History HeWhoFightsMonsters / AnimeAndManga

* Kurapika from ''Manga/HunterXHunter'' seems to be turning into this...

* ''Manga/{{Hellsing}}'' treats this trope in a very interesting way. Nothing is left to interpretation when Alucard shows clear disappointment and grief over [[spoiler:Father Anderson's decision to turn himself into a literal monster in order to remove Alucard from the world. He fails, but only closely.]]

* ''Manga/OnePiece'': Rob Lucci's belief in "[[KnightTemplar Dark Justice]]" makes him just as brutal and violent as the pirates he's supposed to be protecting the world from; Sanji and Franky even lampshade it after seeing Lucci [[YouHaveFailedMe brutally execute Nero for failure]], outright declaring the so-called "agent of justice" to be more evil than they are.

* ''Manga/VinlandSaga'': [[spoiler:Askeladd is half-Welsh, half-Norse]] and hates the destruction and loss of life the Viking Age has brought to the British Isles. In attempting to find a way to end the Viking Age, he became a viking mercenary commander and eventually took part in the Danish-Saxon War, committing atrocity upon atrocity. Unlike most examples he is fully aware that he's long since been tainted by his own deeds: When someone who can actually build a better world asks why he didn't try himself, [[spoiler:Askeladd]] essentially responds that he was too far gone long before he had the power to change anything, [[NoPlaceForMeThere and any world he'd build would be tainted by his own evil]].

* ''Manga/VinlandSaga'': [[spoiler:Askeladd is half-Welsh, half-Norse]] and hates the destruction and loss of life the Viking Age has brought to the British Isles. In attempting to find a way to end the Viking Age, he became a viking mercenary commander and eventually took part in the Danish-Saxon War, committing atrocity upon atrocity. Unlike most examples he is fully aware that he's long since been tainted by his own deeds, and when someone who can actually help him build a better world asks why he didn't try making an open power-grab himself, [[spoiler:Askeladd]] essentially responds [[NoPlaceForMeThere that he's too far gone and any world he'd build would be tainted by his own evil]].

* In his first appearance in ''Anime/KirbyRightBackAtYa'', Knuckle Joe was consumed by hatred in his quest to get revenge on the Star Warrior who killed his dad. This led him to do terrible things, such as trying to kill poor Kirby who wouldn't even fight back. Then cue the appearance of Meta Knight, who reveals that he was the one who killed his father and [[YouMonster calls him a Demon Beast/monster for the awful acts he committed, as well as his abandoning of reason]]. This was the perfect opportunity for Nightmare, who later turned Joe into a monster that could fire spikes at the cute pink spud. See? Not all monsters are made by Nightmare himself - it's also possible to become one by abandoning reason rather than listen to it as well as living only by hatred.

* ''Manga/OnePiece'': Rob Lucci's belief in "[[KnightTemplar DarkJustice]]" makes him just as brutal and violent as the pirates he's supposed to be protecting the world from; Sanji and Franky even lampshade it after seeing Lucci [[YouHaveFailedMe brutally execute Nero for failure]], outright declaring the so-called "agent of justice" to be more evil than they are.

* MutekiKanbanMusume: When Megumi accuses Miki (a prototype of TheBully seen on fiction, incredible strong and dumb) of bullying her, Megumi is truly surprised when Miki retorts that Megumi is the true bully – by using MaliciousSlander, sabotaging Miki’s work and setting tramps against Miki – a realistic depiction of TheBully in RealLife.

* Kurapika from ''HunterXHunter'' seems to be turning into this...
** [[DarkerAndEdgier More like Gon....]]

* The monster hunters of ''{{Claymore}}'' use [[SuperpoweredEvilSide demonic power]] to increase their fighting strength. If they use too much, they transform and become living examples of this trope. Special note: here, it's more like "'''She''' who fights monsters".

* Aporia is like this in ''Anime/YuGiOh5Ds''. After surviving the BadFuture where humanity was wiped out by the Meklord Emperors, he tried to SetRightWhatOnceWentWrong but barely cared about how many innocents had to die in the process, becoming as much a machine as the things that had caused him so much grief and using the Meklords himself in his goal.

* In ''Manga/{{Berserk}}'', Guts is every bit as cruel and sadistic as the Apostles he hunts at the beginning of the series. He deliberately tortures the Baron and Count in the beginning chapters, and, after fighting with Rosine, doesn't stop trying to kill her even after an innocent girl who was tagging along threw herself in front of him. Currently, the only thing preventing him from completely going off the deep end is [[MoralityChain his need to protect Casca from the monsters he fights]], and, occasionally, [[SuperpoweredEvilSide from himself]].

* In ''Manga/MahouSenseiNegima'', Haruna identifies [[spoiler:Kurt Godel]] as being [[http://www.mangafox.com/manga/mahou_sensei_negima/v30/c270/15.html one of these]]. He ''was'' an undeniable good guy as a kid, only to grow up into a completely manipulative {{jerkass}} little better than his enemy.

** Not just him, but the World Government as a whole. Shortly after Gold Roger was executed, they found out that [[spoiler:he had a child with an unknown young woman]]. Their solution? [[spoiler:hunt every young mother or soon-to-be-mother they believed to be suspect, and kill them and their children]]. Pretty damn cruel. Not to mention [[spoiler:it didn't even work anyway: the young woman who actually was pregnant with Roger's child held off on giving birth for ''20 months'', until the hunt had stopped, leading to her DeathByChildbirth]].

* This happens to [[spoiler: Sayaka]] in ''Anime/PuellaMagiMadokaMagica'', though part of it is due to her despair at slowly [[spoiler: losing the boy she's in love with]], and being powerless to stop it. As she fights more and more witches, she starts to become blood-lustful, reaching the point where she seems more insane than the witches, [[spoiler: even before she turns into one herself]].

** In the ''[[Anime/PuellaMagiMadokaMagicaTheMovieRebellion Rebellion Story]]'' [[spoiler: Homura, who had spent many timelines fighting Kyubey to prevent Madoka's contract, ends up hijacking his plan (and literally becoming a Luciferlike figure) to circumvent the Law of Cycles Madoka created.]]

* Kurapika from ''{{Hunter x Hunter}}'' seems to be turning into this...

* Ian deals with this in ''Manga/ACruelGodReigns''. He struggles with being angered at Jeremy's failed attempts to recover from being a {{Hooker with a Heart of Gold}} and {{Functional Addict}} and falling in love with him, but he worries that if he acts upon either of these, he will become like his {{Archnemesis Dad}} who caused all of Jeremy's problems in the first place.

** The same thing happens in ''Anime/MobileSuitGundamAGE'', [[TearJerker heartbreakingly.]] [[spoiler:Flit has been a [[MessianicArchetype Messiah]] who worked to make humans understand each other while defending themselves against the Unknown Enemies -- until his love Yurin dies in the hands of the child Saachez clone, Desil Galette, at which point Flit lost all his idealism and became a murderous monster just like the UE. It got worse after Yark Dole reveals that the UE are HumanAllAlong, as Flit refuses to recognize them as fellow humans who are also suffering in the hands of the evil Earth Federation.]]

* ''Manga/{{Bleach}}'' gives us Kaname Tousen, who joins the BigBad because he wants to seek "justice." [[spoiler:Turns out all he really wanted was revenge]].

** Rock himself, throughout the series, but particularly during Roberta's Blood Trail where he [[spoiler: develops a sadistic side due to Revy and Roanapur's environment, manipulating major players in the city and gambling with peoples lives, including Garcia, a mere child. Fabiola even states that Rock is now considered by her to be "the biggest number 1 bastard in Roanapur".]]
* In ''Anime/YuGiOhGX'', Judai takes revenge on the Dark World monsters for Johan's supposed death, and ultimately embraces the concept of being evil in order to fight evil, and then proceeds to burn entire villages to the ground, while part of him sits trapped in his own mind, muttering ItsAllMyFault. [[spoiler: It is. If he had not rushed into Brron's castle without O'Brien and Jim, everything would've turned out differently. Well, if he also failed to be so supremely focused on "I'll do absolutely anything to get my revenge, no matter who or what I have to sacrifice." anyways.]]

* Ken, the pilot of Blade Gainer in ''{{Godannar}}'', is one of these. His obsession with killing the Mimetic Beast that killed his wife causes him to mercilessly hunt every Mimetic Beast down, without regard to how much property damage or civilian casualties he causes. [[spoiler:His last words before his death is for Lou to not become someone like him. Lou continues to fight off every single Mimetic Beast alone, but Ken's words prevent her from going down his brutal way.]]

** And the worst part of this all? If he ''wasn't'' willing to sink to that level of depravity, he would have gotten killed a dozen times over. As bad as he is, ''everything else is '''{{wor|ldHalfEmpty}}se'''''.

*** [[spoiler:Speaking of murdering the killer, Setsuna F. Seiei almost crossed this point of no return, too, by trying to kill Ali Al-Saachez, the man who fooled him into murdering his own parents in the name of God. Thank to Marina Ismail's spiritual intervention with CrowningMusicOfAwesome by Kenji Kawai, he was saved from becoming a monster like Saachez in time.]]

* NowAndThenHereAndThere: Poor Elamba. He was so devoted to killing King Hamdo he became as demented and twisted as he was.

* In ''MahouSenseiNegima'', Haruna identifies [[spoiler:Kurt Godel]] as being [[http://www.mangafox.com/manga/mahou_sensei_negima/v30/c270/15.html one of these]]. He ''was'' an undeniable good guy as a kid, only to grow up into a completely manipulative {{jerkass}} little better than his enemy.

* ''{{Hellsing}}'' treats this trope in a very interesting way. Nothing is left to interpretation when Alucard shows clear disappointment and grief over [[spoiler:Father Anderson's decision to turn himself into a literal monster in order to remove Alucard from the world. He fails, but only closely.]]

* Very often in the subtext in ''GhostInTheShell''. Even though he lacks cybernetic enhancements and has no special forces background, Togusa is a very valuable member of the team, as with his former career as a street cop and a wife and daughter at home, he often serves as the voice of reason and urges the others to restrain themselves from using excessive violence and illegal methods.

* In the Meakashi chapter [[spoiler:and by extension the Watanagashi chapter]] of ''VisualNovel/HigurashiNoNakuKoroNi'', [[spoiler:Shion Sonozaki becomes convinced that her family kidnapped and/or murdered her LoveInterest, Satoshi Honjou,]] and starts on a chain of murders of her own to avenge him, culminating in [[spoiler:murdering his little sister when his very last request had been for Shion to protect her. This leads to a HeelRealization and IgnoredEpiphany.]]

* Char Aznable of ''Anime/MobileSuitGundam'' fits this nicely, up until he acknowledges to his sister that revenge wasn't the best idea later on in the series. However, he turns back to being this in ''CharsCounterattack''.

** In {{Gundam 00}}, [[spoiler:Louise Halevy]] becomes this as [[spoiler:she turns into a DarkActionGirl to get revenge for her family's death and the loss of her hand. She ''does'' get to kill the girl who caused her disgrace, but by that point, she's so far gone that her ex-boyfriend, Saji, has to dive over the DespairEventHorizon to stop her from hurting herself any more.]]

** The same thing happens in ''GundamAge'', [[TearJerker heartbreakingly.]] [[spoiler:Flit has been a [[MessianicArchetype Messiah]] who worked to make humans understand each other while defending themselves against the Unknown Enemies -- until his love Yurin dies in the hands of the child Saachez clone, Desil Galette, at which point Flit lost all his idealism and became a murderous monster just like the UE. It got worse after Yark Dole reveals that the UE are HumanAllAlong, as Flit refuses to recognize them as fellow humans who are also suffering in the hands of the evil Earth Federation.]]

* In ''LastExile'', Alex Rowe skates dangerously close to this. Although he never makes the jump into full-out villain territory, his need for revenge against Maestro Delphine and the Guild is all-consuming, and at one point, he [[spoiler:orders his ship to open fire on Delphine's at the coronation ceremony of the new Empress, even though if they did shoot her down, the wreckage would have fallen and killed the new Empress (who is also the closest thing to a friend he has) and the combined leadership of both Anatoray and Disith, shattering the tenuous peace that had just now been established between them. Fortunately, his helmsman, Campbell, countermands his orders, advising the gunnery crews that 'the Captain's not himself'.]]

* In his first appearance in ''KirbyRightBackAtYa'', Knuckle Joe was consumed by hatred in his quest to get revenge on the Star Warrior who killed his dad. This led him to do terrible things, such as trying to kill poor Kirby who wouldn't even fight back. Then cue the appearance of Meta Knight, who reveals that he was the one who killed his father and [[YouMonster calls him a Demon Beast/monster for the awful acts he committed, as well as his abandoning of reason]]. This was the perfect opportunity for Nightmare, who later turned Joe into a monster that could fire spikes at the cute pink spud. See? Not all monsters are made by Nightmare himself - it's also possible to become one by abandoning reason rather than listen to it as well as living only by hatred.