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Say you’re a villain. You’re up against a team of heroes and you need a sure-fire way to rattle them. What do you do? Well, the best way to get everybody worked up is to threaten ''that'' character, the one whom the whole team feels they need to protect. Congratulations, you’ve just found Everyone's Baby Sister (or Brother).

When a BigBad sets this character in their sights, it immediately [[ItsPersonal becomes personal]] for every other character involved. Somehow, [[DidNotThinkThisThrough it never occurs]] to the BigBad that this may well make the heroes ''more'' dangerous, not ''less''.

Everyone's Baby Sister is most common in works where some of the characters do jobs that regularly put them in harm’s way and that exacerbate their protective instincts, and some of the characters work in safer environments where they’re not supposed to be at risk of physical harm. A [[TheTeam team]] composed of law enforcement officials and scientists or analysts is common here. This character will typically be a younger character who is not usually in any sort of physical danger and, thus, may appear physically smaller and weaker than the other characters. Other characters will feel protective of this character because of a combination of their older age, superior physical strength, and sometimes their occupational responsibility. When something happens to a character and even the {{Jerkass}} is unsettled by it, you have a winner.

Sometimes these characters inspire this reaction because they’re [[TheCutie impossible to dislike]]. Other times, the character really isn’t very likable at all; it's just that the other characters feel responsible for them. Because main characters tend to be the [[ActionHero Action Heroes]], this character is more often a supporting character than a lead (although it's not impossible for an equally heroic character to fit this trope by being TheOneWithAPersonalLife). By coincidence or design, these characters are often dorky TeenGenius types (or early to mid twenties genius, as the case may be), though this is certainly not a prerequisite. These characters also tend to be [[EnsembleDarkhorse fan favorites]], though this, again, is by no means, necessary. It is not unheard of for TheScrappy to fall under this trope. What’s important here is the reaction of the characters, not of the audience.

Compare and contrast TheHeart, TheCutie, the TagalongKid, {{Moe}}, AndYourLittleDogToo.

Note that this character does not actually have to be anyone’s sister, and a character who is someone’s sister is not guaranteed to fall under this trope.

----
!!Examples
[[foldercontrol]]

[[folder:Anime & Manga]]
* [[ChildProdigy Chiyo-chan]] in ''Manga/AzumangaDaioh'' is a downplayed example; while the series is a SliceOfLife high school story free from major conflict, if Chiyo is threatened in any way, or if she gets mocked by a bully for [[GradeSkipper her age]], the other girls are very quick to protect her. Sakaki in particular has a BigSisterInstinct toward her, using her innate athletic ability to make up for Chiyo's poor performance in P.E. Even Tomo, who's normally TheGadfly, eases off on Chiyo if she feels like she's gone too far in her teasing.
* Casca in ''Manga/{{Berserk}}''. When she's surrounded by enemies, the rest of the Band of the Hawk shows up to rescue her citing the fact that she's the only girl (even though she's the team's second-in-command with only two people able to beat her in combat). Later on, Schierke fits this role (like when Guts starts a BarBrawl when a drunk gets too close to her), as Casca has regressed to a childlike state due to the events of the Eclipse.
* Chilchuck from ''Manga/DeliciousInDungeon''. Despite him being a [[OlderThanTheyLook 29-year-old]] {{Halfling}}, Senshi treats him like a young child, much to his displeasure. At one point, Senshi even tried to teach him about "pistils and stamens", which horrifies Chilchuck no end. [[spoiler:Chilchuck is later revealed to be married, and to have three daughters old enough to be independent, making him one of the most “adult” members of the group.]]
* [[CuteMonsterGirl Nezuko Kamado]] from ''Manga/DemonSlayerKimetsuNoYaiba'' is the younger sister of the main protagonist Tanjiro and the youngest of the four main characters, she's very childlike (due to her transformation to a demon) and is beloved and doted on by much of the main and recurring cast.
* Hikari in ''Anime/DigimonAdventure'' is forced into this position by virtue of being the villain's primary target for her entire introductory arc. Well, besides being TheLeader Taichi's actual baby sister. Afterward, her status as the new kid, MysteriousWaif tendencies, suffering a relapse of the illness that prevented her from main character status in the first place, and then trying not to let on because of her selflessness cement it.
* Wendy in ''Manga/FairyTail'' is among the youngest members of the guild, and, being 12 at the start of the series, is several years younger than most of the current generation, who are roughly 16-18. As a result, she ends up serving this role to the others, particularly the "strongest team" of Natsu, Lucy, Gray and Erza - she says she considers her fellow Dragon Slayer Natsu to be like an older brother and [[AllThereInTheManual in supplemental materials]], the others are said to regard her as a younger sister.
* ''Anime/GhostInTheShellStandAloneComplex'' has Togusa for Section 9. Partly because he's the team's only non-{{Cyborg}} member and partly because he has a family. This can be seen best in the episode "One Angry Man -- TRIAL", where [[spoiler:trying to drag Togusa's name through the mud leads a {{Domestic Abuse}}r and his lawyer to suffer an [[MakeItLookLikeAnAccident unfortunate car accident]].]]
* Alvis in ''Anime/LastExile'' is the LivingMacGuffin whom most of the series revolves around the other characters keeping away from the Guild. She's also a cute little girl that does cute things cutely, so she tends to inspire everyone to be protective and caring towards her beyond that.
* Chopper in ''Manga/OnePiece'' is the youngest out of the Straw Hats and is the resident little brother, especially for the male crew members such as Zoro and Sanji, who looks after him and gives him advice and guidance.
* Haruhi from ''Manga/OuranHighSchoolHostClub'' can be this to the members of the host club. While some of them actually have crushes on her and act out of jealousy, Haruhi is still a first-year (one of the youngest members) and all the guys are willing to go above and beyond to protect her at even the slightest inkling that she's in danger.
* Bonnie from ''Anime/PokemonTheSeriesXY'' is Clemont's little sister, and his BigBrotherInstinct is combined with similar protective feeling from Ash, Serena, and their Pokémon.
* ''Anime/TamaAndFriends'' has the little kitten, Koma. Being the youngest and smallest among her cat and dog friends, everyone in Tama's group see her as their little sister.
* ''Manga/YuGiOh'' has Shizuka and Mokuba, both around thirteen years old and are constantly protected by the older members of the gang.
[[/folder]]

[[folder:Comic Books]]
* ''ComicBook/BlackCanary'': Among the Justice Society of America, she had something similar to the above prior to their reformation, as most of them have known her since she was born, so they see her as their niece. In ''JLA: Year One'', her status as the only girl on the team and her youth (she was 19 at the time, while the others appeared to be in their 30s by comparison) lead to this, something she was ''vocally'' annoyed with as she frequently told them off for treating her like a damsel they had to protect. In ''ComicBook/BirdsOfPrey'', though the UndyingLoyalty goes both ways, Dinah being in danger seems to strike the biggest reaction from the others.
* ''ComicBook/JusticeSocietyOfAmerica'': The JSA have done this since being revived in TheNineties, and retooled so that, rather than simply be [[UsefulNotes/TheGoldenAgeOfComicBooks the Golden Age]]'s primary team of heroes, the remaining members act as mentors and teachers to the [[LegacyCharacter legacies, proteges, and descendants]] of the original team and/or heroes they were friends with. Though they've had a few characters who fulfil the role, the original was [[Franchise/TheFlash Jesse Quick]], while the most prominent and popular was [[ComicBook/StarsAndSTRIPE Stargirl]], whom pretty much everyone sees as either a surrogate daughter or a kid sister. She seems aware of this and is often ''annoyed'' by it.
* ''ComicBook/{{Nightwing}}'': Dick Grayson began as ComicBook/{{Batman}}'s KidSidekick, which in contemporary continuity was between 10-15 years ago. This makes him one of the most known superheroes in the world despite his relatively young age, and one that [[SoProudOfYou all of his older colleagues]] are ''very'' proud of to see grown into a [[NiceGuy fine young hero]]. Thus, if Dick calls on any other superhero for help, they will usually come running. These same older heroes (and some {{antivillain}}s, like ComicBook/{{Catwoman}}) will ''rain down the hurt'' on anyone who dares to harm Nightwing. ''[[PapaWolf Especially Batman]]''. In his solo series, this has saved his life more than once, as small-time villains who had defeated Nightwing in combat deliberately let him live because they knew that wasn't the kind of heat that they wanted to bring upon themselves.
* ''ComicBook/RelativeHeroes'': Aviva Weinberg is literally the baby sister of her team as it's made up of her siblings. When the Weinbergs help with the invasion of Zandia several members of ComicBook/YoungJustice and their allies make sure to keep her out of the line of fire or at least behind forcefields and bulletproof individuals since she is incredibly young for a superhero, even when compared to the rest of the group which is almost entirely made up of teenagers.
* ''ComicBook/{{Runaways}}'': Molly and Klara fill this role, to varying degrees -- Molly is ''everyone's'' baby sister, but Klara is more of a little sister to Nico and Karolina, while Chase and Victor treat her more like TheLadette. Oddly enough, the "baby sister" aura even seems to affect other people in the Marvel universe -- for instance, during ''ComicBook/SecretInvasion2008'', Speed of the ComicBook/YoungAvengers literally went out of his way to keep Molly and Klara safe during a battle with the Skrulls.
* ''ComicBook/SecretAvengers'': Volume 2 seems to play [[Characters/MockingbirdMarvelComics Mockingbird]] like this during the "[[BreakTheHaughty How to Maim a Mockingbird]]" arc. ComicBook/{{Hawkeye}}, her ex-husband, is visibly torn up from seeing what happened to her during the arc, ComicBook/BlackWidow stops joking and talks to her the way that a worried sister would when she realizes the seriousness of the situation, and [[Characters/IronManHeroes War Machine]] actually ''quits the team'' in protest and disgust at the fact that [[Characters/SHIELDDirectors Maria Hill]] allowed Mockingbird to get into such a situation (and is joined with Hawkeye in this), while Maria Hill herself is clearly not happy with herself for allowing this to happen and makes a promise to find her. Even ''[[Characters/MarvelComicsTaskmaster Taskmaster]]'', the TokenEvilTeammate, is pretty shocked to see how broken she is and is clearly concerned for her welfare.
* ''ComicBook/XMen'':
** [[Characters/MarvelComicsKittyPryde Kitty Pryde]], who might be the closest to an AlternateCompanyEquivalent to Nightwing in this respect. She joined the X-Men when she was 13 as a rookie, and unlike the ComicBook/NewMutants, whom were her age but joined after, she trained directly with the main team and was close with each one.
** The X-Men actually made a trend of this, starting even before Kitty joined. In the original line-up, [[Characters/MarvelComicsJeanGrey Jean Grey]] was the token female member of the team and had the weakest power, which prompted the boys to alternate between being protective big brother-like figures and being infatuated co-eds, and as they got older all but [[Characters/MarvelComicsCyclops Cyclops]] grew to see her as their sister (Scott was the exception because instead, the two fell in love). After Jean was Kitty, then after Kitty, [[Characters/MarvelComicsJubilee Jubilee]] joined and took on a similar role, followed then by [[Characters/NewXMenAcademyX Pixie]] fulfilling a similar role later.
[[/folder]]

[[folder:Fan Works]]
* ''Fanfic/ChildOfTheStorm'':
** [[Characters/ChildOfTheStormHarryThorson Harry]] is treated as this by most of the adults in the cast, Avengers and associates especially, for most of the first two books, because he's thirteen, more than a tad traumatised, and related to a fair chunk of them. He's less bothered by it than you might think, because he grew up without ''any'' real family.
** As Harry becomes more worldly, powerful, and capable of looking after himself, Peter Parker starts to fall into this role in part because he's TheCutie, and in Book III, so does [[spoiler: Francis Richards]].
* {{Deconstruct|ion}}ed in ''Fanfic/ForHisOwnSake''. While Shinobu ''seems'' to have this status among the Hinata Girls, her self-assigned protectors Naru and Motoko primarily use her as an excuse to deliver {{Unprovoked Pervert Payback}}s upon [[ButtMonkey Keitaro]], as they insist AllMenArePerverts and constantly falsely accuse him of making untoward advances upon her. Keitaro [[TheResenter comes to resent]] how Shinobu is too much of an ExtremeDoormat to call them out on this, seeing her as an AccompliceByInaction. And when Shinobu ''does'' [[GrewASpine start standing up for herself]], Naru and Motoko [[FairWeatherFriend instantly turn upon her]]. Shinobu realized that the girls never really liked her; they just expected her to be a yes-man who agreed with everything they said and used her as an excuse to abuse Keitaro under the guise of protecting her. Shinobu decides to unfriend the girls and call them out on their actions, move in with her aunt, and work on repairing her friendship with Keitaro, whom she apologizes to and promises to stand up for him from now on. By the end of the story, Shinobu becomes a stronger and more assertive person who is ready to stand up for her friends like Keitaro; she repairs her friendship with Keitaro, who forgives her because of her apology and shows that she has learned from her mistake by standing up for him. She even repaired her relationship with the girls who realized they were wrong and were willing to change while standing up to the girls who were unwilling to change and remained toxic and horrible.
* In ''Fanfic/IncarnationOfLegends'', Bell's young age, sincerity and sweetness elicit protective feelings from both the Hestia Familia and Astraea Familia. The normally cold and pragmatic Kaguya instantly leaps to Bell's defense when Bete mocks him as the weakling who ran in terror when Aiz showed up, drinking Bete under the table in the process.
* ''Fanfic/InfinityTrainSeekerOfCrocus'': Lampetia is a [[LivingStatue kouros]] -- a marble statue in the shape of a woman -- but she's treated as such by White Gestalt (whose eldest member is nearing 40 and their youngest is 10) due to her innocence, cheerful nature and that the last time White Gestalt was on the Train, she died (but got better) which lead to ''everyone'' losing their innocence over the nature of it. Saying any ill will about her, or trying to harm her is basically the equivalent of a death sentence.
* ''Fanfic/ThisIsAWildGameOfSurvival'': Mostly to Ha-ri, his actual older sibling, but Woo-jin qualifies as this. Ha-ri has been overprotective of him since the moment their parents brought him home from the hospital as babies. Joon-yeong falls in love with him immediately after meeting him and can be protective of him, particularly when comforting him after Ha-ri finds out about their relationship and in feeling responsible for Woo-jin breaking his wrist and nearly getting killed. Dae-su also promises to kick the ass of anyone who hurts him, be it homophobia or Joon-yeong breaking his heart. Tellingly, every one of the classmates present to hear the bastard soldier insult Woo-jin for grieving is pissed off enough to throw peaches at the soldier.
[[/folder]]

[[folder:Films -- Live-Action]]
* [[MeaningfulName Cheedo the Fragile]] in ''Film/MadMaxFuryRoad'' is the youngest of Immortan Joe's [[SexSlave unwilling Wives]] and, as of the time of the film, the only one who hasn't already been raped by him due to being [[BreedingSlave too young to breed]], so the other Wives are extremely protective of her and try to shelter her from Joe's true monstrosity, which results in UsefulNotes/StockholmSyndrome where Cheedo at one point attempts to turn herself into Joe while on the run. The prequel comic also shows that The Dag went so far as to directly interfere when Joe tried to rape Cheedo, and was savagely beaten for it, causing Cheedo to blame herself.
[[/folder]]

[[folder:Live-Action TV]]
* ''Series/AgentsOfSHIELD'': Leo Fitz and Jemma Simmons both qualify as this trope. The other characters' reactions to their lives being endangered in [[ContaminationSituation "F.Z.Z.T."]] and "Beginning of the End" exceed what we've learned to expect when Coulson, May, Ward, and Skye risk their lives. Fitz and Simmons are the non-field agents on the team, and two of the youngest. In "F.Z.Z.T.":
-->'''May:''' ''(of Simmons)'' She's only a kid.
* ''Series/{{Arrow}}'': Despite Oliver Queen having a genuine little sister (Thea, whom he'll go to [[KnightTemplarBigBrother extreme lengths to protect]]), this role goes to Felicity Smoak instead (even after Thea joins them). She's the only non-combatant on TheTeam, and Ollie and Diggle in particular go to great lengths to ensure her safety and keep her hands clean.
* On a meta level, Willow from ''Series/BuffyTheVampireSlayer'' - the writers quickly discovered that threatening her was one of the best ways to get the audience to react. An aphorism among the writing staff was "When in doubt, put Willow in danger". As Willow grows more worldly in later seasons this role was taken over by Buffy's literal little sister Dawn, the Scoobies falling over one another to give their lives to protect her from Glory and other threats.
* ''Series/{{Community}}'': As the youngest member of the study group, Annie Edison gets treated this way a lot, especially in early seasons (in later seasons she mostly proves that [[WiseBeyondTheirYears she's more mature than the rest of them]]). This causes friction with her primary love interest, Jeff, who is sixteen years older than her. Early on, he repeatedly uses her age as an excuse not to date her. In later seasons that excuse mostly disappears, and Jeff's self-loathing is the main thing that keeps them apart.
* ''Series/DarkMatter2015'': Five, as a sixteen-year-old and the only non-criminal member of the crew, tends to be kept on the ship for her own safety most of the time, despite the fact that her [[TeenGenius technical expertise]] is extremely useful on the rare occasion she ends up on a mission. This creates the odd dichotomy that the crew both know how competent Five is but still treat her as younger than she really is. In "Wish I'd Spaced You When I Had the Chance," when Five gets kidnapped, Three asks around for the [[TagalongKid "kid"]] he was with. A local who saw her get taken is bewildered, because while she's young, she's also clearly not a child. Also, threatening or hurting Five is a good way to make the entire crew [[BigBrotherInstinct want to kill you]].
* ''Series/{{Firefly}}'': Most of the time, when a crew member gets injured, it gets more or less shrugged off. When Kaylee gets shot in the pilot, it's a different story. Mal threatens to [[ThrownOutTheAirlock toss Simon into space if he fails to save her.]] Jayne, who rarely shows concern for anyone, immediately goes after the man who pulled the trigger.
-->'''Book:''' You're not going to kill this man.\\
'''Jayne:''' Well, [[ColdBloodedTorture not right away]].
* On ''Series/GeneralHospital'', Robin was this to everyone in town. The trope was so deeply in place that when Carly came to town, the first indication that she was going to be a villainous-type was that not only did she dislike Robin, she couldn't understand why everyone else adored her.
* On ''Series/GuidingLight'', Abby (who was already this to the townspeople) was attacked and nearly raped by a gang member. When the rest of the gang began making threats to her in the hopes of preventing her from testifying, the TokenGoodTeammate (a) reminded them of what he'd done, clearly trying to invoke EvenEvilHasStandards, and (b) informed them that, "You know who she looks like? Tony's (gang member's) sister. Might as well have been ''her'' he tried to mess with."
** Lucy Cooper falls into this role also, literally being this in the Cooper family.
* ''Series/KamenRiderExAid'': Emu Hojo's [[AllLovingHero kind]], [[IncorruptiblePurePureness optimistic]] nature tends to incite BigBrotherInstinct in people around him. [[GoodIsNotSoft He]] is a capable [[TheChessmaster strategist]] and [[BatmanGambit manipulator]], but most of all, he wears his ideals and heart in the open, which makes him an easy [[BreakTheCutie target]]. The [[DysfunctionJunction CR Crew]] will readily drop fighting with each other to help him.
** Nico is the youngest member of the crew and also keeps on inserting herself into dangerous situation despite being the only civilian on a team of Kamen Riders. Also, she hates to be babied, but does not help matters by being a [[BrattyHalfPint Bratty Half Pint]] [[PintSizedPowerhouse Powerhouse]].
* ''Series/KamenRiderBuild'': Everyone in Nascita family dotes over Misora, the band's young NightmareFuelStationAttendant, in some way. Granted, [[AbhorrentAdmirer Kazumi]] is inevitably a creep about it, but he cares too. They try their best to shield her from both the [[CosmicHorrorStory supernatural]] and [[WarIsHell mundane]] horrors going on outside, but it's mostly pointless. She knows and is most hurt by them trying to keep secrets from her. Nothing can stop her from trying to help them, but nothing will stop them from trying to keep her away from battle either.
* ''Franchise/LawAndOrder'':
** This tends to happen with the Assistant District Attorneys. We've only really seen it played out with Claire Kincaid and Alexandra Borgia on the original ''Series/LawAndOrder'' and Alex Cabot on ''Series/LawAndOrderSVU'', but it did play out with all three of them.
** On ''Series/LawAndOrderUK'' with junior CP Alesha Phillips. The reactions from the rest of the team when she's raped make it obvious that harming her is a bad idea.
* On ''Series/{{NCIS}}'', the best way to make something personal for the entire team is to threaten Abby Sciuto. This can be seen when you compare an episode like "Bloodbath", where someone is after Abby, to episodes like "Frame Up", "Reveille", "Probie", and "Recoil", where the threats against Tony, Kate, [=McGee=], and Ziva are taken seriously, but not as personally.
** Newcomer Ellie Bishop appears to be falling into this role too; everyone has taken her under their wing to some extent, and they've all expressed a desire to beat the tar out of her adulterous husband. When her three ''actual'' older brothers show up, they take the trope to its logical extreme.
* On ''Series/OnceUponATime'', Henry is the only character who could have gotten Emma, Snow, Charming, Regina, Rumplestiltskin, and Hook [[spoiler:on a ship to Neverland together]]. This may be a factor of [[TagalongKid his age]] and the fact that he's [[TangledFamilyTree related to almost the entire main cast]].
* ''Series/SamuraiSentaiShinkenger'': Kotoha Hanaori might perceive herself as TheLoad despite her best efforts to improve but the rest of the team digress. She simply doesn't have as much trainning as the rest of them (minus [[ClassClown Chiaki]]). If she is in a serious danger, they will drop everything to save her.
** Mostly averted with Chiaki Tani, who ties with Kotoha as the least experienced team member, but unlike her is an annoying goof with an attitude problem, so he naturally invokes somewhat less protective feelings from the rest of the team.
[[/folder]]

[[folder:Video Games]]
* Merrill from ''VideoGame/DragonAgeII'' is this to most of the party. Only Fenris and Anders dislike her due to her use of BloodMagic.
** In a non-mage-Hawke playthrough, Bethany - who is Hawke's actual little sister - also qualifies whenever she's present. ''Everyone'' in the party likes her, including the staunchly anti-mage Fenris; Anders is lukewarm at worst. [[spoiler:If she goes to the Circle instead of dying or joining the Grey Wardens, this trope remains in effect even after Act 1.]]
* Phym in ''VideoGame/GodEater3'' immediately becomes the darling of everyone in Chrysanthemum after she is rescued by the Protagonist from an attacking Anubis, and she is especially held dear by the Protagonist (who is her ParentalSubstitute) and Claire (who the narrative treats as her CoolBigSis most of the time). [[spoiler:When she is forcibly taken away by Dr. Inukai midway through the game, the Hounds immediately devise a plan to rescue her even if it means going against Gleipnir, and in the final part of the main story they even go against an Ash Tempest-corrupted Odin unit she is trapped in after she turned herself in to Gleipnir's command to prevent other [=AGEs=] from being used to power the Odin units.]]
* ''VideoGame/GuardianTales'': The Little Princess, the [[TheHero Knight's]] adventure companion. All of the heroes of Heavenhold treat her like she was their youngest sister rather than a [[AuthorityInNameOnly royal princess]], and [[ModestRoyalty she prefers to be treated as such]]. That doesn't mean she hasn't seen her fair share of [[PintSizedPowerhouse shining]] [[RoyalsWhoActuallyDoSomething moments]] though, examples being her fighting Invaders with just a baseball bat, [[spoiler:sneak attacking an evil version of her Knight, although [[KickTheDog she gets thrown off their back towards a wall afterwards]], rendering her unconscious for a while]], and [[spoiler:reversing the effects of a bio-weapon that had just detonated and killed everyone in the area, albeit unconsciously]]. In addition, [[spoiler:in an alternate timeline where the Knight suddenly disappears, as rumors of [[WhatTheHellHero the Knight abandoning their duty]] begin to circulate, she becomes [[DespairEventHorizon overcome with despair due to all the deaths happening around her that could've been prevented]], and she begins taking combat and leadership lessons in hopes of becoming the world's new hope, becoming the [[FutureBadass Future]] [[TookALevelInCynic Princess]] over the course of ten years.]]
* In ''VideoGame/{{Omori}}'', Sunny is considered the baby of the group due to him being the youngest.
* ''Franchise/{{Persona}}'':
** ''VideoGame/Persona4'': Nanako Dojima, [[TheHero protagonist Yu Narukami's]] little cousin and the Justice Arcana. She's a surprisingly mature and diligent young girl who masks how terribly lonely she is since her mother died and her father, the protagonist's uncle and a police officer, dove into his work as a response. The protagonist quickly becomes the older brother she never had and his [[TrueCompanions friends, the Investigation Team]] quickly come to view her in the same light as well because of her kindness and empathizing with her. [[spoiler: When she seemingly dies in the hospital from exposure to the TV World, [[RoaringRampageOfRevenge the team quite nearly lose it and seek to kill the one responsible]]. However, if you let them do this, this leads to a bad ending since he's not the true murderer. The good ending has the protagonist stop them when he realizes something's up. Your reward for this is her managing to make a full recovery, reducing the team to TearsOfJoy]].
*** Lampshaded in the FightingGame sequel, ''VideoGame/Persona4Arena'', as the protagonist's title is "The Sister Complex Kingpin of Steel", with the caption, "''Nobody'' touches his precious Nanako!"
** In ''VideoGame/Persona5'', Futaba appears to play a similar role, despite being older than Nanako (she's two years younger than Makoto and Haru, and one year younger than everyone else in the party). After saving Futaba from committing suicide by destroying the manifestation of her guilt over her mother's death, the rest of the Phantom Thieves bond with her, helping her to come out and see others, and eventually take her to the beach with them. During one randomly occurring exchange, while exploring Mementos, Makoto points out that seeing someone as cute as Futaba reminds her of the time when she wanted a younger sister.
*** The new playable character [[TokenMiniMoe Sophia]] in ''VideoGame/Persona5Strikers'' being both the newest Phantom Thief and an [[ArtificialIntelligence AI]] with little knowledge of but an earnest desire to learn about humanity, Sophia becomes this to the rest of the Thieves, who are extremely protective and supportive of her and her endeavors to learn about herself and human hearts. They do not take it kindly AT ALL (especially Ryuji) when the voice in the Okinawa Jail [[spoiler:and Sophia's own creator Kuon Ichinose]] insult and declare her existence a mistake and meaningless.
* Sachi from ''VideoGame/{{Raramagi}}'', one of the youngest members of Music Club, is [[https://cdn.img-conv.gamerch.com/img.gamerch.com/raramagi/260985/20170305002627gnKFsBf7.jpg doted on]] by almost every older member of the club. Combined with her being a sweet NiceGirl and [[ChildrenAreInnocent innocent to the core]], it's easy to see why everyone adores her. It becomes a plot point when she starts to act out of character due to Noise interfering during later chapters.
* Sheva Alomar of ''VideoGame/ResidentEvil5'' is described as the "little sister" of her BSAA squad by her C.O. and mentor, being the youngest and greenest member. Of course, Chris Redfield is told of this long after she's ably demonstrated her own competence and badassery, and his survival depends on her throughout the mission as much as hers depends on him.
* In ''VideoGame/{{Rosenkreuzstilette}}'', it is revealed in the final confrontation with BigBad Count Michael Zeppelin that the action which triggered the RKS rebellion against the Holy Empire was [[spoiler:Kahl Palesch]] attempting to assassinate the count's young and innocent daughter Iris. This energized him and the members of RKS, who treat Iris like a little sister, to fight back and stop the resurface of Magi persecution. [[spoiler:And then it turns out that Iris ''invoked'' the trope so as to spark a war [[ItAmusedMe for her amusement]] and as part of a plan to [[GodhoodSeeker ascend to godhood]].]]
* ''VideoGame/StellaGlow'': Marie, an amnesiac little girl [[TheHero Alto]] found and took under the 9th Regiment's care, quickly becomes the emotional support to everyone in the Regiment, helping to lift everyone's spirits when they're down. Everybody on the team likes her and become extremely protective of her. Even Queen Anastasia likes her, comparing her to the little sister she never had and was considering adopting her as one. [[spoiler:When [[TheHeavy Xeno]] takes her away in the endgame, the heroes are devastated, but quickly become determined to save once they're motivated.]]
* ''VideoGame/WatchDogs2'': The entire [=DeadSec=] Team is fiercely protective of Josh, a young man with high-functioning autism that joined them to fight back against Blume after [=CtOS=] ruined his life by branding him as unemployable.
[[/folder]]

[[folder:Visual Novels]]
* This is not an uncommon trope in otome games (dating games aimed at mainly heterosexual women.) Since the protagonist in these games is typically female and the player determines who she gets together with, all the dateable men (and even some dateable/friendship route women)like the main character and become fairly protective of her. This, in turn, means that any time a bad guy [[TooDumbToLive messes with the protagonist]] you can be sure one of, if not all of, the dateable characters will come after them, invoking this trope. This is particularly true in games like VisualNovel/CodeRealize and London Detective Mysteria.
* In ''VisualNovel/CafeEnchante'', Kotone is the youngest and most vulnerable out of the main cast. Regardless of the romance route, all the regulars are fiercely protective of her and anyone threatening or hurting her is a sure way to get several powerful beings pissed off.
* In ''VisualNovel/{{Nightshade}}'', out of the group of friends, Kasumi is the most innocent and child-like, even though she is only a year younger than the sixteen year old Enju, and all of them act as her older siblings.
* In ''VisualNovel/SpiritHunterNG'', everyone that Ami talks to has a soft spot for her, and her kidnapping by Kakuya is treated as unforgivable both by her cousin-turned-brother and his friends. Kaoru thinks she could become a good idol because she triggers a protective instinct in others.
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[[folder:Web Comics]]
* ''Webcomic/CursedPrincessClub'': Gwendolyn is this for the Cursed Princess Club, both because they want to make their newest member feel welcome and because her sweet, nonconfrontational personality and intense AppearanceAngst make them eager to help her overcome her insecurities. At certain points, they even express a desire to give Prince Frederick, Gwen's unwilling fiancé who called her ugly and thus gave her those insecurities, a piece of their minds. [[spoiler:That desire becomes inconvenient when Frederick eventually stumbles upon the club (which they actively keep secret from non-members). They initially try to drug him to sleep to make him think his encounter with them was just a dream, and when that fails they come close to giving him a NoHoldsBarredBeatdown while angrily berating him for how he has treated Gwen. But they soon find out that Frederick has come to be genuinely attracted to Gwendolyn by that point, making them realize they were overreacting. The CPC members ''do'' later get a chance to satisfy their protective instincts when Frederick's childhood bullies gear up for tormenting Frederick and Gwendolyn, and the CPC teams up with [[BigBrotherInstinct Fred's older brothers]] to scare the bullies out of their wits.]]
* In ''Webcomic/DarthsAndDroids'', Ben's little sister Sally is initially brought to the group because he's forced to babysit her, but she quickly gets integrated into the game as Jar Jar Binks (and single-handedly [[RescuedFromTheScrappyHeap makes the character enjoyable]].) In the early strips when she was young, the GM and players tended to be protective of her, cheering her on and giving her extra chances at failed dice rolls.
* In ''Webcomic/ErrantStory'', Misa is this, ''very'' much against her will: she desperately [[IJustWantToBeBadass wants]] to go out and have adventures like her idol Sarine, but because she's the youngest of all the pure-blood elves[[note]](relatively speaking, she's "only" 1400 years old)[[/note]] and is considered to be of near-miraculous origins, the elves won't let her, even during their final, species-threatening battle. Finally averted, however, when at a key stage of the battle, Sarine herself starts treating her like a grown-up.
* Mob of ''Webcomic/MobPsycho100'' becomes one for the Body Improvement Club, which cheers on his attempts to keep up with their rigorous workout routines and will rally to his defense without a second thought. The knowledge that he's an insanely powerful {{Psychic Child|ren}} appears to have no ruling on this. [[JapaneseDelinquents Onigawara]] even weaponizes the club's protective tendencies by tricking a rival gang at Black Vinegar Middle School into taking him hostage, bringing the Body Improvement Club's wrath down on them.
* This is part and parcel of Piffany's IncorruptiblePurePureness in ''Webcomic/{{Nodwick}}''. For all that Artax and Yeager engage in ComedicSociopathy on ''many'' others, they will not tolerate anyone being mean to her. Their LetsGetDangerous cry is "He/She/They made Piffany cry!"
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[[folder:Web Original]]
* ''Website/SCPFoundation'': [[http://www.scp-wiki.net/scp-085 SCP-085]], "Cassie," is a living 2D drawing of a young woman who thought she was living a reasonably productive life in a post-apocalyptic wasteland until she found out the truth behind her situation. The Foundation as a whole feels pretty bad about everything that's happened to her, partly because she only exists because they were playing around with some other [=SCPs=]. A lot of effort is made to make her feel comfortable, from finding things she can use in her 2D state to discussing getting her a psychiatrist.
* In ''WebAnimation/RedVsBlue'', Michael J. Caboose serves this role over time. Even when the [[FriendlyEnemy "opposing" teams]] are insulting one another, they make time to be nice to him, and actually make an effort to make sure he feels good about himself. The times when he is upset by an outside party are actually treated as deadly serious and horrible things to do, especially by [[BigBrotherInstinct Tucker]].
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[[folder:Western Animation]]
* ''WesternAnimation/CaptainPlanetAndThePlaneteers'': The Planeteers [[{{Protectorate}} hate seeing villains mess with members of the team]], but [[CheerfulChild Ma-Ti]], being the youngest and most innocent, amplifies that protective instinct.
* A 'baby brother' example, in ''WesternAnimation/SonicTheHedgehogSatAM'', Tails is one of the main targets for Robotnik to grab, mostly due to a) his age, and b), his little brother relationship to Sonic. (If it's not Tails, [[TomboyPrincess Sally]] is who Robotnik will nab, being [[TheHero Sonic's]] {{love interest}} and all.)
* ''WesternAnimation/StarWarsTheBadBatch'' has Omega, the newest addition to TheSquad. For one thing, she's literally their baby sister, being the only female clone of Jango Fett as well as the only one who's not fully mature. For another thing, she's the only one who's not trained for combat and is therefore the least prepared to fight against the threats they face. Throw in the fact that she's being targeted by bounty hunter Fennec Shand, and it's a given that [[BigBrotherInstinct her big brothers will be coming to her rescue]]. It later turns out she was the ''first'' to be cloned but, like her brother Boba Fett, ages naturally.
* [[Characters/StevenUniverseStevenQuartzUniverse Steven Quartz Universe]] from ''WesternAnimation/StevenUniverse''. The Crystal Gems are his {{Parental Substitute}}s since his mom, their former leader, suffered the supernatural equivalent of DeathByChildbirth. His [[AllLovingHero personality]] also gets him "little brother" status with every teenager in Beach City, [[MyFriendsAndZoidberg except]] [[JerkWithAHeartOfGold Lars]] (not that this dissuades Steven from trying). As of Season 5, even Lars has warmed up to Steven.
** Padparadscha seems to be this for the Off-Colors. Lars, a self-admitted DirtyCoward even takes on the robloids to protect her and Rhodonite is quick to guard Padparadscha as well. A good part of this, beyond her size, is that Padparadscha is a "flawed" Sapphire. In Gem society, Sapphires serve as advisers because of their ability to see into the future. However, Padparadscha's visions are retroactive, meaning she is usually not aware of the danger until after it's been resolved.
* Invoked by Hun in the 2003 ''WesternAnimation/{{Teenage Mutant Ninja Turtles|2003}}'' cartoon, in which April is a mix of little sister and [[CoolBigSis big sister]] to the turtles (she even acts as [[TeamMom a motherly figure]] sometimes):
-->'''Hun''': Those green freaks feel great affection for you. Losing you should take the fight out of them.
* Season 7 of ''WesternAnimation/VoltronLegendaryDefender'' shows that Pidge is a [[DownplayedTrope mild version]] of this. She was already the youngest Paladin, and Zethrid and Ezor correctly assume that the rest of the team would be the most angry if they attack her as opposed to anyone else. Lance in particular immediately proves them right by charging at them and trying to fight them for it.
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