History BewareTheNiceOnes / FanWorks

* ''Fanfic/OnceMoreWithFeeling'': Shinji is usually pretty calm and even glum. But when he faced Sachiel again and thought of everything happening again if he did nothing, he went berserker.

* [[Anime/{{Sekirei}} Matsu]] in ''[[https://www.fanfiction.net/s/8527691/30/An-Incomplete-Potter-Collection Matsu's Sekirei]]'' is something of both a CoolBigSis and [[TheJailBaitWait future lover]] for her Ashikabi Literature/HarryPotter. She also uses her hacking skills to completely destroy the Dursely family. And when Dumbledore and a few other professors arrive to "collect" Harry and bring him to Hogwarts, Matsu reads their minds to learn they plan on taking Harry no matter what and Dumbledore fully intends to have Harry die "for the Greater Good". Matsu spends the entire meeting plastering their faces on every International Most Wanted List she can and planning for their eventual attempted kidnapping/blackmail attempts. Even if that means unleashing the entire Sekirei species (including the violent psychopathic ones) upon the Wizarding World and declaring full-out war.

* Ben Tennyson in ''Fanfic/JojosAlienAdventure'' is the kindest amongst the heroes, being the most averse to killing opponents and also having a severe case of ChronicHeroSyndrome. However, '''NEVER''' assume that he can't be vicious to his enemies if they press his BerserkButton of harming innocent bystanders or his friends, and the imposter Captain Tennile, Forever, Devo, and Rubber Soul can all attest to this. When Rubber Soul engages in his infamous KickTheDog moment, Ben is [[RageBreakingPoint so enraged]] that even TheStoic Jotaro is left unsettled, and he ignores the Stand user's cowardly pleas for mercy at the end of the chapter.

** Vivienne Graham isn't easily angered, but her temper was [[YouWouldntLikeMeWhenImAngry quite something]] when someone pushed her to her limit -- and that was [[ForcedTransformation when she was still human]]! As a [[TwoBeingsOneBody part-Ghidorah]] ArtificialHybrid, her temper is no less fierce, and she has more {{Berserk Button}}s due to her TraumaCongaLine and [[ShellShockedVeteran PTSD]]. Did we also mention her [[ShockAndAwe storm powers]] are fuelled by anger and hate?

* ''Fanfic/{{Quiververse}}'': Quiver Quill is a meek, somewhat nerdy earth pony who's more than happy to keep to himself, and is genuinely nice to those he holds dear. Push him too far, or press one of his BerserkButtons, and there will be consequences. [[AbusiveParent Spoiled Rich]] accused him of being a pedophile and slapped her repentant daughter Diamond Tiara while berating her. Quiver's response was to punch her hard in the face and then nearly strangle her to death.

* The DarkFic ''Fanfic/{{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.]]

[[AC: ''WesternAnimation/{{Luca}}]]

* ''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 "[[https://archiveofourown.org/works/38701785/ Padawan's Return]]", when a time-displaced Ahsoka Tano reveals to the Padme of ''Film/ThePhantomMenace'' that Palpatine is the Sith Lord responsible for the invasion of Naboo, she requires the aid of Padme's handmaidens to stop the young Queen basically charging off to try and kill Palpatine with her bare hands.

** 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.]]

* There are a couple examples in the ''Film/GodzillaKingOfTheMonsters2019'' fanfiction ''Fanfic/AbraxasHrodvitnon'':

** [[TokenGoodTeammate San]] is a real sweetheart towards Vivienne, and he's at least tolerant and curious towards other humans, having always been the least malicious of Ghidorah's [[MultipleHeadCase three heads]] before being cut off from his brother heads and falling under [[MoralityPet Vivienne]]'s influence, and having always been less actively invested than his brothers were in Ghidorah's KillAllHumans mentality and {{onicidal mania|c}}. That having been said, ''God help you'' if you hurt Vivienne, who San dearly considers his sister. At one point, San takes control of his and Vivienne's [[TwoBeingsOneBody shared body]] and, reminding everyone that he used to be part of Ghidorah, he kills several of Alan Jonah's goons in an excessively violent and over-the-top manner that's designed to prolong their suffering for daring to psychologically torment his sister.

** San is a real sweetheart towards Vivienne and is at least tolerant and curious towards other humans, lacking his older brothers' OmnicidalManiac tendencies -- but God help you if you hurt his sister (Vivienne).

[[AC:''Franchise/{{Godzilla}}'']]
* There are a couple examples in the ''Film/GodzillaKingOfTheMonsters2019'' fanfiction ''Fanfic/AbraxasHrodvitnon'':
** Vivienne Graham isn't easily angered, but her temper was [[YouWouldntLikeMeWhenImAngry quite something]] when someone pushed her to her limit -- and that was [[ForcedTransformation when she was still human]]! As a [[TwoBeingsOneBody part-Ghidorah]] ArtificialHybrid, her temper is no less fierce, and she has more {{Berserk Button}}s due to her TraumaCongaLine and [[ShellShockedVeteran PTSD]]. Did we also mention her [[ShockAndAwe storm powers]] are fuelled by anger and hate?
** San is a real sweetheart towards Vivienne and is at least tolerant and curious towards other humans, lacking his older brothers' OmnicidalManiac tendencies -- but God help you if you hurt his sister (Vivienne).
* "[[https://archiveofourown.org/series/2166906 Wild Child AU]]" depicts a world where Godzilla essentially adopts Madison Russell after his battle with the [=MUTOs=] as he assumed her family had died in the battle, resulting in Godzilla and Mothra coming to see Maddie as their child. When Madison returns to civilisation during [[Film/GodzillaKingOfTheMonsters2019 the confrontation with Ghidorah]], she is briefly abducted by a group of soldiers with the idea of selling her to Titan enthusiasts. Although Maddie manages to escape, when Mothra learns what had happened she causes the kidnappers' helicopter to crash, the usually benevolent Titan outraged that those humans dared to harm Maddie.

[[AC:''Franchise/SuperMarioBros'']]
* 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.]]

* In ''[[https://www.fanfiction.net/s/12473449/10/An-Open-Secret An Open Secret]]'', Padme is willing to accept Barris Offee wants redemption and let her be her children's nanny. However, she also warns Barris that if any harm comes to them, her suffering will be worse than anything the Sith could imagine in a thousand years and Barris will only die when Padme finally allows her to.

[[AC:''Literature/SherlockHolmes'']]
* Dr. Watson in ''[[Fanfic/DeliverUsFromEvilSeries Mortality]]'' (along with every other relevant Sherlockian work by the author). Ordinarily, he's the [[NiceGuy nicest guy you'll ever meet.]] [[BerserkButton But you mess with]] ''Literature/SherlockHolmes'', and may the Lord have mercy on your soul, because [[TheLeader John H. Watson]] will ''not''. In one chapter, he's captured a criminal [[JackBauerInterrogationTechnique to interrogate,]] and he plays the DeadlyDoctor trope disturbingly straight and delivers a [[DeadlyDoctor 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.” [[OhCrap Uh-oh.]] We know how well things end for you-not well.
** He most likely [[TranquilFury coldly murders]] the criminal when he [[TooDumbToLive reveals in having playing a part in Holmes's death]] while he [[VillainsWantMercy begs for mercy.]] Yeah, not sure if it's a smart move to do that if a detective's dead.
** Also, let's just say the end result for [[SerialKiller Culverton Smith]] is, well....unpleasant.

* ''Fanfic/{{Aemaeth}}'' has a BreatherEpisode in Chapter 3 where Masumi sees a student counselor to try and find an answer for the nightmares she's been having. This counselor is nice, charming, and tells wonderful and engaging stories over her mother's home-grown tea. [[spoiler:Then it's revealed her PsychicPowers are the source of those nightmares, and things go downhill fast.]]

* ''[[https://archiveofourown.org/works/7088386 Red For Fortune]]'': The normally sweet Marinette gets especially scary when she confronts Adrien about a Mᴏᴅᴇ issue with a fashion spread supposedly inspired by the Lunar New Year, comprised of stereotypical outfits designed by his father, modeled entirely by white people in {{Yellowface}}, ''including Adrien himself''. The fact that [[DiggingYourseflDeeper Adrien resorts to trite defenses of everyone involved rather than even try to comprehend why she's so upset]] ends up [[BrokenPedestal destroying the pedestal]] she put him on by the end of the chapter, and then gets her akumatised.

* [[Anime/NeonGenesisEvangelion Shinji]] in ''[[Fanfic/AlphaAndOmegaFanfic Alpha and Omega]]'' is still the nice, unassuming guy he was in canon, even after becoming engaged to [[Franchise/MassEffect Aria]] [[SpacePirate T'loak]]. He also uses [[KillItWithIce cryo]] rounds in shootouts because it doesn't smell as bad as incendiary rounds and makes for a less messy clean up if you get to the bodies before the ice melts. Aria is slightly unnerved by his reasoning.

** Centauri emperor Kran is seen by some Centauri lords as too soft due his social integration policies and unwillingness to militarily confront the Robotechnology-equipped Earth Alliance, and the Hyach (whose leaders hold a grudge against the Centauri for a renegade Centauri faction using mass drivers on their homeworld during a civil war) are waiting for the right moment to attack and finish off the Centauri Republic while preventing the signing of a non-aggression treaty that would give the League mining rights on the very rich world of Quadrant 7. Then lord Kodiro manages to pass a law that on the long run could potentially lead to a new Centauri civil war, and by the time the emperor is finished showing exactly ''why'' he's the one on the top in [[PlanetOfHats an entire race of]] {{Magnificent Bastard}}s House Kodiro has ceased to exist (and was attacked even by the ''Minbari''. Who knew they were being manipulated but went with it anyway because the information that caused them to attack was true), House Vintari (that caused the mess with Earth Alliance in the first place over their treatment of the Narn civilians) has suffered a defeat so crushing and humiliating that CurbStompBattle doesn't even ''begin'' to describe it, lost its lord and forced to sell the planet, a Hyach armada of over two thousand ships has been annihilated in Centauri space, and the non-aggression treaty that has been signed doesn't include League mining rights and has the League forced to pay for the Centauri moving their ships to ambush the Hyach and to not support them against Centauri retaliation if they tried another stunt like that.

** The Hyach themselves are usually very peaceful. Thing is, their current leaders were traumatized children when the renegade Centauri attacked, and they secretely committed genocide on the other race of their homeworld ([[TheNotSecret as the Centauri won't stop pointing out]]);
** Earth Alliance as a whole is a peaceful power. Thing is, [[EveryoneIsArmed the entire population is armed]] for a reason, they have the most advanced technology bar the First Ones, and they aren't shy about using their superior firepower. Best shown in the orbital part of the battle for Narn, where [=EarthForce=] ships casually ''disabled'' Centauri ships as long as they didn't actually pose a danger to them (such as a squadron of antimatter-powered ships that came out of hyperspace too close to the battlefortress and [[NoKillLikeOverkill was disintegrated by synchro cannon fire]] [[JustifiedTrope so that their antimatter fuel, that actually presented a danger if they rammed or exploded, would be dispered and made harmless]]).

** His old frenemy, Magneto, is also a kind and grandfatherly gentleman who's mellowed out somewhat with age. [[ReformedButNotTamed But he's also, well,]] [[TheDreaded Magneto,]] and ''everyone'' in the know treads cautiously at the mention of his name, with one senior member of the White Council name-checking him as "the greatest terror the world has seen since the Frost Giant Wars." [[spoiler: Something he proves upon his entrance by effortlessly turning HYDRA's colossal vibranium-armoured and Destroyer armed helicarrier to scrap]]. This is best summed up in the sequel, when the Red Room made the spectacularly awful decision to kidnap [[spoiler: his younger daughter, Lorna Dane]], and [[spoiler:Harry, his daughter's godson]] and treat them... poorly.

* 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.

* In ''Fanfic/EchoesOfYesterday'', Taylor thinks Kara is the nicest person whom she has met, with "no a mean bone in her body". Nonetheless, Kara's also hot-tempered, impulsive, super-strong and can't stand bullies, as a Nazi super-villain learned when she threw a truck at him.

* In ''Fanfic/HarryPotterAndTheIcePrincess'', Elsa is kind to everyone from house-elves to the eccentric Luna, but [[spoiler:single-handedly destroys Aragog and his family to stop them being a threat in future, and the only reason she didn't kill Tom Riddle in the Chamber of Secrets was because he didn't have a body she could hurt]].

** Cathy, the Sword of Saint Catherine, is the local JeanneDArchetype. She never raises her voice, and is nothing but polite in everything she does. There are few people she will not offer forgiveness to. [[BreadEggsMilkSquick She also racked up a Dementor kill count firmly in the triple digits in a single battle after the Dementors attacked Harry.]]
* In ''[[https://archiveofourown.org/works/25601596/ Honey and Magic]]'', while Literature/{{Matilda}} is [[Franchise/HarryPotter sorted into Hufflepuff]], and so kind that she even acted to defend ''Draco Malfoy'' when he was turned into a ferret by "Moody", during the Battle of Hogwarts she not only manages to save Tonks' life by confronting Bellatrix Lestrange despite only being a fourth-year, but becomes so enraged that she uses wandless magic to kill three Death Eaters with a mass of improvised weapons (ranging from rubble to crystal balls) after said Death Eaters kill one of her friends.

* ''Fanfic/IfWishesWerePonies'': Twilight is one of the nicest ponies in Equestria, and is a loving, protective adopted mother for Harry. But she's also one of the most powerful ponies in Equestria, and anyone who threatens the life/well-being of her son ''will'' face consequences. Dumbledore learns this the hard way when Harry calls Twilight for help when he runs into danger during his detention in the Forbidden Forest, and she not only brings one hundred of Equestria's finest, but she ''tears'' into Dumbledore for thinking such a detention was a good idea in the first place.

** Interestingly, this trait has been used by other monsters. [[VideoGame/ShinMegamiTenseiIIINocturne Naoki Kashima]]'s [[Franchise/{{Persona}} Shadow]] was crafty and cruel enough to drive him insane at the worst possible moment, turning the Equestrians and everyone else they're friends with (a very large portion of the Multiverse) against him in order to paint him as a relentless monster, when in reality he'd been hanging to his sanity by a thread he was tricked into snapping.
** In a non pony example, we have [[Franchise/SuperMarioBros Princess Peach]]. She is as sweet as can be to almost everyone she comes across. However, what most people forget is that she can fight back if she needs too. Her looper powers build on this. As such, it's not a very smart idea to make her mad as [[spoiler:Grodus]] would learn the hard way.

** In Chapter 11, we see through a {{Flashback}} that after AlphaBitch Sara dumped paint all over her, hurt her brother and then mocked how Chloe's father doesn't love her, this makes her snap and beat up her bully with the very same paint bucket, looking like she's covered in blood and then tell her classmates that if they ever do a prank like that again, she will ''kill them all kinds of dead''.
* ''Fanfic/InkyFuture'' has [[VideoGame/MegaManX X]]. There's a good reason why Dr. Light put him through thirty years of ethical testing. And X is a genuinely nice dude who wants nothing more for everyone to just get along, even in an alien future where humans have gone extinct, but push him too far and that "infinite potential" comes out. [[spoiler:Tartar]] finds this out the hard way after [[spoiler:he blends Artemis, Orion, Iris, Axl, Ayane and Ethan and then gloated about it to X to cause him the most emotional agony possible. X overclocks his systems and proceeds to take apart the Mega Man Killers and Genesis Unit singlehandedly ''all at the same time'', and then ''basically tortures'' Tartar in retaliation, with the only thing stopping him from killing Tartar outright is the overclocking causing his body to give out]].
* In ''Fanfic/{{Interventions}}'', this is demonstrated by Peter Petrelli, Matt Parkman and Willow Rosenberg in particular, as Peter helps Jessica take sadistic preacher Caleb apart to stop him being a future threat while Matt and Willow work together to make sure that Maury Parkman will never terrorise Molly Walker ever again.

* In ''[[https://www.fanfiction.net/s/12512455/12/Lex-Marks-The-Spot Lex Marks the Spot]]'', Lex Luthor/Xander Harris convinces a group of bank robbers that the reason Flash doesn't have any truly repugnant villains in his city is because any time who crosses the MoralEventHorizon, Flash goes back in time and [[RetGone prevents them from being born]], which also wipes out the Flash who went back in time and prevents a paradox. After the robbers drop their weapons and armor to flee in terror, Lex admits to the hostages that he made the whole thing up.

* ''Fanfic/TheManyDatesOfDannyFenton'': Danny IS a nice, easy going guy who treats the girls he dates with respect and consideration... but he also is not someone you want mad at you.

* [[Anime/{{Sekirei}} Matsu]] in ''[[https://www.fanfiction.net/s/8527691/30/An-Incomplete-Potter-Collection Matsu's Sekirei]]'' is something of both a CoolBigSis and [[TheJailBaitWait future lover]] for her Ashikabi Literature/HarryPotter. She also uses her hacking skills to completely destroy the Dursely family. And when Dumbledore and a few other professors arrive to "collect" Harry and bring him to Hogwarts, Matsu reads their minds to learn they plan on taking Harry no matter what and Dumbledore full intends to have Harry die "for the Greater Good". Matsu spends the entire meeting plastering their faces on every International Most Wanted List she can and planning for their eventual attempted kidnapping/blackmail attempts. Even if that means unleashing the entire Sekirei species (including the violent psychopathic ones) upon the Wizarding World and declaring full out war.

* ''Fanfic/APeacefulAfterlife'': Charlie is the classic all-loving, sweet as sugar princess....however she's the princess of 'Hell' and the daughter of a fallen archangel and the first demon, and possessing all the power such breeding entails. When pushed to her limit, Charlie [[spoiler: kills the exorcist's God-Given created with his powers and holds him in place to let Kira's final attack kill him.[[note]]God Given cannot manage to get out of her grip despite Charlie being frozen in time.[[/note]]]]

* ''[[http://www.fanfiction.net/s/3547876/1/When_Summoning_Please_Watch_The_Wording When Summoning, Please Watch the Wording]]'': has both Crowley (the FallenAngel who didn't so much fall as 'saunter vaguely downwards') and his old friend (professionally, a FriendlyEnemy) and [[OurAngelsAreDifferent Aziraphale]], after some wannabe Satanists cross MoralEventHorizon to summon the wrong yellow-eyed demon. Initially, Crowley was just annoyed. [[EvenEvilHasStandards Then he saw]] [[WouldHurtAChild how they'd done it.]] He promptly invokes this with a '[[TranquilFury waxy]]' SlasherSmile, tricking them into summoning Aziraphale, who at first seems merely miffed... then Crowley [[TranquilFury shows them what they did]]. [[BullyingADragon And they taunt him]]. Cue divine wrath and CruelMercy that, as Crowley notes, would have impress some of his colleagues Down Below.

** 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 OriginalCharacter, TagalongKid and ServileSnarker. Then he [[LetsGetDangerous gets dangerous]] when he finds out [[RapeIsASpecialKindOfEvil what happened to his sister.]] He grabs the rapist and shoves his head underwater, fully intent on drowning him. He's fifteen. And this is ''before'' he becomes an EmpoweredBadassNormal.

* The trope is mentioned by name in ''[[https://www.fanfiction.net/s/8913349/1/An-Ounce-Of-Prevention An Ounce Of Prevention]]'', when an enraged Slickis is threatening Zimbo upon learning that the bee monster's taunts caused Ickis to develop bulimia.

* Part of [[CuteClumsyGirl Orihime]]'s CharacterDevelopment in ''[[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 first time it happens, she [[spoiler:easilys hold off Yammy and takes one of his arms out]].

* In ''Fanfic/EverydayLifeWithUltimateGirls'', Makoto Naegi is generally considered one of the gentlest people that one can know, and is an absolute NiceGuy and AllLovingHero. However, he does '''not''' take kindly to seeing those he cares about being threatened in anyway, which also makes him a ChickMagnet, though he is somewhat [[CluelessChickMagnet oblivious]] to this.

** 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.''

* 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.

* Yes, Roy is about the second quietest, most even tempered guy in the station after Mike. But in [[http://www.tbillingsemergencyfanfic.com/ this]] series, you'll be very sorry if you try to hurt his family or Johnny. He *will* get physical and in your face if necessary to protect them.

* When Isabela, Luisa and Mirabel overhear a random villager that they are better off without Bruno in ''Fanfic/HisDaughtersTheMiraclesOfTheFamily'', Isabel has the man strung up with vines and forces him to apologize.

* ''Fanfic/FalloutEuropa'': Austin is a pretty amicable guy and fun to be round and talk to. He's also responsible for nearly a dozen on-screen deaths by chapter 5.

* In ''[[https://m.fanfiction.net/s/5502176/21/ Freedom To The Free]]'', Wash, Kaylee, River and Simon are abducted, enslaved and endure a lot before they’re rescued. Back on the ship, Jayne makes a jerkass comment about Simon, who endured much more than the rest trying to protect them. Wash is about the least threatening guy around. He’s funny, lighthearted and playful. But Jayne pushes him to his RageBreakingPoint and Wash grabs Zoe’s gun and turns it on Jayne.

* 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.

** 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]], lead to him dispatching Beelzebub in a TakingYouWithMe moment.]]

-->'''Ven''': You think Sora’s a baby? Who’s the one who just had a temper tantrum and pushed him in the pool? (''walks up to him'') You think you’re tough? That you’re not afraid of anything? Well let me tell you, that’s a lie. Everyone has fear in their hearts about something. Sora? He nearly drowned two years ago when he got caught in a riptide. You think you would come out of that unaffected?\\

'''Ven''': Sora’s not here right now Zenos. You wanted to meet me so bad? Well here I am. Name’s Ven. I’d say it’s a pleasure, but it’s not. All year you’ve been bullying my little brother. Picking on him and his friends and all for what? A crush? Newsflash, if you like someone the way to their heart isn’t through being mean to their friends! You could have been nice, and we would have welcomed you. (''shakes his head in disgust at Zenos' pettiness'') You’re a bully and a coward Zenos. And if you think I’m going to let this continue you’re wrong. This is the last time you hurt my little brother. And I’ll know if you do. Everything Sora sees? I see. If you so much as touch him, I’ll make sure you don’t get away with it. I’ll tell the teachers, my mothers, and if that doesn’t work? I’ll protect him from you myself. That’s a promise.

** Susanoo seems like a goofball most of the time, but if his family is in danger....

* In the ''WesternAnimation/XMenEvolution'' fanfic ''[[https://www.fanfiction.net/s/8552991/1/XXY-Evolution XXY:Evolution]]'', where most of the characters are [[RuleSixtyThree genderbend]], John Grey (male Jean Grey) is a NiceGuy, LovableJock, and CoolBigBro-figure to some of Xavier's younger students. But pushed too many times, he can use his powers for more offensive attacks. This worries Charlene Xavier (female Professor X) because when she first met 12-year-old John, his mutant powers first manifest as the result of the trauma of seeing his girlfriend (presumably Annie Richardson) run over by a drunk driver, and caused him to develop a darker personality. Charlene [[IDidWhatIHadToDo had no choice]] but to erase his memory of the incident and placed psychic shields around the dark persona, but she fears the shields are slowly breaking down, likely {{foreshadowing}} his eventual transformation into the [[SuperpoweredEvilSide Dark Phoenix]].

* ''Fanfic/{{Uplifted}}'', a 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.

** ''WORLD BEYOND'': When Lila tries to convince the rest of the class that Hawkmoth is ''right'' to blame his latest terror spree on the heroes, and that Ladybug and Chat Noir should just give up their Miraculouses, Adrien furiously calls her out, even swearing at her.

* ''[[https://archiveofourown.org/works/7088386 Red For Fortune]]'': The normally sweet Marinette gets especially scary when she confronts Adrien about a Mᴏᴅᴇ issue with a fashion spread supposedly inspired by the Lunar New Year, comprised of stereotypical outfits designed by his father, modeled entirely by white people in {{Yellowface}}, ''including Adrien himself''. The fact that Adrien resorts to trite defenses of everyone involved rather than even try to comprehend why she's so upset ends up [[BrokenPedestal destroying the pedestal]] she put him on by the end of the chapter, and then gets her akumatised.

'''Marinette''': Gabriel Agreste could have easily turned them down if he had the decency to see that what Mᴏᴅᴇ was doing was wrong. Of course, that would require him to realize that his collection was racist trash, and that Mᴏᴅᴇ clearly wanted to portray racist trash. ''(turning the pages over, with PunctuatedPounding)'' How. Else. Can. You. Explain. This? ''(finishes on a shot of Adrien)'' It wasn't enough that they whitewashed my culture, was it? They also had to deck their white models in yellow face. ''(glaring into his eyes)'' What made you think that this was in any way okay? How can you claim to be my friend and do something like this?\\

** In the alternate version called ''Fanfic/VengeanceOfTheStar'', Twilight is ForcedToWatch as Spike (who she adopted as her son) killed before her eyes by assassins. As a result she becomes Midnight Sparkle, and after capturing her would-be assassins, she makes ''them'' watch as she kills their families. [[spoiler:Though it's later revealed that she faked their deaths.]]

* ''[[http://www.fimfiction.net/story/188223/crystal-affair Crystal Affair]]'' has Cadence. When she she finds out that Shining Armor has been cheating on her, she actually tries to ''kill'' him! Fortunately, Spike is there to keep her from doing anything she'll regret.

* 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).

** GodIsGood in this universe (with the exception of Discord, Morning Star, and some of the [[EldritchAbomination Outer Concepts]]), but ticking them off is a ''bad idea''. LoveGod Venus is kind and all loving, but the punishment she gave the pony that [[MamaBear murdered her son]] (and in the process erased countless innocent beings from existence along with him) involved killing her, reducing her home to a smoldering crater, and then making it so ''no one'' (even the pony herself) could remember her name or what she looked like. Given the sheer amount of damage they caused, it's understandable, but shows clopping off a god doesn't end well.

* ''Fanfic/{{Quiververse}}'': Quiver Quill is meek, somewhat nerdy earth pony who's more than happy to keep to himself, and is genuinely nice to those he holds dear. Push him too far, or press one of his BerserkButtons, and there will be consequences. [[AbusiveParent Spoiled Rich]] accused him of being a pedophile and slapped her repentent daughter Diamond Tiara while berating her. Quiver's response was to punch her hard in the face and then nearly strangle her to death.
* 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.

** [[spoiler:Nagato]], whose canon fate had been averted, is a nice, polite, even-tempered and somewhat shy individual... with the ability to flatten mountains when pissed off. ''Do not'' poke with a stick!

** The climax of her character arc comes when she confronts ''Toneri Otsutsuki'' during the Fourth Ninja War arc. At this point the man has given her plenty of reasons [[ItsPersonal to make things very personal]], including: 1) Trying to kidnap her as a child, 2) Attempting to kill Naruto several times, 3) Wanting to force her and her sister Hanabi to become his wives, and 4) Stealing the eyes of her late father Hiashi for himself. Says a lot that she still gives him one last chance to redeem himself by joining them against Akatsuki, but after he refuses and states his intentions to let the war rage on and eventually hijack the Ten-Tails' power for himself, she finally decides he's crossed the MoralEventHorizon, and battles him to the death, ending him with a chakra arrow to his chest that causes him so much pain that his final sound is a ''terrifying'' scream of agony.

* ''Fanfic/ACrownOfStars'': Shinji is generally soft-spoken, calm, non-confrontational, and is also [[TheAtoner a Atoner]] who doesn't want to hurt or kill people. But he's also got a [[TheBerserker very primal, very]] ''[[TheBerserker violent]]'' side to his personality that comes out whenever his BerserkButton get's hit too hard. Harm Asuka and he will go from “I don’t want to kill anyone” to “I want to make them ''BURN''!!” Much of his character development in the latter half of the fic deals with coming to terms with this side of his personality.
* ''Fanfic/AdviceAndTrust'': Shinji is pretty quiet and meek. However when [[spoiler:Leliel trapped Asuka into its body]], he forced his Eva into a berserker, roaring rage and ''shattered'' and tore to shreds its body.
* ''Fanfic/TheChildOfLove'': It took a lot to make kind, non-confrontational Shinji snapping... but after his father Gendo [[spoiler:nearly got Asuka killed, schemed to turn their baby daughter into a war weapon]] Shinji was most ''unhappy''. Finding out Gendo had lied to him about burning all his mother's pictures was the last Straw. Shinji marched in his cell, called him out on everything and said he wanted nothing to do with him anymore and that would be their final conversation (understand Shinji is usually ''terrified'' of his father).

* ''Fanfic/{{HERZ}}'': Shinji hates violence and killing and he fervently wishes being a good person, husband and father. And part of his definition for that means being there for his family and protecting them. And he will shoot whoever threatens them.

* 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.]]

* ''7teen: Fanfiction Series'': Jonesy's father, Michael. Quite possibly the nicest guy you could imagine, [[BreakTheCutie especially considering all the hell he and his sons faced from when his first marraige ended to when he married his second wife]]. But if you dare insult his kids ''or'' his integrity in any way, you'll regret it faster than you can say "sorry".

* In ''FanFic/StarWarsLineage'', Qui-Gon is presented as being his usual AllLovingHero self, extraordinarily compassionate to every living being and patient with his SarcasticDevotee Padawan. But harm Obi-Wan or Tahl, and you will suddenly realize that this is a man who was trained by ''Dooku.'' He very nearly falls to the Dark Side when confronting [[DeadlyDoctor Jenna Zan Arbor]], and when a WellIntentionedExtremist Jedi Master essentially {{Mind Rape}}s Obi-Wan, Qui-Gon's flat, cold response is as follows:

* 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]].

* ''Fanfic/CoOpMode'': As of the ''Grave Lord'' omake, James is revealed to be capable of being between this, GoodIsNotSoft, and KnightTemplar. In that alternate possibility, alone and without [[Literature/{{Worm}} Taylor]], James ends up [[spoiler: single-handedly disabling and capturing each and every hero in Brockton Bay while scaring the villains badly enough to keep away while he does it to save Taylor.]] However, in the omake he doesn't avert GoodIsDumb for forgetting that he could've done it with less violence.

* 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.

* A common theme in Creator/{{Vathara}}'s works is that she believes "Beware the Nice Ones" is a contradiction; if you're nice, you ''can't'' be dangerous, and if you're dangerous, you can't be purely nice. "Nice" people need "less-nice" people to protect them, because the idealism that builds thriving societies is incompatible with [[IDidWhatIHadToDo the actions necessary]] to protect those societies from harm. Any [[TheParagon paragon]] in her works who attempts to do ''both'' has to either accept that darkness as part of themselves or [[TheParagonAlwaysRebels go stark staring mad]].
-->[[https://www.fanfiction.net/s/5398503/30/Embers Katara]] is [[FanFic/EmbersVathara not honest]]. [[WesternAnimation/AvatarTheLastAirbender Katara]] is sweetness and confidence and "we're going to help Aang save the world!" Until she runs into [[BerserkButton something she doesn't like]], at which point the Sugar Queen cracks, and a lot of nastiness oozes out. ...Yeah. That relationship is going to end ''[[SarcasmMode so well]]''. I think I'll take my chances with [[LawfulEvil Azula]]....
* [[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.

* In the ''Series/{{Smallville}}''/''Film/TheFastAndTheFurious crossover ''[[https://www.fanfiction.net/s/9472416/1/On-the-Run On the Run]]'', after Letty has spent some time helping Clark deal with some personal matters after he saved her life, once she reunites with Dom she compares Clark to a mix of Brian and Vince; he's generally a kind man, but once someone angers him he's a very dangerous person to cross.

* In ''New Look'' Series: ''[[VideoGame/TheLegendOfZelda Link]]'s 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]].

* Leni Loud is generally considered the nicest of her sisters but in ''[[https://www.fanfiction.net/s/12320880/1/Mall-Rats Mall Rats]]'', when she figures out that some jocks she and Lincoln run into at the mall are bullying her brother, she literally beats the stuffing out of them with skills she taught herself after [[LiteralMinded taking the expression "fight or flight" literally]].

* [[LightNovel/TheFamiliarOfZero Princess Henrietta]] in ''[[https://www.fanfiction.net/s/11288478/2/The-Floating-Castle The Floating Castle]]'' shows the people of [[LightNovel/SwordArtOnline Aincrad]] why she's in charge after learning Albion has fallen to Reconquista and her beloved Wales is dead, by [[CurbStompBattle grinding a Floor Boss to death with a tornado made of water]]. In her words upon hearing of a monster even stronger than the one Kayaba [[HeroicSacrifice died fighting against]], "How wonderfully convenient. [She] had really been looking forward to a bit of violence today."

[[AC:''LightNovel/TheFamiliarOfZero'']]

[[AC:''WebAnimation/{{RWBY}}'']]
* ''Fanfic/RubyAndNora'': '''Pyrrha'''.