* ''Fanfic/{{Downfall}}'' is chock full of (relatively) nice, non-combative people. When they decide to get busy it tends to get ugly, mostly because the non-aggressive characters are usually the more powerful ones.
* Fanfic/TheWizardInTheShadows has Harry, after he opens up a little. Nice, friendly, caring and slightly but harmlessly mad. Until you hurt someone he cares about. Then you are reminded that he ''earned'' his status as TheDreaded for the forces of evil, and that he is the most powerful mortal wizard alive. When Harry gets angry, craters the size of soccer pitches are left behind and the Nazgul make for the hills.
** Emrys. Cheerful {{OC}}, TagalongKid and ServileSnarker. Then he [[LetsGetDangerous gets dangerous]] when he finds out what happened to his sister. This is before he becomes a truly terrifying badass.
* ''FanFic/{{Stray}}'' contains an incident where this trope is applied to Otacon, of all people. It turns out that the quirky, tenderhearted, [[NonActionGuy non-action]] anime geek can be dangerously resourceful when backed into a corner.
* In the ''WesternAnimation/ChipNDaleRescueRangers'' fan comic ''Fanfic/OfMiceAndMayhem'' [[spoiler: Gadget, usually the epitome of kindness, attacks the men who were after her when Chip gets shot trying to protect her]].
* Latias from ''[[http://www.fanfiction.net/s/2053520/5/Latias_Journey Latias' Journey]]''. She's depicted mostly as a gentle, somewhat timid and fearful Pokemon. That changes ''big time'' in Chapter 5. [[spoiler:After watching a bunch of evil bird Pokemon butcher a bunch of baby Flying and Bug types in Wing Fortress, she goes completely apeshit. The end result: a bunch of enemy Flying types lying in pieces in nursery, followed by a Psychic attack so powerful that it could best be described as a [[FantasticNuke psychic nuke]]. ''That'' is followed up with an even more ''obscenely'' powerful Fire (or Dragon) attack that completely ''obliterates'' Wing Fortress and a large piece of the surrounding forest.]] It is ''utterly terrifying'' but at the same time ''[[PrecisionFStrike fucking]]'' [[CrowningMomentOfAwesome awesome]].
** [[spoiler: [[NiceJobBreakingItHero And killing the rest of the Pokemon she was trying to save.]]]]
* In the ''Yu-Gi-Oh! GX Spirit Caller'' fan fiction, the protagonist Kaigen Kou is usually calm and slow to anger, but bullying or mistreating his friends releases a terribly ruthless and somewhat psychotic side. It's a bad idea to bully his friends, but sully the reputation of the woman he loves and you'll find yourself beaten half to death and inches away from being LIT ON FIRE.
* [[http://www.fanfiction.net/s/3547876/1/When_Summoning_Please_Watch_The_Wording This]] {{Crossover}} fic between ''Literature/GoodOmens'' and ''Series/{{Supernatural}}''. [[OurAngelsAreDifferent Aziraphale]] unleashes some truly [[CrowningMomentOfAwesome righteous fury]] on some wannabe Satanists who have crossed the MoralEventHorizon to summon the wrong yellow-eyed demon.
-->''Aziraphale's expression was like thunder. "Come to me, my child," he said, his tone as cutting as diamonds. "And I will [[GoMadFromTheRevelation show you a true wonder of a miracle!]]"''
* In ''Fill the Moon'', when Demyx happens to witness [[spoiler:Xigbar being slightly wounded by Captain Barbossa,]] that minor injury towards his [[HoYay lover]] is enough to get him to snap, summoning a hurricane and capsizing the Black Pearl, along with drowning around one hundred Heartless and keeping the entire pirate crew at bay with the power of his magic. Don't piss off Demmy-kins.
** Another nice, cute, sweet [[MessianicArchetype messiah]] you don't piss off? The little girl called Senayax. Once you lay a finger on her family or her pet Heartless, you are in for an absolute world of hurt. [[spoiler:Hollowmoon, the {{Eldritch Abomination}} that lives inside her, and Kingdom Hearts itself? They found that fact out the hard way.]]
* Granted, Eija Satomi from FanFic/DivineBlood isn't adverse to dealing lethal force when necessary, but she is still extremely friendly, patient, kind and generally feels remorse when she is forced to kill. However, after the ghost of her [[HomosexualReproduction second]], [[HalfHumanHybrid divine]] [[ChildByRape mother]] killed the first blood-related adult other than her own mother, apparently out of no reason than spite, Eija's response was violent enough to catch the attention of an ongoing psychic battle between the [[TheVirus soul(s)]] of a HumanoidAbomination and several Gods and Demons. The HumanoidAbomination ran away while almost everybody else watched Eija seal the ghost by drowning it in psychic representations of blood.
** Later,Kasumi ''kills a banquet hall full of rebel gods'' using what appears to be ''blood magic-based poison'', given that it was triggered by ''stabbing her own hand'', which caused them to sudddenly keel over one by one.
* Uriel in ''Fanfic/ManchesterLost''. One moment he is falling off the edge of heaven (which Raphael notes has no edges) and forgetting how to fly, as well as being a general CloudCuckoolander the next [[spoiler: he is throwing the 3rd most powerful demon in hell through several buildings and the remains are sizzling and in bits. Then, after a long battle, he nearly succeeds in ripping Lucifer in half, and throws him all over the place.]]
** Aziraphale in the same fic. After he [[spoiler: briefly falls]], he gets so angry, that even Beelzebub Lucifer's second is frightened of him. Unfortunately he is distracted. [[spoiler: Later however, he [[IncendiaryExponent sets himself on fire with holy flames]], leading to CrowningMomentOfAwesome when he dispatches Beelzebub in a TakingYouWithMe moment.]]
** In fact, this trope is such an essential part of this fic that [[http://www.fanfiction.net/s/4818516/11/Manchester-Lost one of the two rules of Hell]] is "LEAVE THE NICE ONES ALONE."
* The dwarven noble protagonist in DragonAgeTheCrownOfThorns expected Faren, the DC, to hate him when he revealed to him that [[spoiler:he always knew Rica was Bhelen's concubine and had never said anything.]] Faren doesn't ''really'' end up hating him but, since he hates Bhelen's guts (among other, deeper reasons), he still [[spoiler:delivers a NoHoldsBarredBeatdown to the prince, leaving him with a broken jaw and a couple of snapped ribs for good measure, plus a swollen eye.]] At least Faren ends up regretting it, after getting a WhatTheHellHero speech from Kallian Tabirs, the city elf warden and [[spoiler:his love interest,]] plus finding out just why the guy withheld that from him. He only really realizes just how badly he flipped out after remembering that [[spoiler:the DN has a particular problem that prevents healing magic from working on him, so Wynne can't just snap her fingers and make the horrid pain go away.]]
* [[http://www.fimfiction.net/story/90939/1/shell-shock/the-tower In Shell Shock]], this is combined with SadisticChoice and BreakTheCutie in an extremely poignant way at the climax. "One more- give him one more! *BOOM!*" Given who [[http://www.fimfiction.net/user/kalash93 the author is,]] it's not all that surprising.
* This trope shows up in three other stories also by [[http://www.fimfiction.net/user/kalash93 Kalash93.]]
** In ''FanFic/RacerAndTheGeek'', the protagonist is a very nice guy. He's also employed as a mercenary and [[http://www.fimfiction.net/story/81159/1/racer-and-the-geek/predawn won't hesitate to pull the trigger]] when it's called for.
** In [[http://www.fimfiction.net/story/85411/1/reflections/solace Reflections,]] Luna cares deeply for Celestia. She also won't let her sister run from her problems.
** In [[http://www.fimfiction.net/story/88520/1/welcome-to-the-brothel/das-laufhaus Welcome To The Brothel,]] the protagonist takes time to write letters to his mother that showcase just how truly vulnerable and sensitive he really is. That doesn't stop him from being a highly effective warrior.
* Roleplay/{{DC Nation}} - Dr. Light had unleashed a toxin that was killing all prepubescent children in North America as revenge for his MindRape at the hands of the JLA, just to make sure that the heroes' children suffered. He captured Sue Dibny to "finish what he started." A JLA strike team was sent after him. Light had them all on the ropes and was dangerously close to killing the Elongated Man when [[http://community.livejournal.com/jla_watchtower/1035178.html?thread=29418666# Sue broke out of her holding cell]], and [[CrowningMomentOfAwesome armed with Hal Jordan's ring, proceeded to open up a literal can of whoop-ass]] on him while cussing him out in English and Yiddish.
** Nationverse actually loves this Trope. Hypertime elemental (and CloudCuckooLander) Shift is normally pretty laid back. When Shift's zombie grandfather almost killed him (during Shift and Miss Martian's first date date), Miss Martian morphed into her giant, scary white martian form and tore the zombie to little pieces. When the zombie grandpa got better moments later, Shift snapped and stranded him in a dead alternate Hypertime after beating him up at superspeed. He thought to himself (in his normal fragmented manner), after the blur of his own movements, "Tastes terrible. Zombies taste like old Slim Jims. Makes sense. Need mouthwash after this." ''The nice one bit off a chunk of his undead grandfather.''
** Another example is Fauna's "freak out" stage. Fauna is a sweet natured, TechnicalPacifist GranolaGirl with abilities (she'll never call them ''powers'') close to Beast Boy's. Push her to the point where her shapeshifting snaps her brain, and she will come at you with everything, including ''cobra venom.''
* In ''Fanfic/DumbledoresArmyAndTheYearOfDarkness'', Dennis Creevey is one of the sweetest, nicest boys you could ask for... until the Death Eaters finally push him too far. "[[CrowningMomentOfAwesome AVADA KEDAVRA YOU SON OF A BITCH!]]"
* In ''FanFic/TheManWithNoName'', the villain utterly fails to do this in regards to [[Series/DoctorWho the Doctor]].
-->'''The Doctor:''' Do that and you will end your days screaming in the deep places of my mind.
-->'''Big Bad:''' Y-you wouldn't do that! You can't!
-->'''The Doctor:''' Why not? You would.
-->'''Big Bad:''' B-but you're the Doctor!
-->'''The Doctor:''' Ah, yes, that argument. Heard that one before. And you know me so well, do you? You called me a monster not long ago. But now–ah, now you plead for the Doctor, the compassionate, merciful, pacifist Doctor.
* ''Fanfic/RiseOfTheGaleforces'' gives us Sarah Squall, who at first glance looks and acts like a fun person to be around. But as various foes can attest to, she is in fact a CuteBruiser who can toss friggin' ''[[EverythingsBetterWithDinosaurs dinosaurs]]'' around like ragdolls. [[IBelieveICanFly And fly.]] Well, she '''IS''' [[TheIncredibles Stratogale]] after all...
** It's probably not a good idea to mess with the rest of her family, either. Sarah's dad [[MakingASplash can drown you with a cupful of water]] and [[TheBeastmaster sic sea creatures on you]], while her mom is a GravityMaster who can suck you into a black hole in [[Memes/MyLittlePonyFriendshipIsMagic ten seconds flat.]] Her uncle is [[DumbMuscle a true dunderhead]], but he can still kick your ass with [[ElementalPowers either]] [[ShockAndAwe lightning,]] [[BlowYouAway wind,]] [[MakingASplash water,]] [[AnIcePerson or ice,]] whatever comes to mind first. Oh, and [[AuthorAvatar Terror]][[OppositeSexClone dactyl]]? Suffice it to say that his name pretty much [[IncrediblyLamePun speaks]] [[OneWingedAngel for]] [[PrehistoricMonster it]][[GiantFlyer self.]]
** The BewareTheNiceOnes/WesternAnimation section provides more details on the OTHER SuperFamilyTeam, but special mention goes to Violet in this case, who [[CharacterDevelopment develops]] into a GenreSavvy CombatPragmatist. [[spoiler:Special note goes to her [[ScaledUp literal]] RoaringRampageOfRevenge in Episode 4, which ends when, after single-handedly [[CurbStompBattle wiping the floor]] with the last of the BigBad's armada, she gets a [[YankTheDogsChain yanked chain]] and a TorsoWithAView thanks to his final bullet... and her temper goes completely off the rails, causing her to order him slaughtered, horribly and ''[[FamilyUnfriendlyDeath on-screen]]'', in front of the entire cast.]] Shy as she is, this is the kind of girl who won't take an insult lying down, and isn't at all afraid to ''[[ShootTheDog kill]]'' if she has to.

* The ''{{Series/Heroes}}'' DarkFic ''[[{{Fanfic/Unmade}} Unmade]]'' gives us this in an instance of intense PsychologicalHorror when {{Emo}} NiceGuy Peter Petrelli ([[BullyingADragon who also just happens to be a]] PersonOfMassDestruction) [[spoiler: goes on a RoaringRampageOfRevenge through Primatech [[BeingTorturedMakesYouEvil after being tortured]] [[DespairEventHorizon to the breaking point]] [[StockholmSyndrome stopping only to free his new BFF]] [[SerialKiller Sylar.]] They LeaveNoSurvivors.]]
* In any [[BlinkyBill Adventures Of Blinky Bill]] fanfics written by Canzet Yote, it is NOT a good idea to piss off [[ShrinkingViolet Shifty]] [[PreciousPuppy Dingo]] or [[TheHeart Nutsy.]]
* [[Fanfic/KyonBigDamnHero Kyon]] doesn't go looking for trouble. He really doesn't. But then someone goes after his TrueCompanions, and he alternately beats them to a bloody pulp or dangles them out a window. And now he has [[spoiler:[[BeamSpam the ability]] [[KillSat to wipe out]] [[MorphWeapon most of a town]] [[WaveMotionGun in one shot]]]].
* [[Darthwiki/NewDawn Matthew Streika.]] Definitely one of the nicest, most decent people in a book full of things trying their very hardest to kill almost everything else, and is trying his best to make sure said dangerous things stay well away from his home town. All he really wants is to make sure innocents don't get involved, and protect his friends. He does not go looking for trouble. That said, do not mess with Matthew. Because when you manage to get him into a fighting situation, he is utterly ruthless and ferocious in a fight, not even minding his own pain until all hostile forces are either running with their tails between their legs or dead.
* Uzumaki Naruto in Fanfic/WhiteRain is usually a happy, friendly, and goofy Hokage. [[spoiler: When he stops being happy, friendly, and goofy, property values in Kusagakure drop in a hurry.]]

* Takato from the ''FanFic/TamersForeverSeries''. A sweet, friendly boy who will absolutely '''''DESTROY''''' you if you push his BerserkButton and this is NotHyperbole, he will ''annihilate'' you.
** It's also considered to be a bad idea to piss off [[TheCutie Jeri]]
* Nia in ''FanFic/TengenToppaGurrenSolvernia'', in her first fight, she tries hard to talk the ganman who is striking the village to stop, seeing no sense in the destruction, but when he threathens to kill everyone in the village, [[BerserkButton Nia snaps]] and [[CurbStompBattle reduce him to scraps]].
* There's been no true hints to it in the story itself as of it, but WordOfGod is that out of the main four in [[http://www.fanfiction.net/s/7986051/1/The_Seven_Names_of_Envy_Angevin The Seven Names of Envy Angevin]] ([[BrokenBird Envy]], [[TheNapoleon Ed]], [[GenkiGirl Ling]], [[OnlySaneMan Russell]]), Russell is actually the most dangerous, despite his general laziness, apathy and sarcasm.
* [[SmilePrettyCure Yayoi Kise]] in ''FanFic/{{Respect}}''. What happens when a weak, timid crybaby gets the power to fight back against TheBully with a [[Anime/PuellaMagiMadokaMagica Puella Magi's]] power? [[spoiler:Answer: An accidental murder, a StartOfDarkness, SanitySlippage, and eventually laying waste to a town.]]
* ''Fanfic/HarryPotterAndTheMethodsOfRationality'' has an ''army''. They're named The Sunshine Regiment, their badge is a smiley face, they make no secret that they're fighting for Good in the most [[TastesLikeDiabetes sickeningly sweet way possible]]... and when the battle commences, they win. Their opponents are a child prodigy and a boy trained from birth as a death instrument.
* Driad in ''FanFic/ClashOfTheElements''. [[spoiler: The outer guardian of the Frozen Palace learned this the hard way when Driad regained his memories of his life as an outer guardian and briefly returned to that form to combat him.]]
* Dr. Watson in ''[[Fanfic/DeliverUsFromEvilSeries Mortality]]'' (along with every other relevant Sherlockian work by the author). Ordinarily, he's the nicest guy you'll ever meet. [[BerserkButton But you mess with]] ''Literature/SherlockHolmes'', and may the Lord have mercy on your soul, because John H. Watson will ''not''. In one chapter, he's captured a criminal to interrogate, and he plays the DeadlyDoctor trope disturbingly straight and delivers a pretty scary BadassBoast:
-->“If your master’s actions destroy him whom I regard as — as the ''best'' and ''wisest'' man I have ''ever'' known… make no mistake that I shall hunt down, to a man, ''everyone'' who played a part in his destruction.”
* [=MLP:FiM=] fanfics tend to be full of those.
** In MyLittleDenarians Rarity is a proper lady and sickened at the idea of violence. But when her friends are in mortal danger, she is the first of the group to start using human-made firearms. There is also Twilight Sparkle, who doesn't want to kill anyone but at her power remains extremely dangerous (At one point, when one of her friends is injured, she flips out [[spoiler:with a banishment spell, sending several dozen cultists to the Moon... unaware that Earth's moon has no atmosphere)]]. Last but not least Cheerlee, who goes MamaBear on an enemy stupid enough to take one of her students hostage.
** The adult fic ''Fanfic/{{Xenophilia}}'' gives us Lyra Heartstrings. She is calm, friendly and reasonable, with a lot of sense of humor and a bit of snark. She is also a grand master of the Still Way, a unicorn telekinesis-based martial art, with enough control to NeckSnap you from across the street, without moving a muscle.
** This is how Princess Luna is depicted in ''{{Fanfic/Progress}}''. She is a kind-hearted alicorn, if socially awkward, but not many of the characters who get on her bad side remember the [[PhysicalGoddess alicorn]] part until it's too late. [[BerserkButton Especially if her glasses are broken,]] as Angel has learnt.
** Applies to pretty much every pony in ''Fanfic/AceCombatEquestriaChronicles'', but especially Fluttershy.
** ''FanFic/TheImmortalGame'': Twilight Sparkle, having been trapped inside her mind and [[AndIMustScream forced to watch]] as her SuperpoweredEvilSide, Nihilus, tried to kill her friends, all while mocking her about it, finally manages to [[FightingFromTheInside retake control]] during a critical moment of the ClimaxBoss fight between Nihilus and her friends. Nihilus [[VillainsWantMercy begs Twilight for mercy]], but Twilight coldly refuses and mocks Nihilus, even as the Elements of Harmony are used to destroy her.
*** Which is nothing compared to what Twilight does to [[TheDragon General Esteem]], the stallion who infected her with the ArtifactOfDoom that created Nihilus in the first place. After giving him a TheReasonYouSuckSpeech and forcing his mouth shut to prevent any [[VillainsWantMercy pleas for mercy]], she proceeds to kill him in a ''[[PayEvilUntoEvil brutally]]'' painful manner.
** An example that is actually not from a pony in ''[[FanFic/SonicGenerationsFriendshipIsTimeless Sonic Generations: Friendship is Timeless]]'': Do not make [[VideoGame/SonicGenerations Amy]] angry. Spike found that out the hard way.
-->'''Spike''': WHY WOULD YOU LEAVE ME WITH SOMEONE LIKE HER?\\
'''Sonic''': WHY DO YOU THINK I SAID DON'T MAKE HER ANGRY? WHAT, YOU THINK I WAS BEING CUTE?
** The [[AbridgedSeries portrayal]] of [[WesternAnimation/MyLittlePonyFriendshipIsMagic Fluttershy]] as seen so far in FriendshipIsWitchcraft.
** Fluttershy in the ''Fanfic/PonyPOVSeries'', as can be expected. [[spoiler:Taken to logical conclusion when she ''snaps'' completely, getting corrupted in the same way as Princess Luna was and turning into the second BigBad, Princess Gaia/Nightmare Whisper.]]
*** Later (or earlier, as it may be), during the ''Gaiden: Seven Dreams/Nightmares'' side story, Patch TookALevelInBadass, but still remains the goodhearted clown she's always been. However, her search for the fragments of the Rainbow Of Light leads her to the Pegasus Despot using the Blue Shard of Laughter to brainwash ponies and powering a city to become an EvilOverlord. He brainwashes her with it and makes her part of his brainwashed harem of mares, raping her repeatedly along with them. When she finally breaks free, she steals his fragment, shoots him in the leg, and leaves him to his KarmicDeath [[DoWithHimAsYouWill at the hooves of his now equally pissed off and unbrainwashed harem]]. She goes back to being herself afterwards, but it shows she's not someone to push too far.
*** [[BadFuture Dark World!]]Derpy is another example. She's still a kindhearted {{Ditz}} and probably one of the nicest mares you could meet, but she's the new Element of Loyalty and has spent the last thousand years walking nonstop around Discord's castle, making her ''very'' strong ''without'' using her new SuperMode. She proceeds to help the rest of the Mane Cast defeat the blackbirds that have spent the last thousand years trying to eat her daughter (who was [[BalefulPolymorph turned into a muffin]]) and send them to Ponythulu's realm to be eaten. Later on, the Valeyard makes the mistake of spending the entire fight with him tap dancing on her {{Berserk Button}}s. The result? [[spoiler:She crosses the RageBreakingPoint and ''[[NoHoldsBarredBeatdown beats him to death]]'' after his [[SoulJar Regeneration Template]] has been destroyed, ignoring his [[VillainsWantMercy pleads for mercy]].]]
*** Shining Armor is a FatherToHisMen and ReasonableAuthorityFigure who was Twilight's CoolBigBro, but getting him ''truly'' clopped off is about as smart as royally ticking off [[Manga/DragonBallZ Son Gohan]]. Not only will he [[IAmNotLeftHanded use every ounce of his power to beat you to a pulp]], his ThouShaltNotKill mentality tends to go out the window when he's in TranquilFury mode [[spoiler:as the Diamond Dog that killed his Uncle in front of him [[HalfTheManHeUsedToBe found out the hard way]]]]. Even just getting ''normally'' ticked off resulted in him [[CurbstompBattle curbstomping a Mammoth Tank]] by systematically destroying all its weapons.
*** Princess Cadence is another example. She's the same nice, lovable person we saw in canon, but the two times she's been ticked off she ended up dishing out a CurbstompBattle to ''cosmic horrors''.
** In ''Fanfic/PrincessCelestiaHatesTea'', Celestia shows exactly why she is a [[PhysicalGod Physical Goddess]] when wild accusations of being an imposter result in her entire staff, the Elements of Harmony, and her own sister trying to exorcize her. [[SeriousBusiness And the whole fiasco was over Celestia lying about liking tea to spare her sister's feelings.]]
** In the ''FanFic/MassEffectTheEquestrianEquation'' series, this is a racial trait of Equestrians and their ancient ancestors, the Equines. They are, and were, friendly, cooperative, and believers in the LastSecondChance. That said, they would and do deal swiftly and with overwhelming force against those who refuse to play nice.
*** It's further backed up by biological instinct; amongst Equestrians, conflict typically takes the form of getting up in each other's face, then a staring contest, and only then in violence if neither backs down. Other races don't get that level of generosity; if they don't back down when the Equestrian starts getting aggressive back, then the Equestrian ''will'' attack. [[spoiler: Dr. Milligan finds this out the hard way and is crushed to death by Twilight Sparkle's biotic powers, then thrown into the heart of an artificial star, for attacking Shephard and trying to commit genocide on the Equestrians in hopes of claiming the technological lore of their ancestors.]]
*** The [[AllThereInTheManual Codex]] describes how the first and only major war the Equines had with another race went down. To put it simply, they ''annihilated'' their enemy militarily, economically, and politically, leaving not a trace behind.
** Cadence in ''Fanfic/TheGodSquad''. She has 1) Made to stallions impregnate each other 2) wiped out a mob of rapists 3) Threatened to sterilize every zebra and thus render the species extinct (after they threaten Shining).
** Celestia in ''FanFic/TheAssassinationOfTwilightSparkle''. Her being a kind and benevolent ruler doesn't matter once you've killed [[LikeASonToMe Twilight]]. Even if you're [[OffingTheOffspring directly descended from her]].
** Raspberry Beryl in ''FanFic/AHairierProblemRiseOfTheFurball''. She is usually rather meek, shy, and averse to talking with ponies due to her DarkAndTroubledPast, but if you threaten to kill (or possess) an innocent pony or threaten (or Celestia help you, HARM) her pet phoenix she WILL try to rip the perpetrator to shreds with her dark magic. [[PrinceCharmless Prince Blueblood]] finds this out the hard way when he [[spoiler: attempts to sabotage her trial by stealing Heliodor and causing the phoenix's emotional trauma to reach a point that his reincarnation cycle is shuffled up one year early. The guards barely reach him in time to allow him and Beryl one last tearful goodbye before he goes up in a burst of flame. In a rage Beryl completely freezes everyone in the room, verbally unloads on a scared shitless Blueblood, traps all of him but his snout in dark crystal, and is only saved from actually killing him with Apple Bloom's [[BigDamnHeroes timely arrival]] and CooldownHug.]]
* {{Fanfic/Uplifted}}, a Mass Effect fic set in the middle of World War 2 features a young Wehrmacht NCO named Heinrich Fuhrmann. Heinrich is a soft spoken, gentle giant, who frequently stammers, refuses to shoot wounded soldiers or the men trying to save them and frequently finds himself duped by his superior officer, Joachim Hoch. However, whatever you do, don't try to shoot him. You might find yourself getting a bayonet in your chest or hit by enough molotov cocktails and machine gun fire to kill a small army.
* [[FanFic/UltimateSleepwalker Sleepwalker]] is usually pretty level-headed. However, if you threaten his HeroicHost Rick Sheridan or Rick's closest friends and family, ''[[PapaWolf you will suffer]]''.
* Hinata in FanFic/AGrowingAffection is as sweet and kind as her canon self, though she does slowly become more assertive. [[spoiler: She kills the immortal Madara Uchiha with a weaponized black hole Rasengan.]]
* Hobbes in ''Fanfic/CalvinAndHobbesTheSeries'' normally [[DirtyCoward flees at any sign of danger]] and is generally kind of a drag. He also doesn't like Sherman, a snooty hamster, and the feeling is mutual. When Sherman pushes him too far in "Remember", he actually attempts to ''kill him'', and likely would have if it weren't for Calvin's [[TimeStandsStill Time Pauser.]]
* Jago from Fanfic/AhArchfall. Nice guy. But at the bare minimum of his power, he flattened three bikers WHILE DRUNK. And if he uses Jupiter...
* In ''[[http://www.fanfiction.net/s/8774066/6/There-s-nothing-like-a-fresh-pair-of-eyes-is-there There's Nothing Like a Fresh Pair of Eyes]]'', student Assassin Catherine Perry-Bowen gets conclusively even with school bully Lucinda Rust after years of humiliation in the sword-fighting class. It helps that her vision and ability to fight have been enhanced somewhat...
* In the HungerGames fanfic ''Fanfic/SomeSemblanceOfMeaning'', heroine [[ShrinkingViolet Vale Whitaker]] is probably one of the most sweet-natured, timid tributes in the Games. She hates the idea of harming another human being. This same girl [[spoiler: lividly stabs another girl in the chest after the latter attacks Vale's district partner Kit]], and after [[spoiler: one of the Gamemakers' mutts kills Kit, Vale goes into what could be described as a berserker rage the next time she sees the mutt, jumping on it and hacking at it until it's dead and she passes out]]. To say nothing of the distrustful snark she unleashes on [[JerkWithAHeartOfGold Obsidian Citrine]], even if he's being perfectly friendly to her.
* In [[VideoGame/TheLegendOfZeldaOcarinaOfTime Li]][[VideoGame/SuperSmashBros nk's]] [[FanFic/NewLookSeries New Look]], the usually sweet and girly [[spoiler:[[Franchise/SuperMarioBros Princess Peach]]]] gives the titular character a DeathGlare once she finds out that he snuck into her room without permission, uses ObfuscatingStupidity to trick Link into dressing up in her clothes, [[spoiler: and finally in part 2 decides to follow up on it by putting him in an AndIMustScream fate for the next three months.]]
* In ''Fanfic/TheLionKingAdventures'', a few of the characters are very sweet. But get on their wrong side and you're in trouble.
** Simba eventually [[spoiler: becomes a vicious killer in Series Five after the death of his parents.]]
** Nala [[spoiler: becomes hell-bent on murdering Simba after the trio disbands in ''Changes''.]]
** Haiba [[spoiler: murders Tama in cold blood when she implies that she's going to rape him.]]
** Tojo [[spoiler: becomes corrupted by the power of Hago's staff in ''Tojo's Tyranny'', thus resulting in the consumption of his soul and eventual death.]]
* ''{{Team 8}}'': Kurenai certainly thinks Hinata might one day snap under her father's mistreatment and abuse and [[TakingYouWithMe kill him and herself]].
* The inhabitants of [[MyLittlePonyFriendshipIsMagic Equestria]] have declared their universe a sanctuary for all those caught up in FanFic/TheInfiniteLoops. That means they will ''not'' tolerate anything severely dangerous or morally wrong, and they have banished visitors to the moon for breaking the rules.
* Asula in ''FanFic/{{Pokeumans}}'' is ''terrifying'' when pissed. She is dangerously strong and has a wicked temper. Oh, and GlowingEyesOfDoom.
** Cameron as well, when he snaps and [[spoiler: becomes a giant evil version of himself.]]
* Part of the CharacterDevelopment of [[CuteClumsyGirl Orihime]] in the Bleach fanfic [[https://www.fanfiction.net/s/5002293/1/A-Protector-s-Pride A Protector's Pride]] is her letting all her pent-up anger out. The firt time it happens she [[spoiler: easily hold off Yammy and takes one of his arms out]].
* Sai in the ''Manga/{{Naruto}}'' fanfic ''FanFic/KitsuneNoKenFistOfTheFox'' is a polite, pleasant high school student who spends his time drawing and painting portraits, including painting his fellow students on his canvas if they ask him. But when four bullies [[BerserkButton destroy one of his paintings]] to intimidate him...let's just say Kakashi had to intervene ''quickly'' to stop Sai from killing one of them, AFTER he'd already beaten the four of them to within an inch of their lives.
* Naruto has two moments of this in [[https://www.fanfiction.net/s/8506540/1/Cry-of-the-Raiju Cry of the Raiju]]. The first time at Jiraya when he discovers information about the Uzumaki clan, that was kept from him his whole life. The second is also a moment of TranquilFury at the [[DidYouJustPunchOutCthulhu Kyuubi of all things]].
--> "I never wanted your power just as much as you never wanted to be within my fucking belly! Our fates sadly have seemingly intertwined, for what purpose can only be known for the future, however, I will not tolerate your behaviour as long as I am like this! I will not be told of my faults and my mistakes! I will not be told I am weak by the creature who himself is weak because he does not understand the meaning of compassion! So as long as you are in my fucking insides, I will expect you to shut up and curl in the fucking corner of your cage, do I make myself clear?!" The young Namikaze said coldly before he turned a full angle and walked away from the cage, leaving a silent, shocked, and aggravated fox.
-->However the blonde paused as his fingers twitched with lightning and he turned and shot a large fully charged bolt of lightning at the fox's face, hitting him directly in his right side and striking a heavy blow on the beast's eye. This had cause Kurama to flinch back and growl in slight anguish as it covered his right eye in anger.
-->"One more thing..." The temperature dropped around Naruto as he gazed back "I do not care if you hate me or want me dead, I don't care at this point, however let me give you one final warning..." His eye glowed a cold azure blue as he stared at the Kyuubi no Yoko. "I don't care if you are a god or a tailed beast, or even the first Hokage himself...you will not talk bad about my father and think that your word will not go unpunished. I will make your life a living hell if you want to boast and degrade the works of the dead and the sacrifices that they had to make in order to keep their world safe just a little more."
* Koushiro "Izzy" Izumi is one of the 3 nicest boys in the Digidestineds. In [[https://www.fanfiction.net/s/27735/1/The-Truth The Truth]] by Cybra, he discovers that [[spoiler: his biological parents were murdered]], is nearly [[spoiler: drowned]] and finally [[spoiler: nearly killed by his parents' murderer in a replica of their "accident"]]. How does our sweet little computer genius react? By [[spoiler: swiping the guy's gun and holding him at point-blank range until he gets the full story out of the guy]]. This not only scares the doctor he's threatening but also the watching Matt. The best part? [[spoiler: The gun didn't have any bullets left and when Izzy is asked why he held the man at gun point if he knew he couldn't shoot him, he replies "I wanted him to know how it feels to be toyed with."]] Moral: Do ''not'' mess with Izzy or the people he cares about.
* Hope from ''Fanfic/HopeComesToBrocktonBay'' is an archetypal AllLovingHero, willing to listen to and accept all manners of people no matter their conduct. She's also perfectly willing, among other things, to hold down an AxCrazy serial killer for summary execution, even if she thinks it DirtyBusiness afterwards.
* In ''Fanfic/FieldOfInnocence,'' TheWisePrince Lu Ten is sweet, polite, and compassionate. But [[{{Fanon}} spirits]] [[OhMyGods help you]] if you ever harm his little cousins and trigger his BigBrotherInstinct.
--> '''Lu Ten''': [[BadassBoast Now you listen to me, Uncle, and listen good.]] If you hurt either one of those kids again, if you say anything to make them feel bad, if you so much as look at them wrong, I will face you in an Agni Kai and ''I will break and humiliate you in front of the whole court.'' I don't care who you are. I don't care if our family is watching. I'll hold nothing back, I will destroy you!
* In ''VideoGame/ChronoCross'' fanfic ''FanFic/{{Fellowship}}'', Guile is a kind and soft-spoken BlackMage who treats his little friends like his children and sometimes sheds TenderTears. However, if you hurt or threaten any of his 'children', he will snap and proceed to pulverize you.
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