You have a younger sibling. Either full-blooded, half-blooded, or just adoptive (or, in some odd cases, more than one of those at once). Especially a little sister. The kid is wronged somehow. What do you do?

Do you deal with the offender in a calm, civil manner?

Or failing that, perhaps you are a little upset, yet you keep control over your emotions, and keep yourself as restrained as you can?

Or do you go after the offender, the offender's friends, anyone connected to the offender, as well as anyone who even looks like they could be an offender sometime in the indeterminate future and kill them all in as painful a manner as possible?

If you are the latter, then congratulations! You are officially a Knight Templar Big Brother (or Knight Templar Big Sister).

This trope is what happens when a character takes the BigBrotherInstinct to the extreme. They don't just protect the younger sibling, they absolutely destroy anyone who'd so much as even look at them wrong. Much like the KnightTemplar and KnightTemplarParent, the Knight Templar Big Brother often genuinely believes that what they are doing is right and fully beneficial to the younger sibling, [[WhatTheHellHero which often results in a clash of siblings later on within the show or work.]]

Contrast with SpartanSibling

See also: BigBrotherInstinct, KnightTemplar, KnightTemplarParent, MySisterIsOffLimits. If the characters aren't actual siblings, it probably is {{Yandere}}.
----
!!Examples:

[[foldercontrol]]

[[folder:Anime and Manga]]
* ''Manga/AttackOnTitan'':
** Mikasa Ackermann towards her adoptive brother Eren Yeager. She's violently over-protective, to the extent that she will ignore direct orders or the greater good (such as helping evacuate citizens) to protect him. On numerous occasions, she's threatened the lives of even her TrueCompanions, making it clear if forced to choose between Eren's well-being and their lives, she will kill them without hesitation.
** Levi was one to his [[DoomedByCanon ill-fated]] surrogate little sister, Isabel, in the SpinOff prequel about his past. When she came home beaten up and [[TraumaticHaircut missing a pigtail]], he went out. He comes home that evening, cleaning blood off a knife and won't answer when Farlan asks if he killed those responsible.
* Lelouch Lamperouge from ''Anime/CodeGeass''. After his younger sister Nunally was wounded in a terrorist attack (that also killed their mother), he started a war and took over the world, all for her sake. [[spoiler: And when she found out, [[WhatTheHellHero she got]] ''[[WhatTheHellHero pissed]]''.]]
** In Season 1 Mao, a StalkerWithACrush to Lelouch's partner C.C, kidnapped poor Nunnally and strapped a bomb to her. Lelouch was ''already'' very pissed off at Mao, since he first [[spoiler: {{Mind Rape}}d his poor, sweet classmate -- and a total innocent bystander which he had no business to involve -- Shirley]] and then did the same to [[spoiler: his ForgottenChildhoodFriend Suzaku]]; needless to say, Mao did ''not'' meet a pleasing end.
--> '''Lelouch''': [[spoiler:[[CompellingVoice MAO]]! [[ShutUpHannibal NEVER SPEAK AGAIN]]!]]
* ''Manga/{{Bleach}}'' has a few examples:
** Ichigo adamantly believes the reason a big brother is born first is to protect all the little siblings that follow. He will force-feed this belief by the sword if he has to to any big brother he catches not protecting their own siblings, as both Orihime and Rukia's respective big brothers discover. And when he feels [[spoiler:his own sisters are threatened and murder is the first thing '''he''' comes up with. And when Yuzu dies in fourth movie, due to being exposed to hell miasma for too long, he uttery flips out, goes into his super Hollow form and destroys Hell.]]
** Once he manages to resolve his conflicting vows, Byakuya goes from being an AloofBigBrother to a Knight Templar Big Brother where his little sister, Rukia, is concerned.
** Toshiro Hitsugaya and Momo Hinamori have been raised together (the character book of Souls also confirms their relationship is "familial" and the old woman who raised them is regarded by both as their grandmother). He is incredibly protective of her despite being the younger of the two to the point where he attacked a perceived threat to her with such force two nearby vice-captains were caught up in the power he unleashed (one of which was actually her). In the end, their relationship is exploited by the BigBad in one of the biggest KickTheDog moments in the entire manga, the consequences of which is him making a [[ThePromise vow]] to become strong enough to protect her from everything.
* Henry Wong from ''Anime/DigimonTamers'' went from being the most rational and calm guy in the group to being temperamental, hasty and reckless when his sister ends up in the Digital World.
* Both Keiichi Maebara and later, [[spoiler:Shion Sonozaki]], from ''VisualNovel/HigurashiNoNakuKoroNi'' fall prey to this syndrome when their non-blood-related "sister", little Satoko Houjou, is {{abus|iveParents}}ed [[EvilUncle by her uncle]]. Winds up leading to two of the most tragic endings of the series.
** It is heavily implied that her [[spoiler:actual brother, Satoshi]] did the same regarding the [[AbusiveParents aunt]].
* Caren, the AloofAlly of ''Manga/MermaidMelodyPichiPichiPitch'', starts dangerously close to this, having been perfectly fine until her twin sister was kidnapped. However, while she blames and berates the good guys as well as the bad, she does do a lot of [[IWasJustPassingThrough reluctant rescues]] and admits that she was wrong instead of going off the deep end.
* Another Knight Templar ''Younger'' Brother is [[spoiler: Fire God Apollo]] from ''Manga/{{Cyborg 009}}'', towards his older sister [[spoiler: Hunt Goddess Artemis]]. When [[spoiler: the girl died [[TearJerker very tragically]], the already unstable Apollo went literally ''insane'' with grief and killed the culprit, then let himself die whispering his sister's name]].
* Ran Fujimiya in ''Anime/WeissKreuz'' is downright obsessively protective of his IllGirl little sister Aya. He became an assassin in large part to pay her medical bills (she's in a coma), and he is not in the least bit rational about threats to her safety.
* ''Manga/{{Naruto}}'':
** Kankuro becomes one of these as a part of his CharacterDevelopment, reacting violently to anyone who badmouths his little brother Gaara in front of him and going after Gaara alone after [[MadArtist Deidara]] and Sasori of Akatsuki kidnap him and Kankuro's team mates are nearly all killed in an explosion. Given that Gaara used to be an AxCrazy psychopath who regularly threatened to kill Kankuro, this is quite a drastic change. Sadly, it all goes horribly wrong when poor Kankuro gets his arse handed to him by Sasori, and Sakura barely manages to save him.
** There's also the Raikage. When he is told his brother Killer Bee was killed by Akatsuki his response was to call an international meeting to stop Akatsuki. When he found Sasuke he became so hellbent on revenge that he didn't even care if he [[spoiler:lost his arm]] to kill him. And [[spoiler:his leg]], too, if Gaara hadn't stopped him. It's also possible that, despite all that, if Gaara hadn't stopped him, Sasuke would have ''died.''
** Possibly one of the most well-known examples is [[spoiler:Itachi Uchiha]] towards [[spoiler:Sasuke ''and'' the Leaf Village.]] The whole Uchiha Massacre episode was set up to [[spoiler:protect Konoha from the coup d'etat his own father was planning, and though he was able to kill both of his parents, his best friend, ''and'' his girlfriend, he couldn't bring himself to kill Sasuke]]. He even went so far as to threaten to ''leak the village's information to every rival village'' if [[spoiler:Sasuke was ever hurt due to something the leaders of Konoha had done or ordered]]. Let's not even discuss the deal with their fight to the death or the fact that [[spoiler:Itachi let Naruto get away from him after said IdiotHero promised to straighten the then-rogue Sasuke out]]. And after what happened to Madara when Sasuke [[spoiler:saw his Sharingan...]] let's just say it's rather [[AndIMustScream frightening]] to imagine the exact consequences of someone doing anything to [[spoiler:permanently injure Sasuke.]]
** Neji Hyuga becomes this for Hinata in ''Manga/RockLeesSpringtimeOfYouth'', where he beats up and kicks everyone who wrongs Hinata. He mostly does it to Naruto, because Naruto obliviously says inappropriate things to Hinata, which leads to Neji beating the crap out of Naruto. There is also this instance where Hinata timidly approaches Naruto, Neji and Lee. Neji tells Naruto and Lee to be patient with her and wait for her to speak. More than twenty minutes pass and then Hinata finally gathers the courage to say something about the weather, which makes Naruto and Lee burst out ''That was it?!'', making Hinata feel bad and depressed, [[CrowningMomentOfFunny which makes Neji kick Naruto and Lee into space]].
* It's somewhat inverted in ''Manga/OnePiece'' as it's the younger brother, Monkey D. Luffy, that deploys this behavior. He goes on a ''rampage'' once he hears that his older brother, Portgas D. Ace, has been taken captive by the [[TheGovernment World Government]] and is on death row. He not only breaks into the heavily-guarded Impel Down and nearly gets himself killed by trying to go against the BigBad Magellan, but also decides to go further to the Marine HQ when he [[YourPrincessIsInAnotherCastle fails to make it in time to prevent his brother from being transferred to his execution site]]. He also gets furious when he comes face-to-face with the man responsible for his brother's capture. When Luffy is taunted that part of the reason that Ace went up against the man is that he [[AndYourLittleDogToo threatened to kill Luffy and turn him in for his bounty]], Luffy [[UnstoppableRage loses control, attempts to flatten him]], and has to be reminded that saving his brother is more important than avenging his defeat.
** However, it can be played straight with the older brother Ace. When he found out that Luffy was being targeted, [[BigBrotherInstinct he wasn't]] [[http://read.mangashare.com/One-Piece/chapter-440/page014.html pleased at all]].
* MadScientist Komui Lee of ''Manga/DGrayMan'' is very protective of his younger sister, ActionGirl Lenalee. So much so that Link, wanting to go into a room which Allen had locked him out of, threatened him with, "you leave me no choice. I am forced to tell Supervisor Komui that you are in a sealed room with Lenalee Lee," to which Allen quickly apologized and let him in. There is also an anime-only {{filler}} episode where Komui mistakenly thinks that Lenalee is going on a date with one of the Order's scientists and has to be convinced to simply stalk them all over town instead of outright killing the guy. He then repeatedly tries to attack and is comically restrained, until eventually he manages to summon a huge robot to aid him.
** An excellent summation:
-->'''Reever:''' "Section Chief Peck, I would advise you [[MaleGaze not to look at Lenalee that way]]."
-->'''Peck:''' "Why? Does she have a lover?"
-->'''Reever:''' "She has a ''brother''."
* Ryo Mashiba from ''Manga/HajimeNoIppo'' was orphaned when he was in high school, so he had to [[PromotionToParent raise his younger sister Kumi]] on his own. Being a borderline SociopathicHero, he ends up as this towards her, and it's both played for drama ''and'' for hilarity.
* Subverted with Seimei Aoyagi from ''Manga/{{Loveless}}''. To him, it doesn't really matter HOW you treat his younger brother Ritsuka. Seimei believes that [[{{Yandere}} Ritsuka belongs to him and will rid of anyone getting in his way]].
* This trope is revealed to be [[spoiler: Folken Lacour de Fanel]]'s main motivation in ''Anime/TheVisionOfEscaflowne''. [[spoiler: Having failed to pass the Dragon rite (and having been mutilated in the process), Folken joined Dornkirk in hopes that he could create a world where his younger brother Van won't have to fight as king.]]
* Kayo's brother in the ''Manga/VampirePrincessMiyu'' TV series has a BigBrotherInstinct at first and then becomes this, trying to kill Miyu for getting close to his baby sister.
* In the manga of ''Manga/DeathNote'' VillainProtagonist Light Yagami claims in an early MotiveRant that part of the reason he's killing criminals ''en masse'' is to make the world a safer place for his little sister Sayu.
** It might even be somewhat true. [[spoiler: Sayu is, after all, the only person he refused to kill when it would be to his advantage to kill her. Then again, it could be that he just realized Mello would keep kidnapping people until he finally did something about it other than kill their prisoners.]]
* In ''Manga/HellTeacherNube'', the demon Bakki can bounce between LaughablyEvil and evil... but if you hurt his little sister Minki, you. are. DEAD.
* Deconstructed in ''Anime/OvermanKingGainer'': [[BigBad Asuham Boone]] will react violently (and {{disproportionate|Retribution}}ly) towards any slight to his younger sister Karin, even minor or ''imagined'' ones. The whole reason why he wants to capture [[TheLancer Gain]] and thwart the Exodus is that he had convinced himself that Gain had seduced and abandoned her, [[spoiler:while the truth is that Gain and Karin had a one-night stand and Asuham overreacted]]. It gets so bad that [[spoiler:during the last episodes, Asuham goes insane with rage and decides to destroy both Gain and the Exodists by awakening the Overdevil, a world-ending EldritchAbomination]]. He gets better, though... Perhaps [[KarmaHoudini too much]].
* When Last Order is kidnapped in ''LightNovel/ACertainMagicalIndex'', [[spoiler: Accelerator]] reverts back into the person he used to be, except in an effort to save her. Slaughter ensues. The lesson in all this? Don't mess with Last Order if you value your life.
** Misaka has shades of this herself when she discovers what's happening to her sisters/clones and what she's willing to go through to stop the Level 6 Project.
* ''Manga/TanteiGakuenQ'':
** [[spoiler: Kunihiko and Akihiko Ichinose]] become this, trying to protect [[spoiler: their sister Kaoru]] from a SmugSnake aunt who wants to become her tutor and steal the fortune she inherited from their MissingMom alongside a PhonyPsychic accomplice. [[spoiler: They kill the psychic first, and then they murder the aunt when she finds out and tries blackmailing them. Only the psychic was their mom under a disguise, having faked her death to save her business and watch over her kids. Whoops.]]
* Both inverted and played straight in ''Manga/FullmetalAlchemist.'' Edward is multiple times in the series confronted with the question of how far he's willing to go to save Alphonse, but sanity and morality usually win out. However, in an early episode of [[Anime/FullmetalAlchemist the 2003 anime adaptation]], Alphonse comments that if something were to happen to Ed, [[spoiler:Al might well go on a killer rampage just like Scar did.]]
** Scar counted as one in the manga and second anime himself (In the first anime they had a rockier relationship). The realization of his brother's death sent him into an uncontrollable rage, during which time he [[spoiler: killed the Rockbells]]. He later moves on to hunting down and murdering State Alchemists to avenge him.
* Phoenix Ikki of ''Manga/SaintSeiya'' embodies this trope when his little brother Andromeda Shun is involved, to the point that putting Shun in life-threatening danger became the default way to work Ikki into any given storyline.
* In ''Manga/ChronoCrusade'', when Rosette Christopher's little brother is kidnapped by the BigBad, she makes a DealWithTheDevil and spends four years training as a ChurchMilitant. The moment she discovers the location of her brother, she travels from New York to San Francisco, guns blazing, killing any demon that attempts to get in her way, all while being the only BadassNormal in the manga ([[spoiler:the anime eventually gave her holy powers]]). In the manga, it all leads to a battle between her and [[spoiler:Joshua Christopher himself]] who is strong enough to tear apart a massive army of demons with his bare hands. ''And she kicks his ass.''
** There's also Fiore, who considers herself as something of a big sister to Joshua. She seems gentle and demure at first, but when the time comes she doesn't hesitate to [[spoiler:die in an attempt to protect Joshua, even going directly against her master's orders in the manga]].
* ''LightNovel/{{Durarara}}'''s Shizuo Heiwajima tends to act like this in regards to his little brother, Kasuka. While he has reason to be concerned for his brother's safety and privacy (Kasuka's a popular actor, and has been stalked by both rabid fans and the paparazzi in the past), Shizuo takes it a bit too far by immediately becoming suspicious of ''any'' mention of his brother by strangers, innocent or otherwise. Said suspicion [[HairTriggerTemper usually escalates into]] [[SuperStrength tree-throwing]].
* Touya from ''Manga/CardcaptorSakura'' has some shades of this because he promised his mother on her deathbed that he'd protect Sakura.
** ''Some''? He jumped over a fence and tried to beat up a 10 year old boy for bullying Sakura! Admittedly, he probably sensed that the boy was a powerful magician [[spoiler: and knew right away that he would someday take his sister from him]], but he spent the rest of the series disliking and competing with Li. Not to mention the reason why he [[WhyDoYouKeepChangingJobs is always at a different job...]]
* Inverted in ''Manga/RurouniKenshin'' in that Enishi is a Knight Templar ''Little'' Brother. So concerned about his older sister's well-being and so seething with pure hatred toward his brother-in-law for [[spoiler: killing Tomoe's fiance, though unbeknown to Kenshin at the time]] that Enishi collaborated with a league of Shogun assassins in order to kill Kenshin - and this was while he was ''ten'' or ''twelve''. [[spoiler: After witnessing Kenshin killing Tomoe (though by accident)]] Enishi became a little psychopath before getting involved in organized crime in order to one day take {{revenge}} on the man who [[spoiler: killed his sister]].
* Lets not forget Urd from ''Manga/AhMyGoddess!'' Urd makes it clear that she will do anything and use any power she has to in order to protect her sisters, Belldandy and Skuld. Urd has to continually "punish" Aoshima after his latest rape attempt against Belldandy or Skuld (he tried to force himself on her when Skuld grew up after Yggdrasil crashed). Urd stood up to her own mother Hild, the Daimakaicho, telling her to stop tormenting "her little sister" Skuld after Skuld incurred her wrath. Also, Urd actually passed the test to become a First-Class Goddess (the highest level that every goddess tries to attain) but declines because First-Class Goddesses have to use their powers to protect everyone; Urd only wants to use her powers to protect her sisters. Since Belldandy goes absolutely postal if anyone even blinks wrong at Keiichi, it is easy to overlook that Urd is a Templar Knight Big Sister as well.
* Akira's older brothers in ''Manga/AiOreLoveMe'' are quite protective of him.
* More than one SympatheticMurderer in ''Manga/DetectiveConan'' is a brother or a sister seeking revenge for the death or ruin of their younger or older sibling. Some examples are [[spoiler: Toshiya Tadakoro (kills his boss for causing the death of his IllGirl sister while MovingTheGoalposts)]], [[spoiler: Akiko Sayama (kills a corrupt PC programmer for causing her older brother's ruin and suicide)]], [[spoiler: Chieri Aki aka Eri Akechi (kills two {{Alpha Bitch}}es for framing her long-lost younger sister for drug trade and making her commit suicide)]], [[spoiler: Masao Kouda (doesn't kill anyone but becomes a bank robber to hide his loot in the backyard of the man who killed his younger sister and force them dig in to find the girl's corpse)]], [[spoiler: Midori Nozaki (brews a mix of FatalMethodActing and ThanatosGambit to both commit suicide and [[TakingYouWithMe take the woman]] who made her sister kill herself down with her)]] and others.
* [[spoiler: Kanba Takakura]] from ''Anime/MawaruPenguindrum'', as of episode 21. [[spoiler: It ends with his RedemptionEqualsDeath.]]
* Romano from ''Manga/AxisPowersHetalia'' ''tries'', bless him. Luckily for Germany, he can't throw a grenade properly and can't come up with anything worse than [[PlayedForLaughs holding up a stupid mustache so that it looks like Germany's wearing it then breaking down in tears when Germany points out that from his angle, it looks like Romano's the one wearing it]].
** Depending on your interpretation of their relationship, Spain is either this, PapaWolf or [[HoYay something]] [[ShipTease else]] entirely to Romano.
* In ''Manga/HunterXHunter'', Illumi Zoldyck's feelings for his younger brother Killua are...intense. He is extremely protective and possessive of him. Being creepy even by the standards of a family of assassins, his protectiveness manifests in twisted ways. [[spoiler:Such as shoving a needle into Killua's brain to make him into a coward who will flee from any confrontation against a powerful opponent.]] Threatening Killua is also Illumi's BerserkButton. During an otherwise civil conversation, the very moment Hisoka implies he wants to kill Killua, Illumi puts on a NightmareFace and radiates a killing aura so intense that Killua can feel it from miles away. He immediately calms down when he realizes Hisoka was trolling him. It should be noted that Illumi only feels this way towards Killua. He seems indifferent towards Milluki and Kalluto [[spoiler:and he wants to kill/enslave Alluka.]]
* Kagetsu of ''Anime/ShamanicPrincess'' adores his little sister Sara. So much so, that when the PowersThatBe give her as an offering to a powerful sentient magical artifact, he steals the artifact at the risk of causing the collapse of his world to save her.
* Vincent Nightray from ''PandoraHearts'' is one year younger than his brother Gilbert, but his [[{{Yandere}} obsessive]] [[IncestSubtext love]] for him definitely qualifies for the trope. When they were children, [[spoiler: Vincent used his [[ApocalypseMaiden Apocalypse Lad]] powers to destroy ''an entire city'' in order to save his brother.]] In present time, Vincent's stated goal is to [[spoiler: [[SuicideForOthersHappiness erase his own existence so that Gilbert will be happier.]]]]
* During the years of ''Anime/PrettyCure'', many of the Cures who have siblings got angry when a villain dared to attack those said siblings, but the only one who got ''really'' mad was none other than [[Anime/FutariWaPrettyCure Cure Black]], who actually ''killed'' a villain (Gekidrago) for revenge of hurting her AnnoyingYoungerSibling.
* Shinnosuke from ''LightNovel/ApocalypseAlice'', who tries very hard to be TheUnfettered in wanting to save his little sister. To achieve that goal, he's sworn off anything unnecessarily detrimental to him, such as sticking his neck out for others as he can't afford to die before rescuing his sister. That said, keyword is ''tries''.
[[/folder]]

[[folder:Comic Books]]
* [[StrangersInParadise Katina Choovanski]] is quite capable of taking care of herself, but her crimelord sister still keeps interfering in her life - sometimes by [[VillainyDiscretionShot killing people horribly]] because they tried to hurt Katchoo, sometimes by trying to ensure that she ends up with the "right" love interest. Our heroine does not appreciate this.
* [[Comicbook/TeenageMutantNinjaTurtlesMirage Raphael]], while not being the most [[SociopathicHero even-tempered]] character, is psychotically protective of little brother Michelangelo - to the point where he states that the 'thought of Mikey being hurt makes him experience violent rage' (see [[Wiki/{{Wikipedia}} The Other Wiki]]). And considering how violent Raphael is usually...
* Comicbook/SheHulk and the Comicbook/IncredibleHulk are cousins, but they have a Brother/Sister relationship. She-Hulk can take care of herself most of the time, but pity the poor fool who harms She-Hulk within proximity of The Hulk. She-Hulk herself can be extremely overprotective of The Hulk as well. Comicbook/IronMan got his ass handed to him by Ms. Hulk when she found out Stark [[PlanetHulk exiled Hulk into space]].
* How about that time {{Nightwing}} freakin' ''killed'' SelfDemonstrating/TheJoker with his ''bare hands'' when he thought he killed Comicbook/{{Robin}}? Of course, ol' {{Franchise/Bat|man}}s quickly revived him afterwards, but even still.
* {{Quicksilver}} for the ScarletWitch, except that he is her twin, not big brother. But [[RealityWarper recent portraying of Wanda's power]] suggest that if you attack Wanda, you are lucky if Quicksilver kicks your ass before ''she'' has to use her power.
* [[Comicbook/TheMightyThor Thor's]] brother Comicbook/{{Loki}} is a manipulative, deceitful god of lies and mischief, and he often does bad things and sometimes gets punished for themů but if you dare hurt him unjustly Thor will smite you from the face of the Earth.
* In ''[[Comicbook/XMen The Uncanny X-Men]]'', Colossus was this toward his sister Illyana, to the point where he allowed himself to be possessed by the demon Cytorrak and became the new Juggernaut to protect her, losing his humanity and the love of Kitty Pryde in the bargain. Cruelly subverted; Illyana herself had manipulated Colossus into becoming the new Juggernaut to demonstrate that the sweet innocent girl Piotr called "Little Snowflake" was long-gone, replaced by a happily psychotic monster who was not worth saving. When he learned the truth, Colossus vowed that he would kill Illyana if they ever met again.
[[/folder]]

[[folder:Fan Fic]]
* The Kage Tenshi's [[FanficRecs/MartinMystery The Red Monarch's]] Sousuke Miyabe is one for his little sibling [[OriginalCharacter Tatsuki]]. To put things into perspective, 10 years ago, he [[spoiler: kills several Center agents, nearly kills M.O.M and [[OriginalCharacter Colin Price]] and even kills his own parents when they try to protect Colin.]] Tatsuki saw ALL OF THIS, which comes back in literal nightmares. To get the full story, if you read the spoilers, read [[http://www.fanfiction.net/s/3645440/1/The_Red_Monarch/ The Red Monarch]] until you reach the most recent chapter, as it is still ongoing. The link directly to the story is provided for convenience.
* In Murderer's Row, a [[AlternateUniverse Prison AU]] of ''Machinima/RedVsBlue'', Grif and Simmons were thrown in prison for murdering a man who hospitalized Sister.
* In ''Fanfic/MagicaMadokaVeneficusPuella'', Sayaka adopts an orphan. Someone kidnaps her. [[CaptainObvious Do the math.]]
* In ''Fanfic/KitsuneNoKenFistOfTheFox'', Neji is a Knight Templar Older Cousin for Hinata, going to varying lengths to keep Naruto away from her, up to and including attempting to manipulate events so Naruto will get kicked out of Konoha High School. Hiashi approves, especially after they find out Naruto was one of the legendary Nine Terrors, but Hinata herself is not pleased.
[[/folder]]

[[folder:Film]]
* ''Film/TheBlindSide'': Michael is usually a GentleGiant, but [[spoiler: a drug dealer hits Michael's BerserkButton by [[WhereDaWhiteWomenAt making sexual comments]] about Collins, and Michael flies into an UnstoppableRage.]]
* Do not hurt Molly in ''Film/SleepawayCampIIUnhappyCampers'', emotionally or physically. Angela will kill you for it. Just ask Ally, who was DROWNED IN AN OUTHOUSE for committing that crime!
* When the protagonist of ''Film/SickGirl'' finds out her little brother's being bullied, she hunts the three bullies down, kills one of them, and forces the lead bully to drown the other, then ties him up in her barn and spends several days torturing him to death.
* ''Film/DeadMansShoes''. Somewhat after the fact, older brother Richard returns from the army after discovering his brother has been bullied and goes about giving the bullies a taste of their own medicine with interest.
* Haru from ''Film/BeverlyHillsNinja'': "I may not be the Great White Ninja, I may not be one with the universe but I know this...NO ONE MESSES WITH MY BROTHER!"
* The titular character of ''Film/GingerSnaps'' starts out as a Knight Templar Big Sister and gets steadily worse over the course of the movie, as her transformation into a werewolf makes her more and more aggressive. For example, she kills the janitor because she thought she saw him look down Brigitte's top earlier in the movie.
* J.J. Hunsecker in the dark FilmNoir ''Film/SweetSmellOfSuccess'' ruins his little sister's boyfriend's life because he doesn't approve of him for her.
* In the 1938 Yiddish film ''Mamele,'' Khavkhe (Molly Picon) takes care of her whole family. A gangster, Max Katz, recruits her brother into a burglary gang, and courts her sister (with the intention of turning her into a prostitute). Khavkhe manages to pickpocket Katz's gun, and makes him write a letter breaking up with the sister. ("You may be a Katz (cat), but you'll leave here as a kitten.")
* ''Film/FourBrothers'': Bobby Mercer is already pretty [[BloodKnight violent]] [[HairTriggerTemper and short-tempered]] to begin with, but [[BerserkButton hurt his younger brothers]] and he [[IllKillYou WILL]] put you in either the hospital or a body bag. He proves this multiple times throughout the movie, especially when he goes on a [[RoaringRampageofRevenge murderous rampage]] against Detroit crimelord Victor Sweet and his cronies after [[spoiler: the murder of youngest brother, Jack]].
* Tony Montana from ''Film/{{Scarface 1983}}''. He's just a ''tad'' bit overprotective of his little sister Gina, even going as far as [[spoiler:murdering Manny Ribera, his best buddy for sleeping with her right behind his back. Though unbeknownst to him, said friend is already married to Gina the day before]]. Worth noting that more than one critic has observed an [[IncestSubtext incestuous undertone]] to some of Tony's actions [[spoiler:which Gina also accuses him of when she tries to kill him in revenge.]]
* ''Film/AlphaDog''. When Jake Mazursky learns that Johnny Truelove has kidnapped his little brother Zack to get back at Jake, he promises his estranged stepmom that he will do anything to get Zack back. Jake immediately goes on a rampage, crashes a local house party held by some of Truelove's friends by beating up half the people in the room and when Truelove calls him up, Jake threatens Truelove with enacting brutal and painful vengeance unless he releases Zack. Subverted however, as it doesn't help Zack's return at all and prompts Truelove to relocate with his victim.
* ''Film/AmericanHistoryX'': Derek threatens to feed Cameron's heart to him if he continues trying to corrupt Danny like he did with him.
[[/folder]]

[[folder:Literature]]
* ''Literature/CalLeandros'':
** Niko Leandros would burn the world to protect his brother. The only reason Cal ever gets near to any combat is because Nico is a firm believer that the only way to be ready for combat is to actually participate in it.
** Cal reciprocates the sentiment just as strongly. And considering he's slowly slipping into a [[SociopathicHero Sociopathic Type V]] AntiHero over the course of the series with Niko as his sole MoralityChain...the question isn't ''if'' he kills you, but how much he'll make it hurt before he does so.
* [[spoiler: James Vane]] from ''Literature/ThePictureOfDorianGray''. His little sister [[spoiler: Sybill]] killed herself when he was working abroad, so when he found out, he swore to kill the culprit, Dorian Gray. [[spoiler: He ''almost'' got his wish, but was accidentally shot to death.]]
* In ''HellsChildren'', by Andrew Boland, you never, ever, F%*& with Acheri, or her defacto big Brother, Precision, will MindRape you.
* If you decide to [[spoiler: kill and eat]] [[TheSilenceOfTheLambs Hannibal Lecter]]'s baby sister, don't be surprised when her brother tracks you down and makes a shish-kebab of your cheeks. With mushrooms.
* Gretchen Richter in ''Literature/SixteenThirtyTwo'' is a gender-switched version of this, for her brother Hans.
* Max in ''MaximumRide''. She's normally a calm and easy-going person. However, she treats the flock like her own brothers and sisters. If you're foolish enough to [[TemptingFate threaten one of them]], you're gonna regret it.
* Thresh in ''Literature/TheHungerGames'' seemed to take Rue, the girl from his district, in as a sister because when she died, he was infuriated by her death. During the feast, Thresh overheard Clove talking about Rue to Katniss. Thresh grabbed Clove off Katniss, strangled her while holding her one foot off the ground, and yelled at her about Rue. He then kills Clove to avenge Rue.
* You do NOT mess with [[Literature/TheDresdenFiles Thomas Raith's]] siblings, not even if you're their father. Especially his younger sibling[[spoiler:s Inari and Harry (who, though younger, reciprocates the sentiment as Thomas is his only living relative left and shares many similarities with him)]].
[[/folder]]

[[folder:Live Action TV]]
* [[Series/TheXFiles Scully's big brother]] Bill. It's really annoying, since this is a woman who has been shown to be able to handle herself time and time again amongst a predominantly male-oriented workplace. She goes out of her way to never be accused of special treatment because she's a woman. And yet she lets Bill push Mulder around all the time.
** It's not all the time. Bill and Mulder meet about twice in the entire course of the series, and though Bill bad-mouths Mulder, the fights between the men usually happen when she's not around. Not to mention Mulder is capable of holding his own in those fights. The annoyance of this trope comes more from the fact that Bill is making assumptions with half the story.
** Also slightly justified when it comes out that Bill has always acted like this as a result of having to be "the man of the house" when his father was away at sea, and that Dana has always taken his opinion with a grain of salt. It's not only Mulder Bill has a problem with, but her having a life different from what was expected of her: joining the FBI rather than practicing medicine, not getting married, [[spoiler: having a child out of wedlock]]...Mulder is only a part of it, though a substantial part.
** And though his little sister is gone for the entire series, Mulder could most definitely count. He's spent his entire adult life searching for and avenging his sister's kidnapping. Samantha Mulder is the reason Mulder works on the X-Files and why he is so determined to uncover the conspiracy. He does not hesitate to hurt or kill someone in the process of finding her.
* BigBad Kanzaki Shirou from ''Series/KamenRiderRyuki'' very definitely fits this trope.
* ''Series/{{Supernatural}}'' has the Winchester brothers. ''Both'' of them.
** If you think of even putting a ''single'' finger on Sammy, well then you must be fist ''and'' gun proof. Or if you're an angel, [[ShameIfSomethingHappened messing]] with [[AndYourLittleDogToo Sam]] to get Dean's agreement is a [[BerserkButton bad idea]].
** After making Sam watch Dean die over a hundred times in one episode to desensitize Sam to losing Dean (it doesn't work; after Lilith kills Dean, Sam turns to TheDarkSide for vengeance and the power to [[UnwittingPawn save the world]]) the trickster[[spoiler:/Gabriel]] comments that:
--> "Whoever said Dean was the dysfunctional one has never seen you with a sharp object in your hands."
** You probably don't want to mess with Castiel on Dean's watch (or vice-versa) either, although they are more like unofficially adopted siblings
** Lucifer and Michael might have been trying to destroy one another, but Lucifer got pretty vengeful when Castiel molotov'ed Michael.
* ''Series/{{Firefly}}'': Just don't mess with Simon's little sister.
** For that matter just don't mess with River's big brother. [[CurbStompBattle Pity the poor Reavers.]]
* No matter how he tries to negate it, [[Series/{{Chuck}} ''John Casey'']] seems to take that road in regards to Chuck, even though he always claims it's to protect the Intersect. The Casey Doth Protest Too Much, indeed.
** [[SarcasmMode Of course Casey's just protecting the Intersect]]. That's why [[spoiler:he had his super kickass special forces team abort their current mission and reroute to Ellie's wedding where they crashed through the roof and neutralize all the baddies in a BigDamnHeroes moment, just because Chuck was in trouble]]. Which happened in the brief interim when Chuck ''wasn't'' the Intersect.
* It is revealed in one episode of ''Series/MalcolmInTheMiddle'' that Reese is this to Malcolm, and that was the only thing keeping him from getting beat up for his smart mouth. Malcolm finds this out when his brother decides to be nice for the rest of his life.
* Don Eppes of ''Series/{{Numb3rs}}''. How many people were expecting him to kill someone during ''Breaking Point''?
* Justin, from ''Series/WizardsOfWaverlyPlace'', tells his younger sister, Alex, that he always thought he would intimidate her boyfriends if they got out of line and in ''Wizards vs. Werewolves'' he fights Mason (who is in full werewolf mode) for her, ''with his bare hands''.
* Don't get in between [[Series/{{Carnivale}} Iris Crowe's]] little brother and... anything. Just don't.
* ''Series/BurnNotice'': ''Do not'' pick on Nate, Michael Westen's little brother. It is unhealthy. [[spoiler:As those involved with Nate's assassination in season 6 will discover.]]
** In the episode "Comrades", there is a deconstruction. Michael meets a Russian woman, named Katya, whose little sister Elena is kidnapped by the Russian Mafia. Michael has to convince her that being a vengeful big sister might actually not be in the little sister's interest.
* ''Series/PrisonBreak'': Don't mess with Linc or Michael will come up with an elaborate plan to destroy you. Don't mess with Michael or Linc will kick your ass.
* ''Series/BuffyTheVampireSlayer'':
** Buffy warns her friends in the season 5 finale that she will kill anyone who tries to lay a hand on her little sister, [[BarrierMaiden Dawn]], TrueCompanions included, even though Dawn's death [[AlwaysSaveTheGirl might prevent the apocalypse]], and Dawn is [[CosmicRetcon a magical creation]] [[YoungerThanTheyLook only a few months old]] instead of a natural-born sibling.
** In Season 2, Willow is kidnapped by a group of vampires looking to revive [[BigBad The Master]], intending to use her (and a few others) as a human sacrifice. Xander, who blames this on Buffy being depressed and distracted after being clinically dead, threatens to "kill [her] myself" if Willow isn't rescued unharmed.
* Jing Tian from ''Chinese Paladin 3'' boomerangs from having a simple BigBrotherInstinct to full on Knight Templarhood. For example, his reaction on seeing his best friend "threatening" his little sister with a HealingShiv is to attack and nearly kill him.
* Cesare [[Series/TheBorgias Borgia]] is this to a somewhat frightening degree in regards to his younger sister, Lucrezia. By the third episode he's threatening to cut her husband-to-be's heart out with a dinner knife if he's "ungallant". He shows some signs of this towards one of his younger brothers, Gioffre. [[CainandAbel Not so much with Juan.]]
* In {{Series/Arrow}}, Oliver's sister Thea takes a new drug called Vertigo and drives under the influence due to family issues. So Oliver does the reasonable thing and visits her in the hospital, and then he tries to support her legally, especially after the judge wants to make an example of her, and tries to help resolve the family issue that led to the car crash. So why is this entry here? Because he also [[spoiler:tracks down the drug lord that made the drug and sells it, known as The Count, and injects him with the very drug in its purest form in an insanely large quantity, leaving him insane due to the drug making him imagine being in the most excruciating pain possible. The episode ends with him spasming violently and screaming strapped to a hospital stretcher as a doctor explains his extreme condition.]] And he never got NEAR Thea, only being an indirect cause!
* ''{{Series/Friends}}'' - Ross attempts to be this to Monica after she got engaged to Chandler, stating that if Chandler ever hurt her, he was going to "...hunt him down, and KICK HIS ASS!". The rest of the friends (including Chandler himself) found this hysterical.
* On ''Series/{{Youngers}}'', Jodie's brother is this. He threatens to beat Jay up for just looking at her and when Jay breaks up with her, she tells him, which leads to a beatdown.

[[/folder]]

[[folder:Myths and Religion]]
* Absalom from Literature/TheBible, who learns that his sister Tamar was raped and humiliated by their half-brother Amnon and, instead of telling their father David to demand punishment, he goes and kills Amnon himself.
** In all fairness, David was already well aware of what had occurred (see 2 Samuel: 22-23). His response was to be 'very angry'... and do absolutely nothing. Absalom decided to take justice into his own hands - it was obvious none was forthcoming from their father, the king.
* In a similar incident two of the sons of Jacob killed everybody in a village for mistreating their sister. Presumably they wished the feud to [[LeaveNoSurvivors end right away]].
** To put it into perspective, Jacob's daughter Dinah had been raped by a prominent member of the village who fell in love with her. Despite the circumstances, he and his father wanted to smooth over relations with Jacob's family and offered to pay for her dowry as if she'd still been a virgin, [[ValuesDissonance which was actually quite a generous offer at the time]]. Jacob seemed to warm up to the offer, but his sons demanded that all the men of the village circumcise themselves to become part of Jacob's tribe. The men agree, with the idea that they will now be able to intermarry with Jacob's tribe. After all the men are circumcised and helpless, though, Dinah's brothers take advantage of the situation and slaughtered the entire village, taking only women and children alive as slaves. When Jacob [[WhatTheHellHero bemoaned them for the actions]], saying that no one would trust him now, they only reply: [[MyGirlIsNotASlut "Our sister should not be treated like a whore."]] Jacob went along with this right up until just before he died, at which point he called them in and disinherited them for wiping out an entire village for the actions of one man. (Historians believe this story was written in part to explain why those tribes of Judea were on the bottom of the social ladder.)
* In The {{Mabinogion}}, Efnisien gets very angry when his half-sister, Branwen, is married to the king of Ireland:
-->''And thereupon he rushed under the horses and cut off their lips at the teeth, and their ears close to their heads, and their tails close to their backs, and wherever he could clutch their eyelids, he cut them to the very bone, and he disfigured the horses and rendered them useless.'' And this is just his initial reaction.
** And when Branwen's husband starts treating her like a slave, all her brothers go to war to defend her honour.
* Apollo of GreekMythology tricked his sister Artemis into killing her almost-love-interest Orion because he didn't want her to break her vows of chastity.
[[/folder]]

[[folder:Toys]]
* The filecards for Franchise/GIJoe members Barrel Roll and Bombstrike, and the filecard for Cobra operative Blackout contain a story where Barrel Roll acts as Knight Templar to rescue his sister Bombstrike after blacksheep brother Blackout kidnaps her.
[[/folder]]

[[folder:Video Games]]
* Gulcasa of ''VideoGame/YggdraUnion''. Serious harm befalling his younger half-sister Emilia induces BerserkButton-level rage, and towards the end of the game--directly after he learns [[spoiler:that she has been killed by the Royal Army]]--said rage causes him to reject Yggdra's repeated pleas for a cease-fire to the war that has [[spoiler:''effectively destroyed most of his country'']]. Usually, he's a shrewd and reasonable ruler, but in this case...
** Emilia actually inverts the trope in one of the routes of ''VideoGame/BlazeUnion'' where Gulcasa never discovers his powers (or that they're related), and purposely risks going permanently AxCrazy in order to get the power to protect him and the rest of her adoptive older siblings in Gram Blaze. On the chance that she actually does go insane, [[spoiler:Gulcasa is left StakingTheLovedOne, after which he [[HeroicBSOD crawls into his]] [[Anime/NeonGenesisEvangelion Shinji corner]] [[DespairEventHorizon and doesn't come out]].]].
* Don't get anywhere near ''VideoGame/TheLegendOfZeldaTheWindWaker'' 's Aryll, or prepared to be mercilessly hacked into pieces by the Master Sword. Good thing Link's an only child in all of the other games.
* [[HandsomeLech Zelos Wilder]] in ''VideoGame/TalesOfSymphonia''. Though Seles seems to hate him for being born [[spoiler:since her mother tried to kill him so that Seles could be TheChosenOne instead, but Zelos' mother [[TakingTheBullet saved him]], and as a result Seles' own mother was executed]], he will "throw anyone who so much as looks at her wrong down the Palmacosta harbor". Whoa, dude, chill.
** [[spoiler: [[BigBad Mithos Yggdrasil]] from the same game. [[EvilPlan He split the world into two and caused everything that leads up to the main plot.]] His goal? To resurrect his sister.]]
** Guy Cecil from ''VideoGame/TalesOfTheAbyss'' -- his older sister Mary [[spoiler: may be dead]], but he practically raised Luke. Guy's a pretty chill person normally, but if you so much as threaten one hair on Luke's head, you press his BerserkButton. Especially evident during the Summit, when [[spoiler: Jade suggests Luke die in Asch's place, and Guy ''grabs Jade by his collar'', actually ''yells'', and calls Jade a bastard for it.]]
* In ''VideoGame/TalesOfXillia2'', this ends up being inverted [[spoiler: if you choose to see the bad ending by making Ludger refuse to kill his older brother Julius (Something the latter wants, as he's doomed, and it's the only way to extract a Soul Bridge from him, a key that the party needs to save the world). Gaius proceeds to state that he'll do the deed himself, then things get ugly from there. ''[[KillEmAll Really ugly.]]'']]
* [[spoiler: Beat]] from ''VideoGame/TheWorldEndsWithYou'' makes a FaceHeelTurn in reaction to [[spoiler: Rhyme dying; he becomes a Reaper in the hopes of restoring her to life.]]
* Targeting [[VideoGame/Disgaea2CursedMemories Axel's]] little brother is not a good idea, something a repo man learned the hard way at the end of the Axel story. And as aforementioned Dark Hero learned the hard way, do not abduct Adell's siblings or Rozalin's "servants". ''For any reason at all''.
** The plot of ''VideoGame/DisgaeaDimension2'' can be summed up as this given that [[spoiler: Xenolith would allow the Netherworld to transform into something similar to Celestia as well as give up his life if it means saving his little sister Etna. Alas Etna constantly refuses to acknowledge that Xenolith is her older brother even with her life on the line. Of course one particular bad ending has Xenolith fail to save Etna when she refuses to acknowledge that Xenolith is her older brother and destroys the artifact that is destroying the Netherworld with her powers in it. That power ends up killing her and everything he has done had been for nothing.]]
* And let us not forget that ''VideoGame/MegaMan'' and Proto Man are basically teaming up together in ''10'' to get the vaccines for Roboenza, to cure Roll. Hell Mega Man goes after Wily before he goes after the Robot Masters. Whoever created this virus better have good life insurance. [[spoiler:Yeah, Wily's life insurance is up to date. [[JokerImmunity Bastard]]'s ''[[JokerImmunity still]]'' [[JokerImmunity alive]].]]
** Blues in ''Manga/MegaManMegamix'' fits the 'morally questionable actions' part of the trope (what separates it from BigBrotherInstinct), up to and including ''threatening to kill Kalinka Cossack'' if anyone gets involved in [[spoiler:the MirrorMatch between Mega Man and Copy-Mega Man]]. Of course, [[spoiler:not only was there the risk that they'd shoot the wrong one if they'd tried to help, but Dr. Wily had given Shadowman orders to take advantage of the chaos to kidnap Kalinka. Blues couldn't help Mega Man fight without letting Kalinka get snatched, and he needed some way to keep the other robot masters present from trying to help Rock and causing the FogOfWar Wily was going for. If he hadn't threatened her, they would have tried to go through him, and Shadowman would have taken her while he was distracted. By the side of the one with the ''shield'' was the safest place for a human among a lot of robot masters with itchy trigger fingers, and]] he did succeed in saving everyone [[spoiler:except Copy-Mega Man.]] There are plenty of other examples.
** Consider that Wily based his own robot designs on Proto Man's specs. Bass would then be multiple inversions of the trope: he's on a constant mission to destroy Mega Man, and if Wily pisses him off he'll gladly take it out on the other Wily bots...who are also Proto Man ripoffs.
** Any attempt to harm VideoGame/MegaManX or Zero in the other's presence will result in the survivor of the pair ''bringing the BigBad's fortress down on top of you.'' In later games, if you take out Axl, you now have to deal with TWO pissed-off Knight Templar Big Brothers.
* ''VideoGame/{{Prototype}}'': Whatever happens, whoever you are, whatever the reason, never ''never'' '''never''' harm Dana Mercer in any way, because the consequences for doing so come in the form of her big brother, Alex. Alex is a shapeshifting, superstrong, superfast, superagile, incredibly resilient HumanoidAbomination with ''[[UnstoppableRage issues]]'', and Dana is the [[MoralityPet one thing in the world he cares about]]. Alex once prevented Dana's capture by punching ''through'' the torso of a soldier wearing body armour. Alex [[ImAHumanitarian ate]] a few dozen people who [[BrainFood happened to be vaguely connected]] to Dana's location when kidnapped, and two monsters, and the mastermind herself. [[MindHive Alex is already]] [[LovecraftianSuperpower not wholly stable]]. Try something safer, like playing Chicken with the sun. [[spoiler:And in a wholly depressing twist, Alex isn't even really Dana's brother, simply a virus wearing her brother's corpse like a suit. The real man cared so little about his younger sister that he ''knowingly'' condemned her to a hideous death with the rest of the world when he released the virus, before he died and it consumed his remains. This was a man so devoid of love that a flesh-eating virus designed specifically to wipe out humanity cares for his sister more than he did. [[MoralEventHorizon What a dick.]]]]
** In the [[Videogame/{{Prototype2}} sequel]], [[spoiler: Alex appears to have dropped this trait, [[RogueProtagonist alongside almost any positive traits he had]]. Though it should be noted that despite Dana working against his evil plan, he chooses to capture her, rather than just kill her like he did Heller's other contact, Father Guerra.]]
* In ''VideoGame/{{Persona 4}}'', acting this way and [[spoiler:throwing Namatame into the TV after Nanako's apparent death]] will get you [[NiceJobBreakingItHero the worst ending]].
** PlayedForLaughs in ''VideoGame/Persona4Arena'', where Yu is given the EmbarrassingNickname "The Sister Complex Kingpin of Steel".
* Axel of ''Franchise/KingdomHearts'', towards Roxas. He raises the amnesiac keyblade-wielding Nobody... but he's also a ''really'' PoisonousFriend.
* In ''VideoGame/GrandTheftAutoSanAndreas'', [=CJ=] finds out that some construction workers have been calling his sister Kendl a hooker. Not only does he bust up the portables at the construction site, but he also traps the foreman in a porta-potty and [[DisproportionateRetribution uses a cement mixer to]] ''[[BuriedAlive bury him alive]]''. And all the while, the poor guy is screaming [[CrossesTheLineTwice "OH GOD, WHY?!"]]
* ''VideoGame/DirgeOfCerberus'' messes with this. It's actually the little brother, Nero, who goes completely batshit when his big brother is threatened.
* [[spoiler:Albus]] in ''VideoGame/CastlevaniaOrderOfEcclesia''. [[spoiler:Pretty much does everything he can to protect Shanoa in the first half of the game, going so far as to appear a villain for it, until Barlowe is outed, anyway.]]
* The protagonist of the [[NoExportForYou Japan-only]] ''VideoGame/NieR Replicant'' is TheUnfettered when it comes to protecting his sister Yonah (in the Western version, he's instead a PapaWolf).
* In ''VideoGame/DragonAgeII'', the player character can act like this towards a younger sibling, Bethany or Carver. And considering what can potentially happen to them throughout the game, it's no wonder.
** It's much more prominent with Bethany however, such as when Ser Wesley identifies Bethany as being an Apostate, causing Hawke to [[EstablishingCharacterMoment immediately]] step [[BigBrotherInstinct in front of her]] and stare down the Templar with a DeathGlare. This even happens if Hawke is a Mage, putting themselves potentially in the line of fire to protect her. [[spoiler: Should Bethany go to the Circle, Hawke similarly threatens to disembowel any Templar who touches her, only relenting when Bethany explains she's going peacefully and by her own accord]].
* A possible sidequest in ''VideoGame/TheGodfather 2'' involves you being told to beat up or kill someone taking advantage of the quest-giver's sibling.
* In ''VideoGame/{{Borderlands 2}}'', it's implied that Scooter acts like the trope towards his sister, Ellie, despite Ellie telling Scooter to leave her alone and stop setting her customers on fire.
[[/folder]]

[[folder:Visual Novels]]
* ''Franchise/AceAttorney'':
** Phoenix Wright is like this with Maya Fey, his assistant. Since this can sometimes be thought to be a ShipTease by some fans, it is noticeable that he would run across a ''burning bridge'' to save her from a cave, and break down a door that led to her after hearing a gunshot in the room. And Maya is also this way towards her cousin, Pearl, as she was enraged when Phoenix suspected her of any wrongdoings in the second game.
** Another example is the Blackquills from ''Dual Destinies''. Simon is this towards Athena, as he went through death row for her sake and was willing to threaten Phoenix in court if he tried to prove her involvement in a case. Same with his older sister Aura, who held an entire building of people hostage to allow her brother to be acquitted from false murder charges. Guess this runs in the family.
* Clover in ''VisualNovel/NineHoursNinePersonsNineDoors'' has a suspicion on who killed her older brother, Snake, in Door 3. In the Axe Ending, when she calculates who the murderers are, she acts on said misconception, [[spoiler:killing both Santa and Seven, the suspected murderers, and June, the protagonist's lover for defending them, before turning against the protagonist himself]]. Though depending on how well the game is played, the players can get the True Ending, where Junpei befriends her and inadvertently stumbles across a crucial clue that indicates [[spoiler:her brother is still alive.]]
* [[spoiler: Kaoru "Sou-Banchou" Ichimonji]] from ''Franchise/TokimekiMemorial 2'' is revealed to be this if you romance his younger sister, [[spoiler: Akane]]. And this is [[spoiler: ''the main character's own fault'': Sou-Banchou witnessed first-hand [[LoveHurts how utterly heartbroken]] [[HeroicBSOD the poor girl was]] was when you-as-the-MC moved outta the city, so he swore to pretty much punch the HELL outta any guy who made her cry.]]
[[/folder]]

[[folder:Web Comics]]
* Johan of ''Webcomic/AndersLovesMaria'' has long been violently protective of his little sister, Maria. Leads to him committing acts of vandalism and assault in her name.
* Mijuu of ''Webcomic/{{Juathuur}}'' is Dejoru's overprotective big sister.
* ''Webcomic/{{Panthera}}'' has Jason, who threatens his best friend Fletcher (who finally got a date with Taylor) as such:
--> '''Jason:''' If you do '''''ANYTHING''''' to her, in '''any way, shape or form''', I will quite literally '''#%$&!$# EAT YOU'''. And you have '''NO''' idea just how '''DEEP''' I could '''BURY''' what'd be left of your sorry '''carcass'''. '''UNDERSTOOD?'''
[[/folder]]

[[folder:Web Original]]
* ''WebAnimation/BrokenSaints'': Tui Jr, adoptive brother to HeartwarmingOrphan Shandala, can resemble this at times, due to his being so hot-blooded.
* Lenny Priestly of ''Roleplay/SurvivalOfTheFittest'' v3 will do ''anything'' to make sure his twin sister Elizabeth is safe. Literally anything, as he kills people for this reason. Though possibly a subversion, as it has been implied that he used her as an excuse to kill, especially since he went AxCrazy and stopped being an AntiVillain.
* In ''Literature/{{Brennus}}'', Amy is very ''very'' protective of her younger brother Basil, although she doesn't tell him about everything she does. He still thinks [[spoiler: some of the Hemogoblins]] got away. She tore them limb from limb.
[[/folder]]

[[folder:Western Animation]]
* Dee Dee from ''WesternAnimation/DextersLaboratory'' may appear to be a flake, but you do NOT harm her little brother. Or she will kick your ass.
* While they're on separate sides, Protoman from ''WesternAnimation/MegaMan'' certainly fits. No one, save Protoman himself, is allowed to touch Mega Man -- not even Wily. True, he [[TheOnlyOneAllowedToDefeatYou states that wants to defeat Mega Man himself]], but [[WeCanRuleTogether not really]].
* Kenny [=McCormick=] from ''WesternAnimation/SouthPark'' displays this in the episode "The Poor Kid". If you have the gall to mess with Karen [=McCormick=], Kenny proves that he WouldHitAGirl quite viciously, as Jessica Pinkerton finds out. The rest of the school gets the hint that the girl is off limits.
[[/folder]]
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