Ace Combat: The Equestrian War takes a darker turn since chapter 7 where Firefly meets Black Star, a griffon who burned her home, killed her parents and destroyed her dreams of becoming a Wonderbolt. Fluttershy is clearly traumatized in chapter 10 after she killed Razor while trying to save Cloud Kicker's life, but that's nothing compared to Rainbow Dash suffering a heart-wrenching Heroic BSOD after being beaten up and betrayed by Gilda. Medley becomes literally broken when Gilda breaks her wings.
Turned Up to Eleven in chapter 15. Two of Derpy's best friends die, with Carrot Top dying in her arms. In fit of grief and rage, she attacks Firefly (who tried to sympathize with her!), but due to Fluttershy's intervention, she calms down. After Derpy leaves to see Dinky, Cloud Kicker, unable to damp her emotions any longer, bursts into tears, scared of hearing about several ponies dying and the scene mentioned earlier. Additionally, she fears her best friend, Lightning Bolt, may die in the war as well. Yes, the most cheerful pony among the main heroines is briefly reduced to a sobbing wreck.
The Dead are Undead has Karin Kurosaki subjected to nightmares unlike anything imaginable. Her world is turned upside down by a Zombie Apocalypse and worst of all Yuzu is shot in the face, right before her eyes. Then it just goes downhill as each new friend she makes dies in horrific ways including having their guts yanked out, being torn to shreds, being eaten alive and also Driven to Suicide.
The Lucky Star/Fallout 3 crossover fic Falling Stars has this in spades. Kagami, Konata, and Tsukasa all get their turns being broken, and it is extremely jarring for anyone who enjoyed Lucky Star to see it happen.
My Little Castlevania has several moments where the main characters get broken. Twilight's brother gets bitten by the Giant Bat and is driven violently insane, Fluttershy's critter friends all go rabid and slaughter each other before going out and attacking Ponyville, and worst of all, Sweetie Belle sees her childhood come to an abrupt and terrifying end.
As they run by a burning building, Sweetie Belle looks aside and sees herself and Rarity there, with their parents. It's a restaurant and everypony is having fun, laughing as the flames around them swallow them whole.
Shooting down the next street, Sweetie Belle looks at Rarity and suddenly she is much younger, and pushing Sweetie Belle down this very street in her stroller she loved so much when she was not even a year old. There is an overturned stroller on this street, and as she runs by, Sweetie Belle looks into the eyes of the zombie stepping over it.
They run by the lake, and Sweetie Belle sees herself and her parents there, feeding the ducks as strange, fishlike monsters jump out and begin to chase her and Rarity as they run by.
Played straighter with the baby T. rexes, albeit with potentially deadly consequences. When the protagonists meet them, they have been separated from their parents and each other, and it's heavily implied that Ludlow flat-out abused them before they were rescued. Then he shoots their father in the face, right in front of them, when he comes to their defense. Deconstructed in that this fills the babies with so much pent-up rage and hatred for Ludlow that the moment they're finally freed, they promptly turn on him and tear him to pieces.
In Stars Above, Kagami goes through this in the 2012 timeline. Tsukasa is killed right in front of her eyes, with her death serving as a Start of Darkness that culminates in the destruction of the entire world.
In The Stars Will Aid Their Escape, Herald does this to Fluttershy through Break Them By Talking during the attack on Canterlot, and also tries it with Celestia and the other Element Bearers (and seems to succeed in Pinkie's case). He also manages to break Twilight by exploiting the fact that if you see him without his mask on, you go insane. Thankfully, everyone recovers by the time everything's done with.
In Checkmate, Vlad puts Danny through one of these. After first injecting Jazz with nanomachines that kill her red blood cells, and only sparing her if Danny leaves behind his friends and family to join him, Danny is forced to live at Vlad's mansion. Due to disuse while there, his ghost powers begin to go out of control, eventually leading to them going completely berserk and forcing Vlad to use a device to short out his ghost powers to get him under control. Due to not only the agony of the powers going wild, but the dream he had throughout the whole thing (it mostly occurred while he was asleep), he ends up backing into a corner and sobbing with terror, ending up in a state that caused even the almost heartless Vlad to ask himself; "What have I done?"
"Danny sat at the edge of the pool, crossed legged, watching carelessly the variety of fishes swimming about in the pool's surrounding aquarium. The tired and defeated expression on his face made him appear as if he had aged several years. There was no happiness or vigor in his eyes, leaving them a dull, lifeless blue. In short, he looked everything a broken hero would; and there was nothing more heartbreaking than that sight."
Daneel Rush, the author of the Tamers Forever Series is absolutely vicious in his psychological torment of Rika. First he expands on her Broken Bird nature, showing that her Jerkass behaviour and suicidally competitive personality is actually due to very low self esteem brought on by her father abandoning her and from being ostracised by her peers in her old school, to the point where she has come to believe that she can't have any real friends and that the only real worth she can ever find for herself is by being the best Tamer. Then Takato comes along and for the first time she finds herself truly able to connect with another human being.(he even helps her reunite with Renamon) But her aforementioned issues nearly lead her to shatter this relationship because she just can't accept Takato being a better Tamer than her which coupled with her fear of rejection, leads her to repeatedly break both Takato's and her own heart because she just can't find peace with herself. It Gets Worse, She finally let's go of her pride and truly fall in love with Takato, but although they share three days of happiness together, it's tainted by the horrible truth that Takato is slowly and painfully dying and there is nothing Rika can do to save him, not even taking on twelve Diaboramon at once in order to protect him. It makes her eventual breakdown as she grieves for his death absolutelySOUL SHATTERING.
And from what's been seen so far, GOSPEL seems Hell bent on breaking her down even further
The Author then proceeds to take this trope to nightmarish levels (Thus continuing a proud tradition) with what happens to Mimi. In short, She is kidnapped, forced to undergo an unwilling abortion, and is left to wander the wilderness as her grief slowly drives her insaneyeesh!!
Forward manages to break River all over again after she started healing at the end of the movie by having both River and Jayne captured and tortured by Niska, effectively undoing nearly a year's worth of mental healing for her.
Or, you know, the plot. Which involves Blaine's stalker Alex, who has a very warped idea of Kurt and Blaine's relationship. In the nineteenth chapter after several background appearances, he kidnaps Blaine, Wes, and David and locks them in his basement. Blaine accidentally got concussed, and has woken up with no memory of this.
In The Ollivander Children, Mark probably gets this worse than any of the other characters. An American Muggle who happens to be in the wrong place at the wrong time, ends up mired in the British Ministry of Magic and charged with the crime of Presuming to be a wizard. He's imprisoned, found guilty, when he goes on the run he faces a Dementor attack, and then his Love Interest is kidnapped, and when he tries to rescue her, he ends up in jail again, which brings us to the start of The Ollivanders At War, where probably even more fun awaits.
The Screams series and Hermione Granger. Take one betrayal to Voldemort (by Neville, of all people). Add Ron's death, then mix in every torture method imaginable for her and Harry, including rape. What you get - well, in her words to Neville as he stood with Harry's wand pressed into the back of his neck: "I'm so looking forward to listening to your cries, Neville. Please fill me up and give me a lot of wonderful screams."
The Takotsuboya K-ON Trilogy, over the course of three interlinked stories, breaks most of the K-ON! cast, though it does give them some hope at the end. Mio's is mostly self-inflicted, Azusa's is the primary focus. Only Mugi escapes relatively unscathed.
The author of Fill the Moonadores this trope and uses it whenever possible. From her own OC, Senayax, who gets it the worst in incidents ranging from being forcibly impregnated by her lover, Zexion, who is also five years older than her and being forced to eat her own grandfather to survive, things like being Driven to Suicide and almost dying after her lover's Heroic Sacrifice after holding him and begging for him to Please Wake Up seem almost trivial in comparison.
After what happens to Demyx, both as a Nobody and as a "somebody," you just want to give the poor kid a hug. While his breakdown isn't as triumphant as Senayax's, trying to clean the castle even as your hands are bleeding, chemical-burned wrecks underneath you is sob-worthy.
And considering that he was emotionally and physically abused from cradle to grave as Myde, when Xigbar finally—finally—snaps, so does the reader. Good thing there's an adorable and Fetish Fuel-laden scene after Xigbar snaps.
Considering Larxene was raped and abused by her husband of three years, and is implied to have had many other abusive relationships, she doesn't really catch much of a break, either. While she's still the same sadistic, snarky Larxene that is recognizable from Kingdom Hearts: Chain of Memories, there's a definite air of Stepford Smiler about her, especially during her rape-based breakdowns.
To sum it up; everyone in this fic has horrible things happen to them. EVERYONE.
The Kingdom Hearts AU fic Lost Boys breaks Sora to pieces, and builds him back up in a twisted mirror of himself. After seeing his home and at least father get forcibly ripped away from him via X-Blade summoning by Ventus and Vanitas(the latter ends up possessing the former) he's hurtled off to Traverse Town as pretty much the only survivor, with his friend, Riku, of the Destiny Islands. Oh, and he's four at this point. Next eleven years he grows up into a mentally unstable teenager who is depressed, angry at the world, anti-social, suicidal, and pretty much everything he shouldn't be. He finally gets a break and life seems to get better: he meets Kairi, starts falling in love with her, gets a steady home for once, mentally recoops a bit. But then he fails to keep his promise to keep Kairi safe and watches her get kidnapped by Maleficent, shortly after nearly dies TWICE and experiences severe pain along with it, then he loses Riku, gets even FURTHER depressed, to make things so much better Maleficient mind rapes him by showing him how he's supposed to be canon-wise, and due to it, along with learning Riku's switched sides, attempts suicide. You think he'd finally get a break, right? NO, He DIDN'T die, as much as he wanted to. He finds Riku, who by now is possessed by Ansem, who "helps" him find Kairi. They later split up again, and when they get back together he ends up nearly losing his heart to keep her safe and experiences unbearable pain in the process. Then, when chasing after Ansem, he gets drawn into an illusion of the islands and breaks down into a maniacally giggling, teen-child psychological mess. Oh, and facing Ansem himself once and for all? He gets so broken, Anti-Form just leaps out and mauls Ansem to death while Kairi watches in horror, and Sora finally just ends up collapsing from the exertion.And this is just the first one.
Later in the sequel, Broken Heroes, you can add Ventus to the list. Ventus has lived in Sora's heart this whole time, and understands EXACTLY where Sora is willing to go with revenge. He feels nothing but regret for his life, and even though he has his spots of hope and happiness, he also feels Terra and Aqua are pretty much gone. He was so guilt-ridden he WANTED Riku to kill him with his own Keyblade when he awoke. To quote the author:
"He is insanely guilt-ridden from the fact he killed so many people and ruined Riku and Sora's lives because of his choice. He just wants to feel like he hasn't screwed up, that people have gotten the justice they deserve. "
And then(much later after several adventures and still getting chewed out by Sora) Ventus is brutally injured by Saďx, who he still believed to be friends with, and ends up dying in Sora's arms still thinking he was unforgiven. He's brought back, thanks to Aqua, gets to see her one last time, then DIES AGAIN. Granted, Sora finally forgives and lets go of his hate because of this- being replaced with just depression and regret -but it's crippling to everyone who witnessed it. Especially Aqua, who goes from badass to broken in an instant.
In Omega Dawn, Both Ruxik, Riku's Nobody, and Maleficent attempted to break Kairi by killing Sora, defiled his body, attacking Destiny Islands, force her to fight a war against the Heartless, including Omegasis, the biggest and most ruthless heartless, who represent all evil, and later told her that they could bring back Sora, in order to make her stab herself with her own keyblade so she would become a Heartless and so, having the ultimate powers of the Princessess of Hearts at their hands. They almost succeeded on making her insane, but luckily, she regained her senses and fought back.
In a prologue story for The Legend of Spyro: Zonoya's Revenge, Ember gets put through this due to her attempts to win Spyro's love. However, it ultimately does end up being for the better, as she realizes that Spyro isn't her true love after all, letting her move on and be with Flame, who really does love her.
Happens to Lauren in Mad World, Trick uses his powers to write that the Garuda will be defeated by a champion (who turns out to be Bo). The Garuda is aware of this, and knows that Lauren will be involved. So it and Thaneutterly destroy her life trying to prevent it. Thane brutally murders 19 of her colleagues/friends in the Congo, and then murders her. She is then brought back by the Fae, is subsequently informed by them she is now their slave, and spends the next 5 years as slave facing their constant racism. Thane returns murders an additional 20 people, who look just like the victims from the Congo (including her) and arranges the bodies in the same manner. He then finally captures her, subjects her to Mind Rape and horrific torture. She is left very broken by all this, and is distinctly unamused when Trick confesses his role in it.
In Motherly Scootaloo, this happens to Scootaloo on a few occasions, but she is recovering.
An interesting example is from After The Gala. It's interesting because of what event from the series, Fluttershy's eruption of anger at the Gala, is turned into one of these. When she calms down and realized what she did, the poor girl is hit with this hard and reduced to a sobbing wreck to the point her friends can't even begin to think of how to comfort her. Thankfully, she's unbroken by her friends and Princess Celestia.
Luna, meanwhile, comes almost completely pre-broken. Her past experiences have left her fearing that her own sister is a monster, causing her to assume the worst about everything she does. The real reason she went on the rampage as Nightmare Moon? A thousand years of solitary confinement left her unstable enough to fall under Celestia's Mind Control, forcing her to play the villain her sister had invented and get the Elements of Harmony unleashed upon her... an action that stripped her of her immortality. Learning that last bit completely shatters what little trust she had in her Celly. (Of course, it's morecomplicatedthan that...)
Hormones chronicles Spike's descent into the depths of depravity. He begins the story like a normal sexually frustrated teenager, and through a series of inviting opportunities, ends up committing some very perverse acts. This culminates in chapter 4 (titled: "Last Resort") where Spike molests Winona and is caught by Applejack. Fearing the consequences, he hangs himself.
In Sunset, Twilight is broken through a series of events that lead to her finding out that she is actually a golem Celestia planned to sacrifice, which causes her to almost murder both Luna and Celestia.
In For Want of a Dawn, The events of Sunset have come to pass, but Twilight is FURTHER broken by being taken to an alternate reality where everyone wants to kill her, including her friends; except for Rainbow Dash, whom she meets in hell after RD was killed by an alternate Twilight. Could be a happy ending except Rainbow is then killed AGAIN.
An author who uses this trope a lot is Kalash93, especially in his War Is Hell stories. See a cute, young, happy, innocent, naive, character? Let the breaking commence!
Welcome To The Brothel is a heartfelt letter written by the protagonist to his mother. By the end, it becomes obvious just how fucked up and broken the war has made him.
Its followup story, Relax, actually shows the "fixing" of a cutie from a shell-shocked mass of nerves into a stable youth. It's implied that the portagonist's sessions with the prostitute keep him sane.
His most triumphant example is Shell Shock. Fluttershy joins the army in order to protect her friends. She is sent into a war and Forced To Watch atrocities being committed. When she finally get her chance to save a single life, she instead chooses to kill an unarmed fleeing zebra to safe her own life. The fic ends with her a sobbing wreck.
The Pony POV Series is notable in that, thanks to Discord, this has happened to every mane and side character in the show! This includes Trixie, who was broken personally by Discord to the point Twilight had to enter her mind and manually free her. Later on, and unrelated to Discord directly, Fluttershy gets broken and turns into a Woobie, Destroyer of Worlds named Princess Gaia/Nightmare Whisper who serves as the second Big Bad.
This happens to Twilight and Rainbow Dash in the Alternate Universe FicRainbooms And Royalty, in which Rainbow Dash is Celestia's student, not Twilight. Since Princess Celestia was in Cloudsdale rather than in Canterlot (as in the show), Twilight's magic rages unchecked until she exhausts herself. The examiners for Princess Celestia's School for Gifted Unicorns admits her because they fear she would be a danger to society untrained. She feels that her cutie mark, which she earned during the fiasco, represents her potential to harm other ponies, rather than her talent with magic. Rainbow and Applejack soon set her straight. Rainbow is broken more than once. First, after Nightmare Moon forces Rainbow Dash, reeling from the loss of Celestia, to publicly plead with her to not brainwash Shining Armor, Ditzy Doo, and two Pegasus royal guards, only to do so anyway and reveal that she only wanted to humiliate the proud Pegasus before Ponyville. The second break occurs when the corrupted Shining Armor reveals that he knew all about Rainbow Dash's crush on him, and that there was never any chance of him reciprocating his feelings, as she was little more than a child to him and because he was already spoken for. Note that despite this, and despite the fic is darker than the show, it not too dark, and remains closer to the show's Lighter and Softer feel than that of a Dark Fic.
Warming Up is an sexually explicit fanfic (the kind with an actual story) where Twilight and Spike starts having a relationship. What was initially a light-hearted (abet with explicit sex scenes) romantic fic takes a dark turn, when Spike is separated from Twilight, then due to him being in heat he starts attracting unwanted attention from the rest of the Mane 6, even getting raped by Rainbow Dash and Pinkie Pie.
Twilight in Pages Of Harmony subjects all her friends to this in order to extract the essence of the Elements from them. And each of them is broken in different, terrifying ways before they die. Even Sweetie Belle and her assistant Spike are subject to this due to being in the wrong place at the wrong time.
Quotidian is one long exercise in Hidan driving Temari to the breaking point by messing with her first mentally and then physically, (She contributes by taking so many stimulant shots her body breaks down and fails * just after* he decides he's not going to kill her yet. It works so well that she ends up attacking her brother Kankurou after hallucinating he's Hidan and then ending up in hospital and under psyche review (which she passes through merit of knowing the correct answers). If Hidan could be seen as a cutie, this could also work both ways as he ends up so obsessed with the idea she can kill him that he breaks down when he finds out she can't, and that his obsession is no sign from his god, just him being a bit of a Stalker with a Crush, even if he doesn't see it himself. Oh and he managed to agonize about betraying his beliefs in order to keep her alive (because he wants her to kill him later, naturally.)
Dark Truth: One night, Luffy is tortured and nearly killed by his crew, who are possessed by the ghosts of a long-dead pirate crew who seek revenge on all captains traveling through their haunting grounds. He survives, but is a lethargic shell of his former self, and his crew can't remember what happened that night. Also contains Squick, horror, And I Must Scream, To the Pain, Fate Worse Than Death, and especiallyEt Tu, Brute?.
One Piece: Parallel Works has AkiChung-Feng, who has been through hell pretty much since she was born. In short, she's born as an illegitimate child, loses her mother to a Soap Opera Disease when she is sixteen, is forced to join the Capricorns with her cousin, Showtarou, so she can get to her aunt's house for her Arranged Marriage, is kidnapped by Kaoru and Mina before their Heel Face Turn and the Baba Yaga, is forced away from the Capricorns to go through her arranged marriage, is almost raped while trying to save Enlai's sister, and she has to face a second Arranged Marriage, which is arranged by her own father. And, then there's the fact that she and Heathcliffe are Star-Crossed Lovers because of Aki's family.
The main OC in thisScream fanfic goes through this. At the beginning of Arc One, she's a happy, if sarcastic teenage girl with friends and a caring family. By the beginning of the final arc, she's just...sad. And a bit mutilated.
For some reason, Jim Kirk is given a Break the Cutie back story to explain his Jerk With A Heartof Gold behavior. Witnessing a massacre on Tarsus IV, child abuse, mentally ill mother, and rape as backstory are all favorite plotlines. There is even a link on the Star Trek fanfic recs to a Hurt!Jim site consisting entirely of fics involving Kirk getting hurt. Chekhov tends to take a lot of pain, too.
Broly's Alternate Character Interpretation in the Fanfic Worthy of Legends had it broken quite a bit ever since he was a child. He was taken by Cooler so he could be raised as a killing machine under Cooler's command, and it is also implied that Broly is really an unwilling grunt of Cooler's army and views several of Cooler's actions as being completely despicable (e.g., forcing females to sleep with him or else he destroys their planet, or destroying a planet shortly after his troops enjoyed themselves). Shortly thereafter, Cooler tries to get Broly angry enough to actually fight him and unveil his strength by murdering his mother in front of Broly. It worked too well, as Broly also ended up giving Cooler a serious injury towards his knee that also resulted in Cooler placing a c-plate on his head. Later on, he was framed by Frieza during the latter's visit to Cooler's ship for murdering two dignitaries in a restroom (worse still, this happened right after Broly was sent to get red wine that was apparently something Cooler was saving up for an occasion, implying that Frieza sent Broly to get the wine specifically so it could match blood), and because of Frieza's control over the courts, he was sentenced to a hellhole planetary prison, specifically to break Broly enough to actually allow Broly to become a psychopathic killer under Cooler's control. The guards also injected him with a drug that acted as a poison that would cause his Ki to rot as a security measure to ensure he doesn't escape, and was denied any instance of a cure. His friend, Sauzaa (who, unlike in the movie, was also secretly against Cooler) also ended up sacrificing himself to save Broly by cutting himself (as his species' blood was necessary to cure the drug). He then goes on a Roaring Rampage of Revenge where he does a No-Holds-Barred Beatdown on Cooler that culminated in tossing Cooler into the core of the planet, before taking Sauzaa's corpse and the director of the prison who was also the half-sister of Cooler and Frieza (the latter because she asked to escape with him, and was implied to have done a Heel Face Turn, although Broly didn't entirely trust her), and it was also implied that the fight as well as his transformation resulted in the planet starting to explode. Afterwards, he went to a planet to free some Nameks who were enslaved by a despot, and eventually murdered the despot quite brutally due to the latter giving off a smirk that was far too similar to Cooler in Broly's mind, which caused Broly to break down.