History KnightOfCerebus / AnimeAndManga

** Currently quoted in the main page. Kurumi Tokisaki is merely a peek of what the true darkness is in this story. Once [[BigBad Sir Isaac Ray Peram Westcott]] [[spoiler:starts meddling with the protagonists, the story becomes more than just a race to seal the most Spirits and also bringing the story to a darker path.]] This takes two stages. When he and his minions start take actions against the protagonists, he reveals various plot threads that has been foreshadowed since the beginning (Phantom's involvement with the Sephira Crystal) as well as new ones (Inverse Spirits), and things get serious. And then, numerous horrific 18+ incidents happen when he is around; from torture of teenage girls, rape of Spirits and mutilation scenes. The story that was suppose to light-hearted with numerous jokes and funny moments becomes a living hell. This continues up until Volume 13, when [[spoiler:he finally gains one of the Spirit's Qliphoth Crystals, and becomes an Inverse Spirit himself]], where he ups the ante by taking actions himself. Not only do things go FromBadToWorse pretty fast, he even shows us in Volume 16 how ''easily'' [[spoiler:he can end the plot by simply killing Shido in the middle of his everyday life]]. Volume 19 takes the cake [[spoiler:when he steals Mio's powers to become the Second Spirit of Origin]], giving him the power to control the death and existence of all creation. Until the end, every appearance of Westcott was played 100% seriously and left his mark as the most heinous villain in Light Novels' history.

** Currently quoted in the main page. Kurumi Tokisaki is merely a peek of what the true darkness is in this story. Once [[BigBad Sir Isaac Ray Peram Westcott]] [[spoiler:starts meddling with the protagonists, the story becomes more than just a race to seal the most Spirits and also bringing the story to a darker path.]] This takes two stages. When he and his minions start take actions against the protagonists, he reveals various plot threads that has been foreshadowed since the beginning (Phantom's involvement with the Sephira Crystal) as well as new ones (Inverse Spirits), and things get serious. And then, numerous +18 incidents happens when he is around; from torture of teenage girls, rape of Spirits and mutilations scenes. The story that was suppose to light-hearted with numerous jokes and funny moments becomes a living hell. This continues up until Volume 13, when [[spoiler:he finally gains one of the Spirit's Qliphoth Crystals, and becomes an Inverse Spirit himself]], where he ups the ante by taking actions himself. Not only things get FromBadToWorse pretty fast, he even shows us in Volume 16 how ''easily'' [[spoiler:he can end the plot by simply killing Shido in the middle of his everyday life]]. Volume 19 takes it to the cake [[spoiler:when he stole Mio's powers in order to become the Second Spirit of Origin]], giving the power to control the death and existence of all creation. Until the end, every appearance of Westcott was played 100% seriously and left his mark as the most heinous villain in Light Novels' history.

* ''Manga/BlackCat'' is normally about Train and his friends going on adventures to capture criminals as sweepers, but whenever [[BigBad Creed]] is introduced, things get dark really fast for Train and his friends.

* Much like its SpiritualSuccessor ''Claymore'', ''{{Manga/Berserk}}'' is nothing short of a DarkFantasy series. However, the TV series is considerably LighterAndSofter than its manga counterpart, so for the majority of the [[PragmaticAdaptation TV series']] run, it was basically composed of Guts and Griffith talking about dreams and ambition, the Hawks battling the Tudor Empire for the Kingdom of Midland and a bunch of political stuff, and developing characterization that wasn't derailed by {{Adaptation Induced Plothole}}s or AdaptationExplanationExtrication. But when Nosferatu Zodd was introduced with his prophecy halfway through the series, followed by the introduction of the [[BigBadDuumvirate Godhand]] toward the end [[spoiler: especially the transformation of Griffith]], we knew that this series was going to [[DownerEnding end on a bad note.]] Within the manga itself, the Skull Knight, despite not being a villain, manages to be this since whenever he shows it, tends to mean things will get bad.

* While the series maintains an episodic MonsterOfTheWeek format even after her appearance, the addition of [[spoiler:Northa]] to the cast of ''Anime/FreshPrettyCure'' marked the arrival of a far stronger villain who was also dead serious about her intentions. [[spoiler:Even the monsters of the week got stronger (thanks to her new sorewatase seeds).]] After [[spoiler:Northa]] came the Dark Precure of ''Anime/HeartcatchPrettyCure'', a villain who makes her mark by defeating the veteran Cure Moonlight in her first appearance. Every other appearance pushes Cures Blossom, Marine and SixthRanger Sunshine into corners until Moonlight gets back into the saddle.

* ''Anime/HappinessChargePrettyCure's'' Phantom, the "Pretty Cure Hunter" is this. Unlike [[spoiler:Northa]] or the Dark Precure, Phantom actually ''defeats'' Pretty Cure, depowering them, trapping them in crystal mirrors and shoving them in what appears to be a ''graveyard''.
* Whenever the Master of Synapse appears in ''Manga/HeavensLostProperty'' you can be sure the series will turn darker.

** Though [[spoiler: Kyubey]] may very well be the ''biggest'' example in the series; The girls’ main enemies, Walpurigsnacht and her [[WitchSpecies fellow]] [[EldritchAbomination witches,]] are {{Generic Doomsday Villain}}s, while Kyoko and Homura [[spoiler: [[HiddenDepths aren’t all that bad]]]]. Almost all the antagonists in the series, including [[spoiler: [[WasOnceAMan the witches]]]], are sympathetic {{Anti Villain}}s. [[spoiler: Kyubey]], by contrast, is the ''only'' character to be portrayed as [[TheSociopath wholly]] [[MoralEventHorizon irredeemable]], making them an evil presence that is [[NightmareFuel frightening]] in a way the other villains are not.

** The pilot movie ''Anime/YokaiWatchShadowsideTheReturnOfTheOniKing'' has its BigBad, the titular Oni King: Rasen. Easily the vilest and cruelest villain in the entire franchise, as him being the true leader of the Onimaro, he feeds on the malice of humans accumulated by them to become more powerful, simply for his own amusement. He's also no pushover, [[spoiler:as he easily brushed several attacks of the heroes' Yo-kai friends and even ''Enma and Zazel'', and it took the combined efforts of [[FusionDance Yami Enma]], several element-vielding Yo-kai, and Touma with the Fudou Raimeiken to destroy him, and he became ''dangerously close to killing two main characters'', as heavily wounding Natsume and throwing her to a river to drown to death -- only to be timely saved by Azure Dragon -- and cheap-shotting Touma with a blood dart upon being decapitated before finally being put down for good, effectivelly killing Touma; the boy would have stayed dead if not for [[MookFaceTurn the three Onimaro]] who he truly befriended pulling an HeroicSacrifice to get him better]].
** The series has Haruya Sakami/[[spoiler:Shutendoji]] and his two underlings, Fukurou and Douketsu. His goal of obtaining the Youseiken (one of which being the Fudou Raimeiken held by Touma) and finding "the Princess" in order to take over the Youmakai leads him to order Fukurou to try to locate her by blowing darts coated with a malice-enhancing toxin at humans, thus turning them in some form of Wicked, as well as forcing some Yo-kai to their Shadowside forms; having his Dragon Douketsu stall the heroes (which Douketsu does rather efficiently -- cementing himself as an example of this trope -- as the heroes never truly score a victory over him, [[spoiler:and in one ocassion he even puts Suzaku, one of Akinori's strongest Yo-kai, close to death]]), and using a human fortune-teller (which he later [[YouHaveOutlivedYourUsefulness nonchalantly depowers]]) [[spoiler:to lure Touma to a trap in order to seize the Fudou Raimeiken and ordering Fukurou to dispose of him, which he luckily fails.]] Fukurou himself has proven to be this when, [[spoiler:Haruya [[YouHaveOutlivedYourUsefulness coldly deeming him useless]] causes him to lose it and try to prove his worth by using the Fudou Raimeiken to turn into a [[EvilCounterpart dark version of Fudou Myouou]] and truly giving the heroes a run for their money, and with Soranaki's influence, he gets an OneWingedAngel form which proves to be quite powerful for even Douketsu -- which as a fighter and Haruya's Dragon, that's saying enough -- and it takes Touma attaining a SuperMode for Fudou Myouou to put him down for good]]. All of the above comes to a head when [[spoiler: Shutendoji has Keisuke kidnapped in order to ramsom the Youseiken, and when Natsume and co. naturally come to rescue him, he and Douketsu [[CurbStompBattle ''easily'' steamroll]] several of the Yo-kai they summon, like Jibanyan, Komasan, Micchy, Junior, Azure Dragon, Blazion, and Blizzaria; and it took the Soranaki suddenly appearing and prompting Natsume briefly awakening as the Princess, Shuka, in order to subdue it, ironically putting Shutendoji several steps closer to his goal.]]
** [[spoiler:Jorogumo]] easily qualifies, as [[spoiler:she made the first KnightOfCerebus do her bidding, making him look like a LaughablyEvil villain and thus playing him as a fool by taking advantage of his quest for the Princess -- and only Douketsu knew she was toying with him and tried to tell him, to no avail.]] [[spoiler:She used Ayame Himeno as her vessel, all while the poor girl barely suspected anything, and blended with the detective agency all while none of them didn't even suspect anything (especially Akinori, who had a crush on Ayame at first sight), killed a MonsterOfTheWeek who just underwent a HeelFaceTurn and ordered Haruya to do the same with another one.]] [[spoiler:When she reveals herself thanks to Haruya, she puts him and Douketsu out of commision rather easily and mops the floor with Jibanyan and ''Fudou Myouou Ten'' forcing the heroes to retreat.]]
** The aforementioned [[spoiler:Soranaki]] is shaping to be an example of this trope, if ''[[Anime/YokaiWatchForeverFriends Forever Friends]]'' is an indication. He is [[spoiler:an AncientEvil which nearly drove the Yo-kai race to extinction, and he coincidently awakens in the setting of the film (the 1960's), transforming Shien into Maou Shien, prompting Lord Enma and Susanoo, Tsukuyomi, and Amaterasu to move out to stop him]]. He [[spoiler:resurfaces after 90 years, spreading [[TheCorruption a Virus which makes Yo-kai hostile by tapping on the wickedness on their heart]] [[PowerBornOfMadness and converting it into power in their Shadowside forms]]. [[spoiler:He was the one who turned Fukurou into Shinmagunjin Fukurou, forced Shuka to awaken within Natsume, and corrupted Douketsu, forcing Shutendoji to kill him]]. He eventually became so powerful [[spoiler:that he infected several of the heroes' Yo-kai friends and ''Kaira'' in a full-scale assault]], and [[spoiler:the Youseiken which were supposed to awake Shuka? They were instead the key to awake ''him'' instead!]] [[spoiler:It took Natsume and her friends fully awakening into Shuka and her retainers, the efforts of several Yo-kai, and a new Fudou Myouou, to defeat him for good.]]

** Diavolo manages to stand out even among the other candidates due ''[[Manga/JoJosBizarreAdventureVentoAureo Vento Aureo]]'' ''already'' arguably being the darkest entry yet due to this story showcasing a lot more intense bruality in its fights, the death count being higher than ever before, and the moral ambiguousness of every character involved, ''especially'' its protagonists. However, ALL of that gets permanently turned UpToEleven the minute Diavolo gets fully involved in the story, with his [[KinslayingIsASpecialKindOfEvil true intentions being revealed]] and how his Stand, [[TimeMaster King Crimson]] comes as less of a typical FightingSpirit the readers come to expect in ''Jojo'', and more of an pure murder machine when it attacks.

* ''Manga/FruitsBasket'' begins as an adorable, lighthearted series that follows a cute high school girl who befriends a lot of pretty boys who transform into adorable animals... until [[BigBad Akito Sohma]] makes her debut and it's revealed that she's abused all of the Zodiac members in various horrific ways, both physical and mental. In direct contrast to other cases of DoubleStandardAbuseFemaleOnMale that are PlayedForLaughs (like Kagura being clingy towards Kyo and beating him up in fits of passion, or Uotani regularly picking fights with Kyo unprovoked), ''nothing'' Akito does to the Zodiac members, as well as any "outsiders" who butt in, is meant to be funny in the slightest. Every time she's on-screen, any comedy or light-hearted vibes virtually disappear.

** Jellal is the first villain who poses a serious threat to the cast's lives, and is trying to return [[UltimateEvil Zeref]] himself, as opposed to the various demon's Zeref created that have been sought out in earlier arcs, or power skirmishes that have otherwise been the focus. In addition, while previous tragic backstories have been about losing or fighting with family members, his and Erza's past is full of all kinds of slavery, torture, and betrayal. After Jellal, every arc is some serious threat that will either kill the cast or destroy the country.

* ''Manga/FruitsBasket'' begins as an adorable, lighthearted series that follows a cute high school girl who befriends a lot of pretty boys who transform into adorable animals... until [[BigBad Akito Sohma]] makes his [[spoiler:(actually [[RaisedAsTheOppositeGender her]])]] debut and it's revealed that he's abused numerous members of the Sohma family in various horrific ways, both physical and mental. In direct contrast to [[{{Tsundere}} Kagura's]] [[DoubleStandardAbuseFemaleOnMale abuse of Kyo]], '''''nothing''''' Akito does to the Zodiac members, as well as any "outsiders" who butt in, is PlayedForLaughs in the slightest, and every time he's on-screen, the comedy and humor virtually disappear.

** ''Anime/DigimonSavers'': [[spoiler: Kurata]]. Before he had appeared the only real "dark" parts of the anime resulted from Gotsumon's incredibly hostile attitude toward Ikuto/Keenan. When [[spoiler: Kurata]] arrived, he brought genocide (including the deaths of both of Ikuto/Keenan's "parents", resulting in genuine TearJerker scenes) and singlehandedly made the season the darkest one yet. For once we had a genuinely evil [[spoiler:''human'']], and also BY FAR the most evil character ever to grace the franchise.

* ''Anime/{{Pokemon}}'':

* ''Manga/RosarioPlusVampire'' MonsterOfTheWeek formula progressively stopped being the ''main'' formula due to these three:
** Kuyo and his student police force, [[spoiler: who beat up the UnwantedHarem and actually ''killed'' Tsukune; this was the first time he was injected with blood, and also caused the first instance where Inner Moka was in any real danger.]].
** Ruby's master helped the transition along, in an arc that [[spoiler:focused heavily on FantasticRacism, which has since become one of the series' most prevalent themes. She was planning to wage war on humanity, and was willing to cut down her own adopted daughter to do so]].
** Midou and the outcast monsters, [[spoiler: who beat up ''Inner Moka,'' killed Tsukune ''again,'' and caused this next blood injection to put the Evil in SuperpoweredEvilSide.]] After this incident, the main theme of FantasticRacism between humans and monsters, and between monsters and other monsters, really began to take over.
** The second season manga started out mostly silly and comedic; even the first serious villain, the doppleganger, had his own share of silliness. Then, in volume 3, we meet Miyabi, whose first act is to sexually harass Mizore, as well as steal her first kiss. This is NOT PlayedForLaughs, as the molestation destroys her emotionally, ultimately making her [[spoiler:''attempt suicide''. Fortunately, she was saved by Kurumu]]
* ''Manga/{{Trigun}}'':
** Legato Bluesummer's introduction changes the tone in a single frame. It's a bright and sunny day, the kids are playing with Vash. Then out of nowhere, Legato. He killed and ate the friendly shopkeeper Vash was just speaking to, and feels it would be a downright shame if the little girl Vash just bought an ice cream for would have to be next. The entire scene is completely horrific, but what cements it as this is the opening shot of the usually lighthearted and goofy Vash looking legitimately terrified for the first time in the series that clearly indicates exactly how bad things are about to get.
** Monev follows Legato's cue and begins shortly afterwards - while previously Vash was always able to stop the villains before they can do serious harm, the guy basically moves down everyone in his path (including women and children) to get his target - and he actually enjoys this collateral damage. This is also the first time that Vash really loses it, and comes close to killing Monev.
* ''Manga/RurouniKenshin'' has actually two of these:
** The first one is Udo Jin-e. The series had started rather lightly... and in came this [[EvilIsHammy loud]] BloodKnight with a permanent SlasherSmile, an until-then-unseen degree of cruelty, the capacity of either killing you bloodily or putting you in an [[spoiler: AndIMustScream]] position, and the dubious "honor" of showing us some glimpses of what would happen if [[spoiler: Kenshin ever fully reverted to his Battousai side.]]
** The second is Saitou Hajime. His introduction signaled the arrival of the Kyoto Arc (and the much more dangerous villain Shishio) whereas previously, the series had been a light-hearted action comedy where, a few serious villains like the aforementioned Jin'e and Aoshi aside, Kenshin's everyday life continued as a light-hearted and comical romp.

** Devimon in the original ''Anime/DigimonAdventure''. While the first few episodes of the show were simple MonsterOfTheWeek, his appearance in Episode 8 introduced a proper, intertwined story arc and highlighted that the show wasn't kidding around anymore. It got somewhat lighter - though with even more MythArc - in the short 'Etemon arc' - only for Myotismon and the Dark Masters to firmly seal the series in CerebusSyndrome.

* ''Manga/SoulEater'' started off as a zany series with a very eccentric cast. Then [[MadScientist Medusa]] shows up with her abused and unstable child Chrona, and releases [[EldritchAbomination Asura]], which causes the series to take a much darker turn. People start dying and going insane and the zany imagery became more nightmarish. Asura himself qualifies as any time he appears the comic relief stops completely. At least Medusa still had some humorous scenes.
* ''Manga/ZatchBell'' tends to get a lot of these; because most of the enemies tend to be fairly goofy, it's jarring when you get someone like Zofis who's playing for keeps.

** Mercenary Tao continues the trend. He is the first serious villain in the series with no humorous qualities to him (of which even General Blue had some), and he causes the first major on-screen deaths in the saga--which was actually quite shocking back then due to how lighthearted the manga usually was.

** [[EvilCounterpart Goku Black]] is the first such example for ''Anime/DragonBallSuper''. While Frieza was the first technically malevolent antagonist of the series, his arc was lighthearted and threat diminished by Whis and Beerus' presence. Goku Black is played more seriously- his first act bringing Future Trunks' Earth to the brink of extinction and setting up a darker tone for the series. Unlike Frieza, who simply wants to rule the universe, Goku Black is an OmnicidalManiac who wants to eliminate all life across the multiverse and has one of the highest body counts in the franchise

* ''Anime/MazingerZ'' has a weird example in Count Brocken. To put it simply, he is the first villain to harm (and actually kill) innocent people. And apart from that, he proceeds to do some horrible stuff. He is so notable amongst the villains that, in this very wiki, he is the most notable person that is mentioned when the darker parts of the show are talked about (complete with creepy design than the already creepy Ashura). Yet, in the same chapter he appeared, he provides some of the [[SugarWiki/FunnyMoments most hilarious moments]] in the entire series in a rather stupid way. Its kinda hard to think he’s the same character who first kills on-screen.
* ''Manga/NegimaMagisterNegiMagi'':
** Fate Averruncus from the manga. His first appearance saw him petrifying a bunch of people and essentially defeating the party (who had been putting up a good fight up to that point) all on his own. When he appeared a second time he averted BloodlessCarnage by [[spoiler: [[ImpaledWithExtremePrejudice impaling Negi with a hunk of stone]] and scattering everyone across the world]]. This was the trigger that eventually led Negi to begin using BlackMagic. Oh, and Fate's ultimate goal is [[spoiler: to erase the magic world from existence, [[OmnicidalManiac along with everyone in it]].]]
** Evangeline serves as an earlier example. Once it's revealed that not only is she a vampire with a PowerLimiter curse that also binds her to the school, but the one who cursed her was Negi's father, and she needs Negi's blood to break it, the series started its GenreShift from harem comedy to shonen.
* ''Franchise/LyricalNanoha'':
** Fate Testarossa served as this, shifting the focus away from the standard GottaCatchThemAll, MonsterOfTheWeek, MagicalGirl format upon arrival and eventually sending the plot careening towards [[TheFederation a more interdimensional scale]].
** [[EvilMatriarch Precia Testarossa]]. ''Nanoha'' really went dark when [[KickTheDog she was introduced]]. How exactly ''was'' she introduced? [[spoiler:Beating (the clone of) [[DarkMagicalGirl her daughter]], with a whip for not gathering ''every'' MacGuffin.]] After she left, it became slightly lighter again for the later two seasons.
** At least until Jail, in [[Anime/MagicalGirlLyricalNanohaStrikerS the third season]], mentioned that he had all of the Numbers (functionally, and sometimes biologically, ''[[ParentalIncest his daughters]]'') impregnated with clones of himself.
** The Huckebein from ''[[Manga/MagicalRecordLyricalNanohaFORCE FORCE]]'' took the series to a new level of dark, effortlessly beating the heroes in just about every appearance.
** Chapter 48 of ''Manga/MagicalGirlLyricalNanohaVivid'' finally has Fabia Crozelg taking center stage [[spoiler: by effortlessly taking out around half of the ''[=ViVid=]'' cast, including Einhart and Sieg.]]
* Mukuro Rokudo from ''Manga/Reborn2004'' is an example of this trope; in the beginning of his story arc, a number of major characters are badly beaten, the anime gets much gorier, and elements like the zombie-like mafia jailors and MindControl are introduced. His appearance also signals a major GenreShift in the series, which had been comedic until this point.

* ''Manga/{{Naruto}}'' always had relatively darker antagonists as the series progressed.
** [[MasterSwordsman Zabuza]] and [[AnIcePerson Haku]] are the first in a series. The villains before them were an easily-defeated JerkAss intending to use Naruto and [[DesignatedVillain Ebisu]], who's played for laughs and mostly harmless. The moment they show up, it's clear they intend to kill their opposition in cold blood.
** [[AxCrazy Gaara]]. During the Chunin exam, things always gotten darker and bloodier whenever it focused on him, from start to end. Until Orochimaru came in, Gaara was permanently the most ruthless and savage (constantly wanting to see people bleed), and the only Chunin exam villain without any comedic traits, or even moments of comedy at all.
** While previous examples was intimidating, [[MadScientist Orochimaru]] brings the first present [[KilledOffforReal death]] of a main protagonist, helps send TheLancer into serious SanitySlippage and was playing for keeps.
** [[AloofBigBrother Itachi Uchiha]], [[{{Deuteragonist}} Sasuke's]] older brother, is also one. First thing we learn about him is that he killed the entire Uchiha clan save Sasuke for reasons of his own, then abandoned the village to join [[StandardEvilOrganizationSquad Akatsuki]]. When he first appeared in Konoha with his partner Kisame to capture Naruto, he and Kisame easily defeated Kurenai, Asuma, and Kakashi, sending the last in hospital. When Sasuke heard his brother was in the area, he immediately rushed out to challenge him, but Itachi easily beat him and {{Mind Rape}}d him in the process, further feeding Sasuke's inferiority complex.
** And when [[TheDragon Pain]], the leader of Akatsuki, appeared, things really become darker. In his first appearance, he kills one of the most influential mentors to Naruto, Jiraiya, and then single-handedly destroyed the Leaf Village, and brought Tsunade to a coma. He also killed numerous named characters, such as Shizune and Fukasaku, led Kakashi to his death, and nearly killed [[LivingEmotionalCrutch Hinata]] [[ForcedToWatch right in front of Naruto]] after she [[AnguishedDeclarationOfLove sincerely confessed her love to him]], though these came [[BackFromTheDead reversed with his redemption]], other than [[KilledOffForReal Jiraiya]].
** But the biggest example in a series is [[BigBad Tobi]], [[spoiler:aka [[FallenHero Obito Uchiha]]]], when was revealed that he is the mastermind behind the Akatsuki and that he was responsible for the Nine-Tails' Attack on Konoha. It's taken even further when his next appearance brought in a whole new villain competency level, as he initiates the war on the horizon with his entire army of Expendable {{Mooks}} at his command, in addition to former, undead comrades, each of which is an S-rank criminal, including his own Six Paths of Pain made out of former Jinchuuriki; with the Gold and Silver Brothers who are mini-Jinchuuriki in their own right with the treasured tools of the series PhysicalGod in their possession, in addition to summoning the Demonic Statue of the Outer Path that doubles as a tank and the container for the nine different EldritchAbomination. And it's taken UpToEleven when [[spoiler:he revives the Ten Tails and takes his under control and turns the table of CurbStompBattle against the Alliance by beginning a methodical attack against the Allied Shinobi, nullifying every jutsu they use against him, and he even summons the tree form of the Ten-Tails and has it absorb the chakra of nearby ninja, taking their chakra and killing many, thus using this rising death toll to shatter the determination of the Shinobi Alliance.]]
** [[PredecessorVillain Madara Uchiha's]] arrival on the battlefield turns the table against the Alliance from a swift victory of hope to a losing CurbStompBattle of despair. His complete revival quickly reverts all that the heroes fought to achieve and puts both of the protagonists at death's doorstep.

* [[EmbarrassingFirstName Pantyhose Tarou]] was only the first of a succession of very serious, very powerful foes in ''Manga/RanmaOneHalf'': while earlier opponents were always ineffectual antagonists versed in wacky, fun, harmless MartialArtsAndCrafts tournaments, Ryugenzawa's {{Orochi}}, [[KiManipulation Prince Herb of the Musk Dynasty]], [[TheDrifter Ryuu Kumon]], and ThePhoenix King Saffron followed in Pantyhose Taro's footsteps by forcing Ranma & Co. into more serious, no-nonsense combat, where death was suddenly a very real possibility.

* ''Anime/PrincessTutu'' starts off as a fairly light, straight-up GottaCatchEmAll MagicalGirl series for the first few episodes. Then [[DarkMagicalGirl Princess Kraehe]] steps in and '''''BAM!''''' -- here comes the GenreShift.
* Depending on if we're talking about the manga or the anime of ''Manga/RozenMaiden'', either Barasuishou or Kirakishou counts. It should be noted in Kirakishou's case that when [[spoiler:the most [[CheerfulChild cheerful and childlike character]] in the whole franchise [[ImAHumanitarian gets eaten]] by her]], you know there won't be much more comedy. Barasuishou on the other hand [[spoiler:both directly and indirectly causes the deaths of all the other characters deliberately just to please her father, Enju, a jealous apprentice to Rozen]], and with her dead serious attitude that everybody must participate in the Alice Game, it is not very surprising.
* ''Anime/{{Pokemon}}'':
** Butch and Cassidy be headed for this at their first appearance, complete with an eviler sounding Team Rocket Motto. It didn't last long, but at least other members of Team Rocket manage to stay properly intimidating -- especially when they show up in force. Even Max admits that the cast is pretty lucky that they usually only have to deal with the TerribleTrio that stalks them around.
** Pokémon Hunter J surpasses them in malevolence, being the darkest villain to ever appear in the series and to never suffer from VillainDecay, not to mention being one of the few characters that was actually [[spoiler:(seemingly) killed off]].
** Another example is Sabrina, who popped up earlier than Butch and Cassidy and before J did. Sabrina only appeared for two episodes, and after her arc everything returned for normal, but for years later, no villain surpassed Sabrina in terms of scariness[[note]]Even though Sabrina was closer to a WoobieDestroyerOfWorlds, as it is implied that she was incapable of controlling her psychic powers before Haunter came along[[/note]].
** Cyrus of Team Galactic intended to destroy the entire world and everyone with it (even the other members of Team Galactic) while possessing Azelf, Mesprit, Uxie, Dialga, and Palkia to create a new dimension for him to rule. [[spoiler: And he apparently dies in the episode right after J.]]
** [[spoiler: Lysandre, Xerosic, and Team Flare in ''XY and Z''. Lysandre is notably a rare example of a villain who tricks a protagonist into working for him. The Evil Malamar are also petty terrifying, and episodes featuring them tend to have little or no humour.]]
** Some of the villains from the movie series are these, including [[Anime/PokemonTheFirstMovie Mewtwo]], [[Anime/{{Pokemon3}} Molly Hale]] [[WoobieDestroyerOfWorlds (inadvertently however)]], [[Anime/Pokemon4Ever the Iron-Masked Marauder]], [[Anime/PokemonArceusAndTheJewelOfLife Marcus]], and [[Anime/PokemonZoroarkMasterOfIllusions Grings Kodai]].
* ''Manga/PokemonAdventures'' was all fine and dandy until Giovanni popped up. Similarly ''Manga/PokemonDiamondAndPearlAdventure'' had mooks and the mildly threatening Admins such as Saturn or Mars, but it got dialed up when Cyrus came around.
* ''Manga/TheElectricTaleOfPikachu'' was a lighthearted ComingOfAgeStory (Although still DarkerAndEdgier than the anime it was based on) until the Black Fog appeared, which can basically be considered a SerialKiller in Pokemon due to it having drained the souls of people and Pokemon alike meaning it has killed dozens.
* ''Anime/YuGiOh'':
** Yami Marik. Contrary to the original Marik he was ''not'' content to hide in the shadows relying on minions and trickery, he would personally duel and make his opponents writhe in pain in the Shadow Games he inflicts on them. In both the original Japanese and the English dub, Marik was focused on Yami Yugi and only saw his friends as pawns to be used to get to him. Yami Marik on the other hand didn't care who he faced, he would make them suffer and eventually MindRape them when they lost. He also underwent an EvilCostumeSwitch, trading in Marik's BareYourMidriff pink shirt for a sleeveless black one with a BadassCape, the Eye of Ra was permanently displayed on his forehead, his hair was suddenly spiking into the air, and his voice is deeper with [[VoiceOfTheLegion an echo effect]].
** Yubel in ''Anime/YuGiOhGX''. After [[AmbiguousGender their]] appearance, IdiotHero Juudai starts his downward spiral, [[DeathIsCheap characters start dying]] and some of the standard humor in the series begins to disappear as the it takes its turn towards full DeconstructorFleet territory. Even in 4Kids GagDub which made the season LighterAndSofter compared the Japanese version, Yubel has no comedic quirks.
** The Three Tenors in ''Anime/YuGiOh5Ds''. While the full extent of their plan isn't revealed for some time, when they first began to appear they rolled out the Meklord archetype and sent Yusei into a HeroicBSOD when suddenly the iconic Synchro monsters of the series that almost all the duelists rely on became useless, forcing them to re-evaluate their strategies in addition to the mystery of the new villains that had rolled into town.
** Kiryu also counts for ''5Ds''. He's an old friend of Yusei's who was a gang leader in the past and is shown killing a police officer in flashback. He died in prison with his heart filled with hatred towards Yusei. When he first appears, his Earthbound Immortal makes its debut by eating the souls of the people on the battlefield, and he hands Yusei his only onscreen defeat.
** Vector in ''Anime/YuGiOhZEXAL''. His first appearance marks the start of the Barians taking matter into their own hands. When he shows up again later, he reveals he's been pretending to be Yuma's friend for an entire arc, causing a HeroicBSOD and a brief rift between Yuma and Astral. After his defeat, his response is to wake up the evil god of the Barian World, solely so he can keep screwing with Yuma and Astral.
** ''Anime/YuGiOhArcV'':
*** There's a non-villain example, although it takes a while before the "non-villainous" part is proven. Kurosaki's arrival is marked by him turning several innocent people into cards (a metaphor for death), being all-around sneaky and violent, and having the strange ability to make duel-monsters real. The CerebusSyndrome hits in full when he duels the BitchInSheepsClothing, unmasking [[spoiler: him]] and subsequently revealing that the real KnightOfCerebus villains have been HidingInPlainSight all along. Kurosaki himself is a ProperlyParanoid AntiHero whose pervious actions were part of an [[WellIntentionedExtremist extreme yet understandable plot]] that could have potentially saved countless lives if he hadn't been misinformed on the current situation.[[note]]Twice. He first thought his targets were part of the genocidal army that destroyed his home. After learning the truth he continued to card people in order to lure out Reiji Akaba, hoping that Reiji could be used as a hostage to force [[BigBad Leo Akaba]] to stop the invasion and return all prisoners. For context, that's 10-20 people Kurosaki carded in an attempt to save something between thousands and millions of lives. After learning that Leo Akabar doesn't give a shit about his son ''and'' [[ArchnemesisDad that Reiji was planning to wage war against Leo]], Kurosaki joined forces with Reiji and became a full AntiHero.[[/note]]
*** Yuto also applies, having the same backstory as Kurosaki, frequently appearing alongside him, and being [[MrExposition the exposition guy]] for [[WhamEpisode some pretty dark information]].
*** The Obelisk Force and Yuri, who fully live up to this trope by carding no less than 15 people without hesitation in their first appearance.
** Spectre of ''Anime/YuGiOhVRAINS'' takes PlayerKilling into a whole new level when [[spoiler:he subjected Aoi/Blue Angel into a [[{{Sadist}} sadistic]] ColdBloodedTorture and a horrible MindRape before ending the duel with a [[TheReasonYouSuckSpeech "The Reason You Suck"]] BreakingSpeech]].
* ''Anime/NeonGenesisEvangelion'' was a dark series, but the events of the "Action Arc" (from Asuka's arrival up to Ireul/Eleventh Angel) were relatively light-hearted, with Misato and Kaji making amends, Shinji starting to gain some confidence, finding a family and friends and having a BelligerentSexualTension relationship with Asuka. Then came Bardiel/the Thirteenth Angel, and everything went to Hell.
* In ''Manga/TheWorldGodOnlyKnows'', when Fiore shows up, she starts off as a cute IneffectualSympatheticVillain working behind the scenes. [[spoiler: Then she crosses the MoralEventHorizon by trying to [[BoomHeadshot snipe Kanon/Apollo]], and succeeding in stabbing them.]]
* ''Manga/MedakaBox'' once was a lighthearted, comedic series about school adventures of a GodModeSue and her harem. After 14 chapters of that, the first serious antagonist, [[KnightTemplar Unzen Myouri]] appeared, heralding oncoming GenreShift into a fighting series with a brutal bloodbath (no one supposedly died, but a ton of people probably were put in hospital for years). And just as the arc, started by Unzen's appearance was about to end, Kumagawa Misogi stepped on the scene, signaling a lesser shift to even more DarkerAndEdgier tone.
* ''Anime/RingingBell'' is all cute and adorable until the Wolf appears and the mood becomes very dark.
* ''Anime/PuellaMagiMadokaMagica'':
** The series looked like it was going to be another typical magical girl show, albeit one with unusually dark undertones. Then came Episode 3, which introduced Charlotte, the third Witch. The moment when she [[spoiler:ate fan favorite and CoolBigSis Mami alive]] was the moment when the series showed just how dark of a {{Deconstruction}} of the genre that it could be. And this was only a taste of [[FromBadToWorse what would come later]].
** Unusually for this trope, [[spoiler: Charlotte is defeated shortly after she killed Mami.]]
** The first episode introduces four out of the five main girls, three of which are shown to be genuinely nice and kind-hearted people, and the fourth of which is somewhat mysterious and jaded. All other humans are similarly nice, normal people. Then one episode after Charlotte, we're introduced to a fifth magical girl, a psychopathic JerkAss who threatens to hunt down and ''kill Sayaka''. That's Kyoko Sakura for you, folks. There's a ''reason'' why she didn't appear back when the show was pretending to be a typical MagicalGirl show. [[spoiler: She [[CharacterDevelopment gets better]] and gets a FreudianExcuse, too.]]
** Happens again with a heroic character in ''Anime/PuellaMagiMadokaMagicaTheMovieRebellion''. As soon as Homura [[spoiler: discovers that she and her friends are in a witch barrier]] and takes off her glasses and hair ribbons, the movie's tone shifts from a faux-TastesLikeDiabetes parody to a sinister mystery. And [[spoiler: she makes the movie even darker ''again'', near the end, when she performs a FaceHeelTurn, becomes a self-proclaimed demon, and then takes over the universe after her friends rescue her, instead of just ascending to magical girl heaven]].
** The SpinOff manga ''Manga/PuellaMagiKazumiMagica'' has [[spoiler: Yuuri]]. Another unusual example because she only took the role in the fourth chapter, having appeared as a MysteriousWatcher in the first two and an easily defeated antagonist in the third. But in the fourth, [[WhamEpisode hoo boy...]]
** All this is ironic because the story's real villain [[spoiler: Kyubey, appears from the start and looks like a cute and harmless sidekick and only later in the series is his true dark side revealed]].
** Though [[spoiler: Kyubey]] may very well be the ''biggest'' example in the series; The girls’ main enemies, Walpurigsnacht and her [[WitchSpecies fellow]] [[EldritchAbomination witches,]] are {{Generic Doomsday Villain}}s, while Kyoko and Homura [[spoiler: [[HiddenDepths aren’t all that bad]]]]. Almost all the antagonists in the series, including [[spoiler: [[WasOnceAMan the witches]]]], are sympathetic {{Anti Villain}}s. [[spoiler: Kyubey]], by contrast, is the ''only'' character to be portrayed as [[TheSociopath wholly]] [[MoralEventHorizon irredeemable]], making them an evil presence that is [[NightmareFuel frightening]] in a way the other villains are not.
* ''Manga/{{Claymore}}'' never made any pretenses to be anything other than a dark series, but whenever [[BigBad Priscilla]] turns up, things are going to go south very, VERY fast.
* Mag Mel from ''Anime/{{Bakugan}}''. Previous villains were dark, but Mag Mel is by far the most terrifying villain yet with an extremely dark storyline. He was [[SealedEvilInACan imprisoned for genocide]] and that's before the series ''even started!'' Once he appeared, he {{Mind Rape}}d Dan and Drago in a very horrific manner. Once he was finally free, he started trying to burn Gundelia to the ground. In scope of sheer evil and darkness, he's the darkest and most horrifying villain in the entire series!
** And then the second arc of that season introduces [[EldritchAbomination Coredegon]] who plans to murder the Bakugan for [[DisproportionateRetribution rather trivial reasons]] and subverts every trope associated with anime in general. He's also the only antagonist to [[spoiler: kill both a human and a main character]], even if [[spoiler: this is undone via SetRightWhatOnceWentWrong]].
* ''Manga/{{Bleach}}'' has a few examples.
** [[MadScientist Mayuri Kurotsuchi]] is one of the most vile and depraved characters in the series, being responsible for the agonizing, torturous death of countless quincies including Uryu Ishida's grandfather, conducting experiments on living subjects and making use of human bombs (Who were [[BadBoss his subordinates]], by the way)- even exploding one of them just because "a bomb isn't supposed to come back". Even when his interests aligned with the heroes, he showed zero remorse for his crimes.
** [[BrokenAce Sosuke Aizen]] has gallows humour. He's willing to let Tousen cut off Grimmjow's arm just for the fun of it. His reaction to seeing comic relief unfold is to wonder whether or not it's a bad strategy to take him off of his guard. Even before he's revealed as a villain, an extended flashback shows Shinji commenting on how uptight he is.
** [[GodEmperor Yhwach]], TheEmperor of the [[PuttingOnTheReich Vandenreich]], is single-handedly responsible for taking ''Bleach'' into a darker direction than it has ever been. Aizen gets freed from prison to fight him. You know how bad one KnightOfCerebus is when you have to bring in the previous one just to fight him. [[spoiler:Yhwach decimates the Gotei 13, kills Yamamoto and any Quincies he has no further use for, defeats the Royal Guard, and tricks Ichigo into killing the Soul King. He then absorbs the Soul King and remakes the Royal Realm in his image.]]
* The entire first episode of ''LightNovel/CubeXCursedXCurious'' seemed to be setting up for a lighthearted SliceOfLife comedy series. Episode 2, enter: Peavey.
* ''VisualNovel/HigurashiWhenTheyCry'' seems like a light-hearted harem comedy until BigBad Oyashiro-sama is introduced. A dark, vengeful demon god that the citizens of [[TownWithADarkSecret Hinamizawa]] live in fear of, he begins to cast a dark shadow over the whole plot, bringing forth a HatePlague and MilkmanConspiracy to menace Keichii and his friends- and he does all this ''[[HiddenVillain without even being seen]].'' [[spoiler:Subverted when it turns out [[SamusIsAGirl she’s]] TheScapegoat.]]

* ''Anime/TigerAndBunny'' has several, each one putting the series deeper into much darker territory:
** Lunatic - VigilanteMan, first to kill somebody in the series. Whenever he shows up, things starts turning grim. [[spoiler: He has a DayInTheLimelight in episode 16, probably the most depressing episode in the entire series]].
** Jake Martinez - while Lunatic was treated seriously, he was at least a WellIntentionedExtremist, while Jake [[spoiler: held the entire city hostage, and sent the main character and four of his friends to the hospital]] ForTheEvulz. He was the first villain who was shown to take pleasure in evildoing.
** [[spoiler: Doctor Rotwang and Cis]] from episode 15, who have been indirectly responsible for starting a chain of [[TearJerker heartbreaking moments]] that prevailed through the rest of the series.
** And finally the BigBad [[spoiler: Albert Maverick mindraping Barnaby in a scene strongly reminding of date-rape scenario, being the first to murder non-villainous cast member and framing Kotetsu for it]].
* [[EldritchAbomination Space]] [[StarfishAliens Monsters]] from ''Anime/{{Gunbuster}}'' - for the first two episodes series is lighthearted and funny, being basically [[SportsStories sport story]] with [[RealRobot mechas]] and serious elements were nothing more but backstory. Once the first battle has come, it turned into desperate fight for survival and stayed that way even after the shift to the SuperRobotGenre.
* ''Anime/{{Diebuster}}'' starts as sympathetic and optimistic [[SuperRobotGenre Super Robot]] MonsterOfTheWeek show, but after one of [[spoiler: true Space Monsters, the same ones as in Gunbuster]] shows up, things go to hell very fast.
* ''Anime/PhiBrainPuzzleOfGod'' played with this - new villain, Herbert Müller, didn't started the shift to more serious tone. In fact his appearance stopped one that was already taking place, by putting delay on plans of previously established villain [[spoiler: Rook]], who resumed them after Müller was out of picture and became Knight Of Cerebus himself.
* It's interesting to watch the increase of the power of the villains in ''Manga/OnePiece''.
** Alvida and Morgan possessed no real threat to Luffy, and Buggy wasn't really much of a challenge either. Afterwards, Captain Kuro and Don Krieg were much more menacing, but still relatively weak: They were just bad guys who happened to show up at the time. Everything changed when Arlong came along, and while the series retained its light-hearted tone for the most part, seeing what the stakes are when a real monster gets involved changed the world of the series forever. Follow this up with an enemy Luffy can't fight in the form of Smoker, and it's clear that the end of the East Blue saga was when the series hit its stride.
** And then Crocodile, Nico Robin and the Alabasta arc up the ante, going from relatively minor conflicts to an all-out civil war. It also marks the point where the heroes start ending up on the verge of defeat (''repeatedly'') by an opponent far beyond their level, as well as expanding on the series' MythArc (becoming far more than Luffy searching for some buried treasure and becoming King of the Pirates.)
** Admiral Akainu finally averts the "Nobody dies outside of flashbacks" rule [[spoiler: by killing Ace.]] Blackbeard follows it up soon after by [[spoiler: killing Whitebeard and bringing about a new age of pirates.]]
** Donquixote Doflamingo. While the main villains of the previous two arcs, Hody Jones and Caesar Clown, may have been nothing short of despicable, neither of them presented any real threat to our protagonist and [[CurbStompBattle were easily taken out]]. Then came the Dressrosa arc, and you have Luffy struggling for the first time since the timeskip just to keep up with Doflamingo, and even [[spoiler:Trafalgar Law getting his right arm cut and being beaten half to death by the Shichibukai]]. Not only that, but in this arc we discover that Doflamingo [[spoiler:was once a World Noble and that those who carry the D are considered their "[[ArchEnemy natural enemies]]"]], which makes his conflict with Luffy and [[spoiler:Law]] all the more meaningful. Add to this his alliance with [[spoiler:Kaido]] and his [[spoiler:underworld persona, "Joker"]], and Doflamingo is easily, so far, the most dangerous enemy the Straw Hat pirates have come across since the timeskip (and, arguably, ''the entire series'').
** ''Manga/OnePiece'' usually has a strange SortingAlgorithmOfEvil with its BigBad bosses, ranging from dangerously competent to incompetent with each antagonist, with the occasional appearance of a serious threat like a Warlord like Kuma or Mihawk and the Three Admirals show up in which the situation drastically becomes more threatening. Then Akainu, the last of those three Admirals makes his debut and completely breaks the Status Quo by [[spoiler: killing Ace]], and the story's gotten significantly more DarkerAndEdgier in both its story and its enemies, while still retaining its positive elements.
** Any admiral introduction pre-timeskip serves as one - Aokiji's first appearance not only showed characters the power of a Marine admiral, but also serves as the beginning of the unusually dark Enies Lobby saga, and Kizaru was one of the reasons [[spoiler: the crew got separated and Luffy was forced to fight alone during the next several arcs]], which was rather unfortunate, since [[spoiler: Marinford war was one of them]].
** Introduction of [[spoiler: the Pacifistas]] served as one - the crew has to fight one of them together, using all of their strength to win, only for [[spoiler: Sentomaru to arrive with another one]]. That was the first time that Luffy gave the order to run without trying to fight back. And it was before [[spoiler: admiral Kizaru and Bartolomew Kuma arrived on the scene]].
* Much like its SpiritualSuccessor ''Claymore'', ''{{Manga/Berserk}}'' is nothing short of a DarkFantasy series. However, the TV series is considerably LighterAndSofter than its manga counterpart, so for the majority of the [[PragmaticAdaptation TV series']] run, it was basically composed of Guts and Griffith talking about dreams and ambition, the Hawks battling the Tudor Empire for the Kingdom of Midland and a bunch of political stuff, and developing characterization that wasn't derailed by {{Adaptation Induced Plothole}}s or AdaptationExplanationExtrication. But when Nosferatu Zodd was introduced with his prophecy halfway through the series, followed by the introduction of the [[BigBadDuumvirate Godhand]] toward the end [[spoiler: especially the transformation of Griffith]], we knew that this series was going to [[DownerEnding end on a bad note.]] Within the manga itself, the Skull Knight, despite not being a villain, manages to be this since whenever he shows it, tends to mean things will get bad.

* ''Manga/TsubasaReservoirChronicle'' has a rather interesting example where this trope is actually a ''heroic'' character, (or at least a good guy). Confused? [[spoiler: Halfway through the manga, it's revealed that the main character Syaoran is actually a clone of another "Syaoran" that The BigBad had locked away. The Original "Syaoran" eventually manages to escape and gets warped to where the heroes are, but by that time, Clone Syaoran (known as "Cloney" by the fans) has reverted to a heartless automaton. Cloney becomes an antagonist while "Syaoran" becomes the new main character]], and from then on, the manga is a hell of a lot darker than it was before.
* ''Anime/SonicX'':
** The Metarex in the second series (third season outside of Japan) fit this trope really well. So basically, the first two seasons of the show were pretty much light-hearted and funny in tone. Then cue the arrival of the Metarex, a group of dangerous robots [[spoiler: led by cyborg male Seedrians/Cosmo's race]] that plan to harness the power of the Planet Eggs to [[spoiler:exterminate all animal life in the galaxy so plants can rule]]. The Metarex come in many different types of their own, like the one-shot villain Red Pine, the LaughablyEvil [[TheBrute brute]] Yellow Zelkova, emotionless monsters like Pale Bay Leaf as well as Black Narcissus, who [[MoralEventHorizon captured and tortured Chris and Cosmo and used them as bait to lure Sonic to him]], and [[TragicVillain the tragically villainous]] MagnificentBastard Dark Oak himself.
** Even before that, we had Chaos, who was this just like in the games. An EldritchAbomination whose appearance becomes more monstrous as he "evolves" and gets more powerful. Unlike Eggman, he has no humorous traits, and his debut episode marked the series' shift toward more serious, continuity-heavy storytelling, contrasting previous episodes' lighthearted adventures and MonsterOfTheWeek format. With such dramatic tone shift, it's no wonder 4Kids opted to mark his debut episode as the premiere of the second season outside of Japan.
** And even before Chaos, we have the E-99 Eggsterminator, which, after transforming from the Egg Fort II and becoming empowered by the six Chaos Emeralds, becomes one of the few villains which brings about a very high possibility of Sonic dying as it soon goes insane and [[NoHoldsBarredBeatdown starts beating poor Sonic to death]], which [[EvenEvilHasStandards unnerves even Eggman]] and horrifies Chris into crying for the beatdown to stop.
* ''Manga/FairyTail'' has several.
** Jellal is the first villain who poses a serious threat to the cast's lives, and is trying to return [[UltimateEvil Zeref]] himself, as opposed to the various demon's Zeref created that have been sought out in earlier arcs, or power skirmishes that have otherwise been the focus. In addition, while previous tragic backstories have been about losing or fighting with family members, his and Erza's past is full of all kinds of slavery, torture, and betrayal. After Jellal, every arc is some serious threat that will either kill the cast or destroy the country.
** The second is Hades, who is also the second villain to seek Zeref. He turns the first lighthearted arc in over 100 chapters into a fight for survival that ends with many characters' sufferings turn out to have been for no reason, Zeref potentially unleashed on the world, Fairy Tail's past being revealed to have quite a bit of darkness attached to it, and he [[spoiler:inadvertently summons an evil dragon that leaves the core cast LegallyDead for seven years]].
** The dark guild [[OurDemonsAreDifferent Tartaros]] as a whole become this over the timeskip, as they make their introduction by killing most of the Magic Council in a scene ''very'' reminiscent of a terrorist bombing, and their arc includes several attempted assassinations on the former Council members, DeadlyGas attacks that kill hundreds of innocent civilians, and ColdBloodedTorture.
** Zeref himself invokes this trope after the timeskip, where he plans to ''wipe out humanity'', [[spoiler:and the previously mentioned evil dragon Acnologia ups the ante by not only almost killing the entire main cast, he also murders Natsu's dragon dad Igneel in front of him.]]

* In ''Anime/StreetFighterIIV'', Vega's introduction and battle with Ken marks a tonal shift in the show, which was comparatively lighthearted and episodic up to that point. Vega's battle with Ken is one of the most brutal in the series, if not the entire franchise, and his defeat marks the first appearance of BigBad M. Bison. The show quickly becomes even darker from that point on, also developing a MythArc that lasts until the finale.
* ''Manga/{{Toriko}}'' was a light hearted food hunting series with the occasional creepy GT Robots, and the arc after them is another finding secret recipe mission much like prior to their appearances. [[GutPunch Then Tommyrod shows up]]. Unlike Starjun and Grinpatch, who were NobleDemon and AffablyEvil villains respectively, Tommyrod kept [[BodyHorror all kinds of hideous parasitic insects within his body]], who seriously tries to kill Toriko [[spoiler: and actually manages to win the fight, despite getting an awesome asskicking]], and from there the story gets much darker.
* ''Anime/TengenToppaGurrenLagann'' has Thymilph, who [[spoiler: [[HeroKiller manages to kill Kamina]]]], though he ended up ''tame'' compared to Lordgenome and [[spoiler: the Anti-Spirals]].
* By the time [[spoiler:Deep Blue finally steps out of the shadows]] in ''Manga/TokyoMewMew'', things start taking a turn for the darker and more dramatic for the Mew Mews.
* Vicious from ''Anime/CowboyBebop''. Not only is he the main antagonist of the five episodes he's in, he's also a major threat to Spike and he brings the foremost conflict of the series in with him. [[PluckyComicRelief Edward]] [[ShooOutTheClowns seems to be largely absent from his episodes]].
** Julia is a non-villainous example, but her reappearance kicks off the final plot arc. [[spoiler: And her death foreshadows its conclusion.]]
* ''Manga/CityHunter'' is a strange version. It started serious (albeith with some dose of silliness), then got comedic in the Sayaka Ryujin arc and stayed comedic for most of its run, only for Sonia Field [[spoiler: who wants to kill Ryo because he ''killed her father'', who also was his partner at the time]] to bring back the seriousness. There had been other serious story arcs (chiefly Rosemary Moon's), and it happens that [[spoiler: Sonia's father forced Ryo to kill him to protect her]], but this time the story remained serious as it was before Sayaka Ryujin, culminating in the major antagonist of the initial part of the manga returning to settle the score.
* ''Anime/TenchiMuyoGXP'' has [[SpacePirate Tarant Shunk]], a man so ruthless that even other pirates fear him. The episode that introduces him is the first and only one in the entire series to show any violent bloodshed.
* While the original ''Anime/QueensBlade'' series (both the anime and the original gamebook continuity) didn't have any of them (except [[spoiler:Aldra in the Rurou no Senshi manga]]), in the ''QB Rebellion sequel'' we have ''three'' of them for continuity: [[spoiler:Captain Liliana and Ymir in the anime, as Liliana stole Vingt from Huit, and later Ymir uses dark powers for controlling the undead, and Sigui in the gamebook continuity, as she's the one of the few people that gives Annelotte, the main heroine from ''Rebellion'', a real challenge]].
* ''Manga/KamisamaKiss'' is mostly a RomanticComedy but when Akura-Ou shows up things get darker and people start dying violent, bloody deaths and in large numbers.
* ''Manga/BoboboboBobobo'' is a WidgetSeries filled with {{Shonen}} tropes and SurrealHumor, then Czar Baldy-Bald the III, and this misanthropic megalomaniac causes the series to get much more violent, especially by Shinsetsu where he achieves his BigBad status again to make the empire worse than it was before.
* While the series maintains an episodic MonsterOfTheWeek format even after her appearance, the addition of [[spoiler:Northa]] to the cast of ''Anime/FreshPrettyCure'' marked the arrival of a far stronger villain who was also dead serious about her intentions. [[spoiler:Even the monsters of the week got stronger (thanks to her new sorewatase seeds).]] After [[spoiler:Northa]] came the Dark Precure of ''Anime/HeartcatchPrettyCure'', a villain who makes her mark by defeating the veteran Cure Moonlight in her first appearance. Every other appearance pushes Cures Blossom, Marine and SixthRanger Sunshine into corners until Moonlight gets back into the saddle.
* ''Anime/HappinessChargePrettyCure's'' Phantom, the "Pretty Cure Hunter" is this. Unlike [[spoiler:Northa]] or the Dark Precure, Phantom actually ''defeats'' Pretty Cure, depowering them, trapping them in crystal mirrors and shoving them in what appears to be a ''graveyard''.
* The ''Manga/SailorMoon'' manga's first arc Queen Beryl as this role, when she started to actually act, it meant Usagi' love interest was [[BrainwashedAndCrazy brainwashed]] and [[EldritchAbomination Queen Metalia is revived]]. The ''[[Anime/SailorMoon anime]]'' biggest case was Queen Nehelenia and Sailor Galaxia. Both arcs, when she's starting acting mark an end to the series comedic moments, and lots of characters dying.
** [[ApocalypseMaiden Sailor Saturn]] is this for the hero's side. Given [[ApocalypseHow what her]] [[ResetButton job is]], even the smallest inkling of her [[SealedGoodInACan possibly awakening]] will make any moment deathly serious. Usually for good reason considering [[GodzillaThreshold how severe things have to be for her to awaken in the first place.]]
* Sensui from ''Manga/YuYuHakusho'' who killed the main character of the damn series and succeeded in opening the tunnel to demon world, which potentially could have wiped out human life. He's also a manipulative corrupter, ruthlessly sacrificing children as pawns and introduced really dark nihilistic themes into the series.
* ''Manga/AnimalLand'' starts off with Tarouza, a human child, dealing with relatively simple challenges from trying to get the various animals to get along in harmony, to defending against gigantic carnivores. Then comes Jyu, another human child who is a SocialDarwinist, who sees all that Tarouza is trying to do be an upfront against nature and thus burns down all of the hard work Tarouza did in seven years. Jyu is then upstaged in more ways than one by Giller. He is a mysterious MadScientist type character who causes all sorts of harm towards the animals in the world. Also he uses {{Animalistic Abomination}}s known as Chimeras.
* In ''Anime/KillLaKill'':
** Things quickly got darker and darker from the moment [[CuteAndPsycho Nui Harime]] showed up in episode 11, especially since that she's the one [[spoiler: [[YouKilledMyFather who killed Ryuko's father]]]].
** After [[spoiler: Satsuki's betrayal and attempted decapitation failed]], Ragyo Kiryuin showed just what a living nightmare she was. For all her campiness, her villainy is played brutally straight, shown when she [[spoiler: thrashes Satsuki and imprisons her, and then brainwashes Ryuko and sews Junketsu ''into her skin'' before sending her to kill Nudist Beach, and then putting into action a plan to ''blow up Earth'']].
* ''Anime/TenchiMuyo'' is typically a lighthearted harem comedy, in both the original OVA and in ''Anime/TenchiUniverse''. The exceptions in both occur when Kagato shows up. While more powerful villains than him appeared in the OVA, they never had as much of an impact as him.
** The movie ''Tenchi In Love'' is mostly like the rest of the lighthearted "Universe" series with barely a mentioned of the heavily built up EldritchAbomination Kain brought up at the start of the movie. But then towards the end of the film, Kain shows up, and unlike villains in the franchise before him, he actually kills somebody, in an outright horrific manner to boot.
** ''Anime/TenchiInTokyo'' is probably the lightest and most comical series in the Tenchi Universe. However, when [[BigBad Yugi]] shows up, the show starts to get much darker as she tries to split up Tenchi from the girls and dark plot twists start appearing in the show.
* While ''Anime/PantyAndStockingWithGarterbelt'' never loses its humor, the plot takes a turn for the darker once CoDragons [[EvilCounterpart Scanty and Kneesocks]] debut. Though they quickly fall into VillainDecay, some of their plans can be pretty damn [[FridgeHorror scary when you think about it]]. Then there's their [[BigBad master]], [[spoiler:Corset]], who's far more competent than his minions, [[BadBoss who he frequently tortures]] [[YouHaveFailedMe for their failures]] (by the way, they're [[AbusiveParents his daughters]]). His plan? Create HellOnEarth.
* ''Manga/AkameGaKill'':
** The series had a strong mixture of comedy and heartwarming moments in addition to some tearjerkers where numerous likable characters were killed off. Then the manga introduces [[OverlordJr Syura]], [[BigBad Prime Minister Honest]]'s [[TheHedonist hedonistic, self-absorbed son]]. Worse yet, he brings with him his [[MadScientist own]] [[BloodKnight gang]] [[EvilDiva of]] [[SerialRapist repulsive]] [[MonsterClown lackeys]]. They become the Wild Hunt, a secret police organization [[EvilerThanThou who happen to be way worse]] than [[AntiVillain the Jaegers]].
** Before Syura and his thugs were even introduced, there was Seryu Ubiquitous, self-proclaimed "Officer of Justice" and [[AxCrazy a very unhinged young lady]]. While she is just an AntiVillain like the rest of the Jaegers, her fight against Sheele and Mine was the first reminder that Night Raid [[NotSoInvincibleAfterAll isn't completely invincible after all]] and that [[AnyoneCanDie even the good guys can die.]]
* ''Manga/InuYasha'' started out with the MonsterOfTheWeek formula with Inuyasha and Kagome spending each episode confronting various demons in order to retrieve the Shikon Jewels. However, when [[BigBad Naraku]] made his appearance, the series started revolving around the team's efforts to defeat Naraku while also exploring the MythArc of Naraku and how he tortured each character in the past, such as [[spoiler: being the one who nearly destroys Inuyasha and Kikyo's relationship with each other]].
* Once Aion appears in the anime of ''Manga/ChronoCrusade'' the series grows incredibly dark as the first several episodes are fairly light-hearted. His first appearance marks the first major tonal shift.
* Whenever the Master of Synapse appears in ''Manga/HeavensLostProperty'' you can be sure the series will turn darker.

* ''Manga/AssassinationClassroom'':
** When [[DrillSergeantNasty Akira Takaoka]] shows his true nature, the story shifts from a fun, uplifting comedy into the darker, more serious themes of assassination. [[spoiler: [[HijackedByGanon This goes double for his involvement during Class 3-E's island vacation.]]]]
** The God of Death. Secondary characters get killed off once he appears, [[spoiler: though they get better, ]] and he comes ''very'' close to killing Class E.
** Akari Yukimura, [[spoiler: AKA the true identity of Kaede Kayano]]. Her first appearance alone makes everyone, in-universe and out, rethink everything they knew about [[spoiler: Kayano]]. And from there, it leads directly to some ''very'' major reveals about [[spoiler: Koro-sensei's past.]]
* Whenever [[PsychoForHire Gauron]]'s around in ''LightNovel/FullMetalPanic'', the joking ''stops''.
* In ''Manga/JoJosBizarreAdventure'', while the series usually shifts between jovial action with elements of horror mixed in, the presence of any of the main villains (Dio, Kars, [[spoiler: Kira, Diavolo, Pucci and Funny Valentine]]) immediately ratchets up the tension, considering most of them [[spoiler: manage to [[AnyoneCanDie kill several members of the Jojo's team]]]].
** ''[[Manga/JoJosBizarreAdventureStardustCrusaders Stardust Crusaders]]'' is a notable case. In the first half of the series the assassins sent by DIO start range from mildly effective to completely and somewhat comically ineffectual. That all goes out the window the moment Pet Shop shows up. From that point onwards the remaining villains get progressively more deranged and dangerous.
*** Vanilla Ice is a perfect example of this. The man makes his introduction by killing off [[spoiler:Avdol]] (for real this time), and proceeding to [[spoiler:kill the team's mascot, the loveable stand-wielding dog Iggy]], by literally ''[[KickTheDog kicking him to death]]''. Suffice it to say, transitioning from light hearted villains to [[HeroKiller hero killing]] maniacs makes for quite the jarring viewing experience.
** Diavolo manages to stand out even among the other candidates due ''[[Manga/JoJosBizarreAdventureVentoAureo Vento Aureo]]'' ''already'' arguably being the darkest entry yet due to this story showcasing a lot more intense bruality in its fights, the death count being higher than ever before, and the moral ambiguousness of every character involved, ''especially'' its protagonists. However, ALL of that gets permanently turned UpToEleven the minute Diavolo gets fully involved in the story, with his [[KinslayingIsASpecialKindOfEvil true intentions being revealed]] and how his Stand, [[TimeMaster King Crimson]] comes as less of a typical FightingSpirit the readers come to expect in ''Jojo'', and more of an pure murder machine when it attacks.
* The plot for ''Manga/{{Gangsta}}'' finally arrives when [[KnifeNut Doug]] shows up.
* ''Manga/FruitsBasket'':
** The series started out pretty lighthearted with Tohru having comedic adventures with the Sohma family. All that changes when the abusive family head, Akito Sohma, appears, and the manga started focusing more on the tragic side effects that the Sohma Family's curse had on its members.
* The ''Manga/GunsmithCats'' manga starts lightly, until Gray shows up [[spoiler: and almost kills Rally]] by the time his arc ends. The villains afterwards get worse, ending with the infamous Goldie.
* ''Anime/ValkyrieDriveMermaid'' takes a more darker tone with the introduction of Momoka and her two unnamed partners. [[spoiler: Momoka's defeated Akira, who was largely responsible for keeping the peace on the island and helps Charlotte become governor. Charlotte, being more of a tyrant tries to forcible round up all the girls not in Feste.]]
* ''Manga/BlackCat'' is normally about Train and his friends going on adventures to capture criminals as sweepers, but whenever [[BigBad Creed]] is introduced, things get dark really fast for Train and his friends.
* ''Anime/SamuraiFlamenco'' begins as a lighthearted comedy series about male model Masayoshi Hazama who has aspirations of becoming a HenshinHero. The first quarter of the show is mostly his exploits fighting petty crime using [[ImprobableWeaponUser office]][[MakesSenseInContext supplies]]. He even gets enlisted by the police department as a special liason for solving crime! Then episode 7 hits with [[spoiler: Guillotine Gorilla. After helping the police raid what seemed to be a standard drug warehouse, Hazama witnesses a cornered worker takes a pill and transforms into a giant gorilla with a guillotine for a torso, grabbing a nearby police officer and quickly decapitating him.]] From then on, the show becomes a full-fledged action show, that still retains some of its lighthearted humor while retaining some dark villains.
* ''Manga/SchoolLive'' seems like a normal {{Iyashikei}} series with cute school girl antics and comedy, but then the end of the first chapter/episode reveals that a zombie apocalypse has been going on the whole time. The zombies themselves qualify not just due to making the series darker, but also because they're played very seriously, with no comedy being in any scene that has them in it.
** [[spoiler: The zombified Megumi]] in particular is a special example, as [[spoiler: not only is it both sad and disturbing seeing the group's BigGood and original TeamMom now rendered a frightening shell of her former self, but she also bites Kurumi (who couldn't bring herself to kill the zombified version of someone she knew and loved dearly) and very nearly kills her as a result. In fact, she still haunts the girls because Kurumi appears to still be infected and in the stages of becoming a zombie]]. The anime takes this up even further by [[spoiler: Having the girls' DarkestHour begin right when Kurumi is infected, due to the zombies breaking into the school only minutes after this happens]].
** The later chapters have introduced The Melee Fight Crew, the first human antagonists in the manga. They're ruthless, hostile and overly paranoid survivors who will viciously kill anyone they suspect to be a threat without remorse, and Chapter 47 reveals that [[spoiler: they've even killed several of their own members in order to preserve all the food for themselves]]. The chapters with heavy focus on them feature absolutly no comedy at all and further highlight how dark the series truely is. This is further examplified with the group's leaders: The currently unnamed Blond Man is remorseless about [[spoiler: leaving several of his own allies to die]] as well as the aforementioned murders the group has committed, while also viewing other survivors only as tools to be used, while Ayaka is utterly psychotic and actually enjoys the Zombie Apocaylpse and all the deaths and suffering it has caused.
* Julian Ainsworth serves as this for ''Manga/FateKaleidLinerPrismaIllya'' as the antagonist who sets the stage for the much [[DarkerAndEdgier grimmer and darker]] 3rei, where Miyu is captured and the protagonists transported to his CrapsackWorld. In addition to him and his cronies being played more seriously and capable of greater brutality than previous antagonists, his machinations means the SliceOfLife aspects of the series are largely removed, leading to comparisons of the previously lighthearted doujin to other, more typically dark Type-Moon material.
* ''LightNovel/ReZero'' Seems like a typical "Trapped in a fantasy world" with a NEET otaku protagonist. By the end of the first episode, he finds himself being able to come back from the death towards a certain checkpoint. The first major antagonist, Elsa Grienhert, manages to set the tone for the series as a whole, but in arc 3, its the witch cult from Rem and Ram's past as shown originally in Arc 2 where they make their debut, and turn a relatively darker then normal Light Novel series and turn into one of the Darkest Fantasy anime since ''Berserk'', especially with the First Archbishop introduced, Betelgeuce Romanee-Canti, who [[spoiler: in the original Web Novel, killed and mangled Rem's dead body in mutiple increasingly twisted ways, eventually casuing Subaru to snap.]] This is made all of the more disturbing when [[WordOfGod the author, Tappei Nagatsuki]] states that of all the archbishops, Betelgeuce is the '''nicest''' one fo them.
* ''LightNovel/TheSacredBlacksmith'' is a lighthearted, troperiffic, and a little fanservicey EpicFantasy manga/anime/light novel, at least until Siegfried, the main antagonist, shows up. He is played seriously, and his actions darkens the story UpToEleven, especially in the manga and light novel. By far his most henious action is [[spoiler: brutally beating up, mocking and humilliating the female lead in an action that is, essentially, both physical and psychological rape, but without actual penetration]]. The aforementioned scene, which would not be out of place in ''Manga/{{Berserk}}'', comes out as a big shock because it is the last thing you think may happen in such a comedic fantasy series.
* ''Anime/LittleWitchAcademia2017'':
** [[BigBad Croix]] has a massive LackOfEmpathy of anything that isn't [[ItsAllAboutMe herself]]. The work starts off pretty cheery but the show turns into a minor case of a Melodrama. She attempts to murder Akko multiple times and her companions out of spite and even attempts to start a major war just for her goal while lying to be a WellIntentionedExtremist as well as being the cause of Akko losing her magic. She then has a HeelFaceTurn after her plan fails and when the show seems to be light and happy again...
** [[EldritchAbomination The Noir Rod]] appears. It's an OmnicidalManiac that has various attempts of BodyHorror in it's appearances and is the cause of most NightmareFuel throughout the story. It also darkens most of Episode 25 except the ending by turning into a giant nuke.
* Despite its episodic tone, ''Anime/YokaiWatch'' has some examples if a particular plot is to be renditioned in the games:
** [[TheHeavy Kin and Gin]] in the first (Japanese) season. Whenever these EvilOldFolks show, you can safely bet the plot of that episode is serious, as [[spoiler: both send Jibanyan and then Whisper back in time to a moment (or era, in the case of the latter) where something crucial to their lives and those dear to them happens, and try to make some changes under the guise of saving their lives, but ultimately try to avert their fateful meetings with Nate]]. Also, they fulfill this role in the first movie where [[spoiler: successfully break Nathaniel's friendship spirit in order to negate the need for create the Yo-kai Watch, as well as being NotSoHarmless during the battle in the climax]]. All of that [[spoiler: under the orders of [[BigBad Dame Dedtime]], whose backstory is all but pleasant]].
** Aristokat and Duke Doggy from the second (Japanese) season also count, as in the episode they appear in (which lays several plot threads to the second movie) they instigate the plot [[spoiler: to impede the upgrade to the Yo-kai Watch U, and their apperance foreshadows the debut of [[MysanthropeSupreme Zazel]], who tried to imprison and dethrone Lord Enma and abitrarily ordered the Yo-kai to return to the Yo-kai World in said movie]].
* The SequelSeries ''Anime/YokaiWatchShadowside'' has several examples who manage to outdo those from the original series pretty easily, given and befitting the DarkerAndEdgier tone of the series:
** The pilot movie ''Anime/YokaiWatchShadowsideTheReturnOfTheOniKing'' has its BigBad, the titular Oni King: Rasen. Easily the vilest and cruelest villain in the entire franchise, as him being the true leader of the Onimaro, he feeds on the malice of humans accumulated by them to become more powerful, simply for his own amusement. He's also no pushover, [[spoiler:as he easily brushed several attacks of the heroes' Yo-kai friends and even ''Enma and Zazel'', and it took the combined efforts of [[FusionDance Yami Enma]], several element-vielding Yo-kai, and Touma with the Fudou Raimeiken to destroy him, and he became ''dangerously close to killing two main characters'', as heavily wounding Natsume and throwing her to a river to drown to death -only to be timely saved by Azure Dragon- and cheap-shotting Touma with a blood dart upon being decapitated before finally being put down for good, effectivelly killing Touma; the boy would have stayed dead if not for [[MookFaceTurn the three Onimaro]] who he truly befriended pulling an HeroicSacrifice to get him better]].
** The series has Haruya Sakami/[[spoiler:Shutendoji]] and his two underlings, Fukurou and Douketsu. His goal of obtaining the Youseiken (one of which being the Fudou Raimeiken held by Touma) and finding "the Princess" in order to take over the Youmakai leads him to order Fukurou to try to locate her by blowing darts coated with a malice-enhancing toxin at humans, thus turning them in some form of Wicked, as well as forcing some Yo-kai to their Shadowside forms; having his Dragon Douketsu stall the heroes (which Douketsu does rather efficiently -cementing himself as an example of this trope-, as the heroes never truly score a victory over him, [[spoiler:and in one ocassion he even puts Suzaku, one of Akinori's strongest Yo-kai, close to death]]), and using a human fortune-teller (which he later [[YouHaveOutlivedYourUsefulness nonchalantly depowers]]) [[spoiler:to lure Touma to a trap in order to seize the Fudou Raimeiken and ordering Fukurou to dispose of him, which he luckily fails.]] Fukurou himself has proven to be this when, [[spoiler:Haruya [[YouHaveOutlivedYourUsefulness coldly deeming him useless]] causes him to lose it and try to prove his worth by using the Fudou Raimeiken to turn into a [[EvilCounterpart dark version of Fudou Myouou]] and truly giving the heroes a run for their money, and with Soranaki's influence, he gets an OneWingedAngel form which proves to be quite powerful for even Douketsu -which as a fighter and Haruya's Dragon, that's saying enough- and it takes Touma attaining a SuperMode for Fudou Myouou to put him down for good]]. All of the above comes to a head when [[spoiler: Shutendoji has Keisuke kidnapped in order to ramsom the Youseiken, and when Natsume and co. naturally come to rescue him, he and Douketsu [[CurbStompBattle ''easily'' steamroll]] several of the Yo-kai they summon, like Jibanyan, Komasan, Micchy, Junior, Azure Dragon, Blazion, and Blizzaria; and it took the Soranaki suddenly appearing and prompting Natsume briefly awakening as the Princess, Shuka, in order to subdue it, ironically putting Shutendoji several steps closer to his goal.]]
** [[spoiler:Jorogumo]] easily qualifies, as [[spoiler:she made the first KnightOfCerebus do her bidding, making him look like a LaughablyEvil villain and thus playing him as a fool by taking advantage of his quest for the Princess, -and only Douketsu knew she was toying with him and tried to tell him, to no avail-.]] [[spoiler:She used Ayame Himeno as her vessel, all while the poor girl barely suspected anything, and blended with the detective agency all while none of them didn't even suspect anything (especially Akinori, who had a crush on Ayame at first sight), killed a MonsterOfTheWeek who just underwent a HeelFaceTurn and ordered Haruya to do the same with another one.]] [[spoiler:When she reveals herself thanks to Haruya, she puts him and Douketsu out of commision rather easily and mops the floor with Jibanyan and ''Fudou Myouou Ten'' forcing the heroes to retreat.]]
** The aforementioned [[spoiler:Soranaki]] is shaping to be an example of this trope, if ''[[Anime/YokaiWatchForeverFriends Forever Friends]]'' is an indication. He is [[spoiler:an AncientEvil which nearly drove the Yo-kai race to extinction, and he coincidently awakens in the setting of the film (the 1960's), transforming Shien into Maou Shien, prompting Lord Enma and Susanoo, Tsukuyomi, and Amaterasu to move out to stop him]]. He [[spoiler:resurfaces after 90 years, spreading [[TheCorruption a Virus which makes Yo-kai hostile by tapping on the wickedness on their heart]] [[PowerBornOfMadness and converting it into power in their Shadowside forms]]. [[spoiler:He was the one who turned Fukurou into Shinmagunjin Fukurou, forced Shuka to awaken within Natsume, and corrupted Douketsu, forcing Shutendoji to kill him]]. He eventually became so powerful [[spoiler:that he infected several of the heroes' Yo-kai friends and ''Kaira'' in a full-scale assault]], and [[spoiler:the Youseiken which were supposed to awake Shuka? They were instead the key to awake ''him'' instead!]] [[spoiler:It took Natsume and her friends fully awakening into Shuka and her retainers, the efforts of several Yo-kai, and a new Fudou Myouou, to defeat him for good.]]

** [[HeroKiller Stain]] - Not only is he ''literally'' the first villain that Midoriya and Co. face in the "real world" outside the safety net of school, he is also the blood-stained wake-up call that forces the young heroes to confront the grey realities of hate, justice, and vengeance that simply cannot be quantified and defined by classical notions of "black and white" morality.
** [[GreaterScopeVillain All For One]] - The mastermind behind the League of Villains, mentoring the leader of said group, and he is the personal enemy of All Might. When he finally steps in to fight, he takes out several heroes in mere seconds. His actions continue to haunt the heroes of the world even in the present day. While Stain made the story much darker upon his entrance, All for One's arrival is the point where the series really goes from a somewhat light-hearted (but not without danger) AcademyOfAdventure series to constant life-or-death situations against people hell-bent on destroying society as we know it.
** [[{{Yakuza}} Overhaul]] - [[spoiler:He is the first villain to actually murder major characters in the series upfront, both Magne and Nighteye, a villain and a hero. He also nearly killed several others, and introduced the prospect of Character Deaths to the story and how sometimes a hero can pay the ultimate sacrifice.]]
** [[WakeUpCallBoss High End]] - Before High-End showed up, Nomus were generally expected to be mindless muscle, and the good guys learned to beat them. [[spoiler:Then ''this'' one brutally injures the new number one pro hero and rips apart a whole side of his face and an eye.]]
* Although it is always DarkerAndEdgier than your typical MagicalGirl show, ''Anime/TweenyWitches'' starts out as kind of cheerful with Arusu having enchanting adventures with her friends and the local {{Cute Witch}}es. Then the series gets much more serious after Sigma makes his debut, leading the plot to become Arusu and her friends struggling in the war between the witches and the warlocks and TheEndOfTheWorldAsWeKnowIt.

* In ''Anime/FistOfTheNorthStar'', most of the villains who faced Kenshiro had no success in doing any lasting damage. They would, if they were lucky, kill a supporting character who had no skill in fighting or a background character, but that was usually it before Kenshiro killed them. Then along came the mighty [[LargeAndInCharge Raoh]], who had been hinted at a few times before appearing. In his first encounter, he fatally injured Rei, nearly killed Toki, and fought Kenshiro to a draw, cementing his position as the BigBad and a villain to be respected.
* ''Manga/BlackClover'':
** Mars is the first opponent in the series to come extremely close to killing Asta and his allies.
** The Dark Triad's introduction as the new main villains change the story to a much darker tone. Even when the heroes try to fight back, their sheer sadism, cruelty and misanthropic world views make the battles much more grisly.
* ''Manga/FruitsBasket'' begins as an adorable, lighthearted series that follows a cute high school girl who befriends a lot of pretty boys who transform into adorable animals... until [[BigBad Akito Sohma]] makes his [[spoiler:(actually [[RaisedAsTheOppositeGender her]])]] debut and it's revealed that he's abused numerous members of the Sohma family in various horrific ways, both physical and mental. In direct contrast to [[{{Tsundere}} Kagura's]] [[DoubleStandardAbuseFemaleOnMale abuse of Kyo]], '''''nothing''''' Akito does to the Zodiac members, as well as any "outsiders" who butt in, is PlayedForLaughs in the slightest, and every time he's on-screen, the comedy and humor virtually disappear.

** As soon as the psychotic [[TheAce Minerva Liddell]] appears in the manga, the humour level drops, the becomes story dark and horrifying. Once she made her appearance, the story was no longer an ecchi comedy, but one of horror and brutality where teenage girls are tortured.

** Rei Katsura from ''Anime/DigimonUniverseApplimonsters''. He is an AntiHero, and whenever he's around, there's literally nothing ''funny'' about this guy.

* ''Manga/RosarioToVampire'' MonsterOfTheWeek formula progressively stopped being the ''main'' formula due to these three:

** [[EvilCounterpart Goku Black]] is the first such example for ''Anime/DragonBallSuper''. While Frieza was the first technically malevolent antagonist of the series, his arc was lighthearted and threat diminished by Whis and Beerus' presence. Goku Black is played more seriously- his first act bringing Future Trunks' Earth to the brink of extinction and setting up a darker tone for the series.

** And even before Chaos, we have the E-99 Eggsterminator, which, after transforming from the Egg Fort II and becoming empowered by the six Chaos Emeralds, becomes one of the few villains which brings about a very high possibility of Sonic dying as it soon goes insane and starts beating poor Sonic to death, which unnerves even Eggman and horrifies Chris into crying for the beatdown to stop.

** [[{{Yakuza}} Overhaul]] - [[spoiler:He is the first villain to actually murder major characters in the series upfront, both Magne and Nighteye, a villain and a hero. He also nearly killed several others, and introduced the prospect of CharacterDeath to the story and how sometimes a hero can pay the ultimate sacrifice.]]

** General Rilldo in ''Anime/DragonBallGT''; until he showed up, ''GT'' was a throwback to the comedy of early DB.

** Currently quoted in the main page. Kurumi Tokisaki is merely a peek of what the true darkness is in this story. Once [[BigBad Sir Isaac Ray Peram Westcott]] 6[[spoiler:starts meddling with the protagonists, the story becomes more than just a race to seal the most Spirits and also bringing the story to a darker path.]] This takes two stages. When he and his minions start take actions against the protagonists, he reveals various plot threads that has been foreshadowed since the beginning (Phantom's involvement with the Sephira Crystal) as well as new ones (Inverse Spirits), and things get serious. And then, numerous +18 incidents happens when he is around; from torture of teenage girls, rape of Spirits and mutilations scenes. The story that was suppose to light-hearted with numerous jokes and funny moments becomes a living hell. This continues up until Volume 13, when [[spoiler:he finally gains one of the Spirit's Qliphoth Crystals, and becomes an Inverse Spirit himself]], where he ups the ante by taking actions himself. Not only things get FromBadToWorse pretty fast, he even shows us in Volume 16 how ''easily'' [[spoiler:he can end the plot by simply killing Shido in the middle of his everyday life]]. Volume 19 takes it to the cake [[spoiler:when he stole Mio's powers in order to become the Second Spirit of Origin]], giving the power to control the death and existence of all creation. Until the end, every appearance of Westcott was played 100% seriously and left his mark as the most heinous villain in Light Novels' history.

** The series had a strong mixture of comedy and heartwarming moments in addition to some tearjerkers where numerous likable characters were killed off. Then the manga introduces [[OverlordJunior Syura]], [[BigBad Prime Minister Honest]]'s hedonistic, self-absorbed son. Worse yet, he brings with him his [[MadScientist own]] [[BloodKnight gang]] [[EvilDiva of]] [[SerialRapist repulsive]] [[MonsterClown lackeys]]. They become the Wild Hunt, a secret police organization [[EvilerThanThou who happen to be way worse]] than [[AntiVillain the Jaegers]].

** In the Android arc, the first two villains -- Androids [[MonsterClown 19]] and [[MadScientist 20]] -- were highly [[HarmlessVillain ineffectual]] and 19 was only able to get the jump on Goku thanks to a heart virus. Then the second group of villains -- Androids [[NatureLover 16]], [[ArrogantKungFuGuy 17]] and [[VillainessesWantHeroes 18]] -- while programmed to explicitly kill Goku, they really don't care and spend most of their arc messing around. Then ''[[UltimateLifeform Cell]]'' shows up, he almost kills Piccolo, Tenshinhan and Vegeta, succeeds in killing [[HeroKiller Goku and Trunks]] and [[NearVillainVictory almost destroys Earth]].

** General Rildo in ''Anime/DragonBallGT''; until he showed up, ''GT'' was a throwback to the comedy of early DB.

** The series had a strong mixture of comedy and heartwarming moments in addition some tearjerkers where numerous likable characters were killed off. Then the manga introduces the Wild Hunt, a secret police organization [[EvilerThanThou who happen to be way worse]] than [[AntiVillain the Jaegars]].
** There was Seryu Ubiquitous, the "Crazy Lunatic". While she is just an AntiVillain like the rest of the Jaegars, her fight against Sheele and Mine was the first reminder that Night Raid [[NotSoInvincibleAfterAll isn't completely invincible after all]] and that [[AnyoneCanDie even the good guys can die.]]

* ''Manga/ZatchBell'' tends to get a lot of these; because most of the enemies tend to be fairly goofy, it's jarring when you get someone like Zophise who's playing for keeps.