* Due to unexplained happenings during the TimeSkip, Hei of ''Anime/DarkerThanBlack'' has gone from a ruthless AntiHero, to a ''drunk'' ruthless AntiHero with an unwanted MoralityPet. [[spoiler:Hei had been nicknamed "Chinese Electric {{Franchise/Batman}}", but unfortunately, he's just "Chinese Batman" since he was BroughtDownToBadass.]]
** Though he gradually [[CharacterDevelopment gets better]] over the course of the season, and is back to his old self by the end [[spoiler: powers included.]]
* Guts from ''{{Manga/Berserk}}''. After the horrible events of the Eclipse that all but broke him, he spends two years as a ByronicHero who keeps everyone distant from him and is focused solely on vengeance and blood.
* Canute in ''Manga/VinlandSaga'' after [[spoiler:ascending to the throne]].
* Suzaku from ''Anime/CodeGeass'' took a ''huge'' one during the timeskip, [[BreakTheCutie for obvious and rather justified reasons]]. He never really gets better, and his pain is very apparent, if expressed in the wrong way.
* In ''Anime/YuGiOhGX'', this happens to Kaiser in a big way when he becomes Hell Kaiser, as you can tell from the name change.
* Amy Rose of ''Anime/SonicX'' was initially a kindly bubbly girl with occasional {{Tsundere}} [[BerserkButton mood swings]]. By the final episodes she more consistently acts as an obnoxious and occasionally outright violent StalkerWithACrush to Sonic, to the point half her allies, and even some foes, are outright terrified of her. The [[Franchise/SonicTheHedgehog video games' interpretation]] bordered a little into this trope as well, though it's usually much more toned down.
* Oh Lordy, Nakai from ''{{Manga/Bakuman}}''. When he's first introduced he was desperate to get a manga serialization despite not succeeding in ten years. Through much perseverance he proves himself to fellow manga artist Aoki and the two do manage to start up a serialization. However, once he gets a taste of success it goes right to his head and he starts acting like an arrogant, womanizing asshole, alienating most of his friends and colleagues, ultimately getting himself canceled and decides to quit manga and go back home. [[spoiler:Recently he's returned to the business, but not only is he working for Nanamine, the first unambiguously "evil" rival in the series, but both his appearance and personality have grown even more slovenly and repulsive during the interim.]]
* Most of the former NERV officers after the TimeSkip in the third ''RebuildOfEvangelion'', especially Ritsuko. Somewhat justified though since the reason everyone is now so hostile towards Shinji is because [[spoiler: he almost destroyed the world. It's a lot less justified when you take into account that he didn't know his actions would destroy the world, though]].
* ''Anime/PuellaMagiMadokaMagica'': This happened in the backstories of both Kyouko and Homura.
* Chiba and Maho from ''Manga/WanderingSon'' have taken this in recent chapters. In Maho's case, it might be because she hit puberty.
** To specify, Saori went through a sort of TraumaCongaLine in late elementary. She was becoming increasingly jealous of Takatsuki's friendship with Nitori which lead her relationship with everyone to sour. Eventually she became bitter and aggressive. Maho on the other hand was under stress of having her crush fall in love with her little brother, along with said sibling being transgender.
* ''{{Manga/Naruto}}'': Sakura in the fillers. While she started to genuinely warm up towards Naruto, the fillers seem to ignore the poor girl's CharacterDevelopment for the sake of [[PlayedForLaughs humor]]. This got to the point where she started taunting Naruto for his misery in the third movie.
** Let's not forget Sasuke. He did this twice.
*** When Sasuke recovered from [[MindRape Tsukiyomi]], he lashed out at [[NeverMyFault Konoha in general]] for his being weaker than Itachi and [[ItsAllAboutMe Naruto in specific for his success in getting stronger]]. This led to him defecting and almost killing Naruto.
*** When Tobi told Sasuke the AwfulTruth, Sasuke went from sparing the lives of insane prisoners to casually murdering guards doing their jobs, not to mention [[spoiler:almost killing Karin because she was captured by the freaking ''Hokage Candidate'']].
*** Tobi, the Masked Man, who is revealed to be [[spoiler:Uchiha Obito]].
*** [[NiceGuy Iruka]] of all people takes one in The Sixth movie. Set after a battle with Akatsuki, some of the Konona 11's parents are offering to recommend to Tsunade that they get promoted to Jonins for their efforts. Naruto seeing this goes to him as he's the closest thing Naruto has to a family and asks if he could do the same. Iruka coldly shoots him down and tells him he won't get special treatment just cause he saved the Village from Pein not even offering to let him get promoted to Chunin or give him a reason why he can't do that. Geez Iruka and I thought you loved Naruto like a brother
* ''Anime/DragonBallZ'': This happens to [[{{Badass}} Vegeta]] [[spoiler: after his FaceHeelTurn]].
** Whenever Goten and Trunks [[FusionDance fuse into Gotenks]], their worst traits combine to make a SmugSuper child whose immature showboating is in stark contrast to the individual children, who at least realize when it's time to get serious.
* A JustifiedTrope in the case of [[spoiler: Tem Ray]] in ''Anime/MobileSuitGundam''. He was already a borderline MadScientist in the beginning, but the biggest leap into jerkassery happened due to [[spoiler: brain damage from oxygen deprivation, which can really screw up your personality.]]
* Arguably, Medaka of ''Manga/MedakaBox''. Since [[BiggerBad Ajimu]] has introduced five "''normal''" people to her, Medaka no longer views Zenkichi as someone special to her since he couldn't pass the first trial of a test she gave the normals. Then she actively tries to turn him into her enemy by acting cold and offensive just so she can see value in him again. Kind of sad considering it's a combination of her abnormality and her personality that causes her change like this since she can't understand failure or things from a "weak" perspective. She even goes as far as [[spoiler:using an abnormality that makes her weaker than Zenkichi and goes all out in a fight against him. Since Zenkichi isn't really willing to fight her at this point she mops the floor with him. However the abnormality she used is a "perfected version" of Kumagawa's Bookmaker and isn't meant for fighting, but for allowing the person affected to feel the world from the opponents perspective.]]
* Takanashi from ''{{Manga/Working}}'' is suddenly a lot gruffer in the second season. {{Justified|Trope}} in that dealing with [[DoubleStandardAbuseFemaleOnMale Inami]] will do that to you. Then inverted in that he becomes super-nice to her with even less explanation.
* Chiaki Yoshino from ''Manga/SekaiichiHatsukoi'' went from [[InnocentlyInsensitive bratty but well meaning]] ManChild to immature {{jerkass}}. This might be justified as he's dating his best friend Hatori who is a {{Yandere}} and given that [[spoiler: he was [[RapeasDrama brutally raped]] and then suddenly forced the two into a relationship based on [[LivingEmotionalCrutch co-dependency]]]] pretty much made him worse as shown when his relationship with his best friend [[UnluckyChildhoodFriend Yanase]] is strained given that he fails to understand Yanase's feelings and not only turns him down multiple times in the worse way possible but constantly rubs salt on the wound. It gets to the point that Yanase does call him out on his attitude...unfortunately, it means nothing in the next episode where Chiaki pulls a huge {{jerkass}} moment that the fanbase [[NeverLiveitDown won't let him live down]] and generally through him into TheScrappy territory.
* Almost all the 3-A girls in the Sports Festival arc of ''Manga/MahouSenseiNegima''.
* The girls of Hinata House, most notably [[spoiler: Kitsune]] and except [[spoiler: Mutsumi]], during the story set in the Kingdom of Molmol in ''Manga/LoveHina''.
* ''GundamAge'', Flit Asuno goes from an idealistic shonen hero to a ruthless dictator who is willing to destroy his enemy [[FantasticRacism "race"]] without listening to anyone even his son and grandson. To say that he has taken a level in jerkass is an understatement.
* ''LinebarrelsOfIron'': The main character so incredibly straight until even the helpful support character hates him.
* This is what happens to anyone who's infected with Eclipse (except [[IdiotHero Touma]])in ''Manga/MagicalRecordLyricalNanohaForce''.
* ''Anime/Persona4TheAnimation'' has Chie, Yukiko, Rise, and Naoto in episode 20 when the Investigation Team are staying in the Amagi Inn due to them are still in the hot springs when it's the boy's turn and [[NeverMyFault refusing to apologize to them for the moment, even if it's their own doing]]. And worst of all, [[KarmaHoudini they get away with it!]]
* While Yukiteru in ''Manga/FutureDiary'' did eventually grow a spine and TookALevelInBadass, he also becomes an unknowing asshole at the same time due to [[spoiler:being tricked into thinking he could bring his parents -- and any innocent civilians he killed during the Survival Game -- back to life when he became God]]. Once the truth comes out, it takes five characters to [[WhatTheHellHero call Yukki out]] before it finally gets through.
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