However, the experience of having a ''human'' body [[EmergentHuman is extremely new to him]], which causes him to respond to many situations as if he were a child. Dys, the only other colonist besides the protagonist who knows of Sym's existence and hence spends any amount of time with him, is baffled by how he can flip-flop between mentioning memories only a TimeAbyss can have and enjoying things most humans have outgrown by the time they reach the young adult age Sym is presenting as.

* {{Lampshaded}} in ''Literature/{{Everworld}}'' — while most of the gods that the protagonists had met up until that point were psychopaths, seeing a whole pantheon together on Olympus really helped them see how [[TheGodsMustBeLazy lazy]], [[ItsAllAboutMe self-obsessed]] and petty they could be. April actually figures out that gods cannot change — their personalities are basically set based on their role, so that getting them to act contrary to that position is nearly impossible. Athena, the OnlySaneMan among the gods, confirms this.
* High Elf Archer from ''LightNovel/GoblinSlayer'' is 2000 years old and is far older than the rest of her party, but her behaviour (sheltered, easily provoked, and uncouth) makes her the least mature of them all.

* Chizuru of ''LightNovel/{{Kanokon}}''. On the one hand, she ''is'' a [[AsianFoxSpirit fox spirit]], with all the instincts that entails, but on the other, she's ''four hundred years old'', so you'd think she'd know that trying to rape a young boy is bad manners. Her mom is a little better but still has entirely too much fun with said young boy herself.

* Tet from ''LightNovel/NoGameNoLife'' looks and behaves like a child, despite being the PhysicalGod of Games.

* Mina Tepes from ''Manga/DanceInTheVampireBund'' seems to suffer from this intermittently. It is never made clear how much is an intentional put on, how much is her relaxing when not obliged to [[TheWomanWearingtheQueenlyMask put up a strong front]], and how much is neither; but there are times it is hard to remember that she is older than fifteen... and [[TheHighQueen other]] [[ManipulativeBitch times]] when it is hard to mistake her (despite her [[UndeadChild height]] and [[OlderThanTheyLook figure]]) for anything younger than fifty.

** Peridot is an unspecified amount younger than Amethyst, but still thousands of years old. She parrots Steven's EyelidPullTaunt, is fond of name calling, and finds slapping other people/gems amusing. When she loses her limb enhancers, it's revealed that she's only about Steven's height, and acts progressively more childlike, even mimicking laser sounds ("Take that, Cluster!) just like a kid.