Took A Level In Jerkass / Anime & Manga

• Oh Lordy, Nakai from 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. 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. He appears to have a bit of a lecherous streak toward his fellow female assistants, as he's only interested in helping the good-looking ones. After he gets fired due to leaking Nanamine's spot in the ranking to his online consultants, he drunkenly goes over to Aoki's house, intending to hurt her, and nearly gets himself arrested if not for Hiramaru's intervention. He goes back to being an assistant, but he's still far from the good person he used to be.
• Guts from Berserk. After the horrible events of the Eclipse that all but broke him, he spends two years as a Byronic Hero who keeps everyone distant from him and is focused solely on killing as many Apostles as he can as he seeks vengeance against the God Hand and Griffith in particular. It is only after reconnecting with Casca, the only other survivor of the Eclipse, that he begins to grow out of this, but this comes at the cost of harboring a pretty horrific Enemy Within that he needs a new circle of True Companions just to keep in check.
• Suzaku from Code Geass took a huge one during the timeskip, for obvious and rather justified reasons. He never really gets better, and his pain is very apparent, if expressed in the wrong way.
• Due to unexplained happenings during the Time Skip, Hei of Darker than Black has gone from a ruthless Anti-Hero, to a drunk ruthless Anti-Hero with an unwanted Morality Pet. Hei had been nicknamed "Chinese Electric Batman", but unfortunately, he's just "Chinese Batman" since he was Brought Down to Badass.
  • Though he gradually gets better over the course of the season, and is back to his old self by the end powers included.
• Dragon Ball Z:
  • This happens big-time to Vegeta during his Face–Heel Turn in the Buu Saga, where he gives into Babidi's magic for the sole purpose of forcing Goku to fight him. While they are in the middle of a crisis. It's worth noting that in doing this he very nearly causes the world to end, as it leads to the unleashing of the below mentioned Buu.
  • Whenever Goten and Trunks fuse into Gotenks, their worst traits combine to make a Smug Super child whose immature showboating is in stark contrast to the individual children, both of whom at least realize when it's time to get serious.
  • Every time Majin Buu transforms. He goes from the child-like and ultimately misguided Fat Buu, to the cruel and cunning Super Buu, to the batshit crazy Kid Buu. He also becomes stronger the more of a jerk he becomes.
• While Yukiteru in Future Diary did eventually grow a spine and Took a Level in Badass, he also becomes an unknowing asshole at the same time due to 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 call Yukki out before it finally gets through.
• Gabriel DropOut: This is the defining moment for Gabriel, who at the very beginning of the first chapter/episode, was a sweet, hardworking, respectable and idealistic angel who wanted nothing less than to spread as much happiness as she could... until she discovers Video Games a few minutes into the first episode/sometime later in the manga. Next time we see her, she has turned into the rude, lazy, cynical, and apathetic slob she will be for the rest of the series, even going so far as to refer to herself as a Fallen Angel.
• Gundam:
  • A Justified Trope in the case of Tem Ray in Mobile Suit Gundam. He was already a borderline Mad Scientist in the beginning, but the biggest leap into jerkassery happened due to brain damage from oxygen deprivation, which can really screw up your personality.
  • Mobile Suit Gundam AGE, Flit Asuno goes from an idealistic shonen hero to a ruthless dictator who is willing to destroy his enemy "race" without listening to anyone even his son and grandson. To say that he has taken a level in jerkass is an understatement. As well as saying there's a reason.
• Jeanie With The Light Brown Hair: After her mother died Jeanie changed as a person, being bitter and cold to everyone including her closest friends. Her father takes her aside and speaks to her about Angela's death. Jeanie believed he was deliberately hiding her illness from her, but as they had a long talk, she understood his reasons for doing it and forgave him. She then apologized to Stephen, Bill and Robert for taking out her anger on them.
• Linebarrels of Iron: The main character so incredibly straight until even the helpful support character hates him.
• Love Hina: The girls of Hinata House, most notably Kitsune and except Mutsumi, during the story set in the Kingdom of Molmol.
• Magical Record Lyrical Nanoha Force: This is what happens to anyone who's infected with Eclipse (except Touma).
• Arguably, Medaka of Medaka Box. Since 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 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.
• Naruto: Sakura in the fillers. While she started to genuinely warm up towards Naruto, the fillers seem to ignore the poor girl's Character Development for the sake of humor. This got to the point where she started taunting Naruto for his misery in the third movie.
  • Let's not forget Sasuke in canon. He did this twice:
    • When Sasuke recovered from Tsukuyomi, he lashed out at Konoha in general for his being weaker than Itachi and Naruto in specific for his success in getting stronger. This led to him defecting and almost killing Naruto.
    • When Tobi told Sasuke the Awful Truth, Sasuke went from sparing the lives of insane prisoners to casually murdering guards doing their jobs, not to mention almost killing Karin because she was captured by the freaking Hokage Candidate.
  • The aforementioned Tobi, the Masked Man, who is revealed to be Uchiha Obito, having gave up hope on the world and willing to enact the Moon Eye's Plan to trap the entire shinobi in a world created through the Infinite Tsukuyomi, like it or not.
  • Iruka of all people takes one in the sixth Shippuden movie. Set after a battle with Akatsuki, some of the Konoha 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 Pain, not even offering to let him get promoted to Chunin or give him a reason why he can't do that.
• It's stated evolution changes a Pokémon's personality in the anime; this is most noticeable with Charizard. As a Charmander he was overall a nice Pokémon, maybe even one of the nicest Ash owned in the Original Series, but when he evolved into a Charmeleon he stopped listening to Ash and was more violent, and it didn't get any better when he evolved again. After Ash thawed him out when he was frozen by Poliwrath, he regained his loyalty to Ash, and with gradual character development by his reappearance in Unova he was as kind as he was as a Charmander, with only the obligatory flamethrower greeting remaining.
• Puella Magi Madoka Magica: This happened in the backstories of both Kyouko and Homura.
  • Kyouko used to be a relatively cheerful and idealistic magical girl who, like Madoka and Sayaka, once worked under Mami's wing as a kouhai. Her wish was for people to listen to her father, an excommunicated minister whose family was starving. Once her father found out, he killed himself, his wife and his other daughter, leaving Kyouko as the Sole Survivor of the Sakura family. Kyouko survived, but turned into a bitter and cynical girl who's willing to let familiars go free and become witches (which will result in the deaths of innocent people) because the familiars won't give her the Grief Seeds that she needs to keep herself alive.
  • It eventually turns out that in previous timelines, Homura was a glasses-wearing Shrinking Violet rather than the cold and aloof loner that she appears as at the start of the series. She made a wish to be able to redo her meeting with Madoka and, as a result of learning the Awful Truth about being a magical girl and enduring a "Groundhog Day" Loop full of frustration and despair, ended up becoming jaded and cynical.
• Ukyo Kuonji gets hit with this badly during the manga (but not the anime) of Ranma ½. When introduced, she's portrayed as "the sane one" of Ranma's would-be suitors, preferring non-violence in her efforts to win Ranma's heart — her first scheme is to try setting Ryoga Hibiki up on a date with Akane, because if they got together, then she can have Ranma by default and everyone's happy. She then winds up becoming as violent and destructive as Shampoo & Kodachi, getting involved with them in Kick the Dog moments like: trying to assassinate Nabiki when she is Ranma's fiancee, leveling Ranma's family house, and bombing Ranma & Akane's wedding. She also goes from simply being sharp with money to outright exploiting the already-abused Konatsu when he comes to work for her.
• Most of the former NERV officers after the Time Skip in the third Rebuild of Evangelion, especially Ritsuko. Somewhat justified though since the reason everyone is now so hostile towards Shinji is because he almost destroyed the world.
• Chiaki Yoshino from Sekai-ichi Hatsukoi went from 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 he was brutally raped and then suddenly forced the two into a relationship based on co-dependency pretty much made him worse as shown when his relationship with his best friend 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 won't let him live down and generally threw him into The Scrappy territory.
• Amy Rose of Sonic X was initially a kindly bubbly girl with occasional Tsundere mood swings. By the final episodes she more consistently acts as an obnoxious and occasionally outright violent Stalker with a Crush to Sonic, to the point half her allies, and even some foes, are outright terrified of her.
• Tengen Toppa Gurren Lagann:
  • After the Time Skip, Rossiu, now Simon's advisor as head of the human government, becomes rather morally questionable, from going behind Simon's back to force the humans living underground to come to the surface (thereby triggering the apocalypse he was trying to prevent) to having Simon arrested and sentenced to death for treason simply to use him as a scapegoat.
  • Rossiu's girlfriend Kinon goes through this to a lesser extent, since, as his aide, she goes along with his plans regardless of her feelings, and ends up becoming a bit colder after the Time Skip. As a result of this, it ends up driving a wedge between her and her sisters, and Kiyal is rather upset that Kinon didn't come in to visit their sister and newborn niece in the hospital.
• Takeshi Yoshida in Touch (1981) goes from nice fanboy who sincerely admires Tatsuya to arrogant, victory-obsessed prick.
• Canute in Vinland Saga after ascending to the throne.
• Takanashi from Wagnaria!! is suddenly a lot gruffer in the second season. Justified in that dealing with Inami will do that to you. Then inverted in that he becomes super-nice to her with even less explanation.
• Chiba and Maho from Wandering Son Took a Level in Jerkass between the elementary and middle school chapters, though Saori mellowed down and learned to be more pleasant while Maho became more neutral. Saori went through a sort of Trauma Conga Line 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 sister, along with said sibling being transgender; though she's always been depicted as a bully to Nitorin, just not as bad in early chapters.
• This trope happens subtly to Nate Adams from Yo-kai Watch, compared to the video games. Halfway into the series, he becomes less willing to reason with the Yo-kai from a particular segment and more inclined to summon one of his Yo-kai friends to find the way to circunvent their mischievings caused by inspiriting, or outright give them a beating (Jibanyan being his most used choice is an indication), such as his personal beef with Snottle without knowing he created him ^note as one of his snots when he was younger and he never tries to reason to him. Ironically, in the games, fighting Yo-kai is needed to befriend them ^note Only a handful of Yo-kai are befriended automatically as the plot progresses, so to build their collection the player must engage Yo-kai in combat, impress them and/or give them their favorite food to earn their friendship (also, some S-rank Yo-kai like Venoct, Kyubi, Arachnus, Toadal Dude and the Super Hero Yo-kai are only available post-game). The fact that he hates being average ^note so much that he allowed a Yo-kai to lick him everywhere to get prizes and that almost every day of his life is thrown upside-down by Yo-kai themselves has to do with it.
• In Yu-Gi-Oh! GX, this happens to Kaiser in a big way when he becomes Hell Kaiser, as you can tell from the name change.
  • Judai, while he wasn't exactly a Jerkass, did become rather cold and distant to his former friends in season 4.

---