History Anime / IsekaiQuartet

** Despite Kazuma's jealously of what he thinks is the much better life Subaru leads [[spoiler: in the finale of the first season he warns Subaru against risking his life against the Destroyer, pointing out that if he dies he will stay dead.]]

* {{Hypocrite}}: While Subaru did leave out the reason his life is so hard, Kazuma of all people knows that just because someone lives in a mansion and has a party full of girls does not mean their life is all that great. What makes this especially egregious is that Kazuma has been accused of the same thing in his series.

* HypocriticalHumor:

** In [=S2E8=], while Subaru and his gang notice Viktoriya working at the butcher shop, [[FreezeFrameBonus if you look carefully]] you may notice that the customer she's serving is none other than [[spoiler:[[LightNovel/TheHeroIsOverpoweredButOverlyCautious Ristarte]], hinting at [[EarlyBirdCameo her and Seiya's appearance]] in [=S2E11=]]].

%%* EarlyBirdCameo: In Episode 8 of Season 2, when Subaru's group spots Viktoriya at the Butcher's, the customer she's serving is hidden but can clearly be seen with [[spoiler:blonde hair, white dress, blue bow, and gold bracelets: in other words, '''Ristarte''' of ''[[LightNovel/TheHeroIsOverpoweredButOverlyCautious Cautious Hero]]'', hinting at the next isekai to crossover.]]

** What seemed like just a voiceless cameo by [[spoiler:[[LightNovel/TheHeroIsOverpoweredButOverlyCautious Ristarte]]]] in episode 8 of season 2 turned out to be this for episode 11 [[spoiler:when she and Seiya visit the school festival. Or rather, Ristarte expresses the desire to, but Seiya refusing due to not knowing anything about it]].

* CrouchingMoronHiddenBadass: [[LoserDeity Aqua]]. She's an idiot, she's unlucky, but one thing she is not harmless. She demonstrated that when she attacked Ainz with Turn Undead, a low level spell that he should logically be immune to, and actually hurt him. It's implied if Kazuma hadn't dragged Aqua away that she might have killed Ainz. Rather tellingly Ainz is worried when tries to show off her more powerful Sacred Turn Undead, though she is once against stopped. Season 2 reveals that because she's a goddess, she isn't effected by Ainz' Time Stop. [[spoiler: At the end of the season, she also lands the blow that defeats the Mobile Fortress Destroyer.]]

* SlapstickKnowsNoGender: Aqua is as much of ButtMonkey as ever. Aside from her, Shaltear and Albedo are the biggest female victims.

** Tanya, surprisingly. Not only was she unaffected by Ainz's Despair Aura[[note]]Which can make the Lvl 100 Floor Guardians sweat[[/note]] and didn't even notice Demiurge's Command Mantra[[note]]Which can instantly control beings under Lvl 40 and put everyone just over that under great pressure[[/note]], but when she got angry at Aqua, she released an aura of magical power that was likened to an earthquake and noted by Ainz to have the power to exceed that of an ''8th Tier Spell'' by Yggdrasil's standards. When Ainz tried to cheat on a test using Time Stop, a '''10th Tier Spell''', she was completely immuned to that as well. And likewise when she able to block a magical dodgeball that was fuelled and had the combined properties of ''Ainz's "Nuclear Blast" and Megumin's "Explosion"'' with a magic barrier powered by Being X's Blessing, though the ball broke before she had to fully endure the attack.

** This applies to the Overlord cast as a whole. In their home series, because of the power system in the new world, they make a hobby of humillating and smashing everyone in their way with no effort, all while acting overly arrogant and racist toward anyone they meet. This crossover has them (Ainz specially) be often surprised and scared of the other characters actually matching or outclassing them in many ways. The episode 2 has Aqua of all the people almost killing Ainz and the guardians being powerless to stop it, and they keep getting shocked with the fact that they aren't invincible anymore.

* TemptingFate: Ainz dimisses Aqua's Turn Undead as harmless since it's a low level spell he should be immune to. It procedes to cause him severe pain.

** [[spoiler: [[LightNovel/TheHeroIsOverpoweredButOverlyCautious Seiya and Ristarte]] showing up]] in episode 11 of season 2.

* {{Foil}}: Each main protagonist of the four series in this crossover can be considered one to each other:
** Tanya and Ainz: Each formerly being a {{Salaryman}} - something that is usually common when it comes to the average isekai - and both are currently InvincibleVillain [[VillainProtagonist Protagonists]] in their current lives - something ''un''common in an isekai. However, Tanya, the supremely successful salaryman who was TheSociopath even in her first life, was reincarnated into an realistic world that happened to be filled with [[MilitaryMage Military Mages]] during its [[WorldWarWhatever Great War]] while Ainz, the average salaryman, was transported into an RPGMechanicsVerse full all of the typical traits in your StandardFantasySetting except ''he's'' the typical MonsterLord that now has a EmotionSuppression thanks to his undead body. Also, after being killed by a disgruntled employee he just fired, Tanya was [[GenderBender Gender Bent]] into an [[CuteAndPsycho cute, little blonde girl]] who is more often than not the IgnoredExpert to the officers she serves under. Ainz, on the other hand, was [[RaceChange transformed into an Elder Lich]] who now is the EvilOverlord and BenevolentBoss to the monsters that worship and follow his every word.
** Kazuma and Subaru: Both teenagers that are the kind of {{NEET}} you would see transported into HeroicFantasy of a stereotypical LightNovel with a [[IconicOutfit fondess for wearing tracksuits]] in the new world they are in and both have been brought BackFromTheDead multiple times in each of their own stories. However, Kazuma, who stars in a DeconstructiveParody, has been able to find his footing there well enough in the new world he's been sent to and, for all of his faults, tends to come across as TheReliableOne of his group. Meanwhile, Subaru, who serves as an DarkerAndEdgier DeconstructedCharacterArchetype, has been subjected to [[TraumaCongaLine A LOT of physical, mental, emotional, and psychological pain]] that made him actually [[MiseryBuildsCharacter grow greatly as a person]].
** Subaru and Tanya: Subaru was an unproductive and introverted {{Hikikomori}} in life before he was transported to the [[MagicalLand Kingdom of Lugnica]], failing to adapt to his situation quickly enough and got himself killed early on in the story. Tanya was an accomplished and high-ranking HR manager before her reincarnation, very quickly rising through the ranks of TheEmpire she was born-again into despite being so young. Subaru is an AllLovingHero who often displays [[HeroicSelfDeprecation self-loathing at how little he himself can accomplish]], while Tanya, [[LackOfEmpathy someone seemingly incapable of showing empathy towards the people around her]], is a {{Narcissist}} that often wants to showcase her superiority over others.
** Kazuma and Ainz: Both are the most GenreSavvy when it comes to being TrappedInAnotherWorld and both are [[BeleagueredBoss Beleaguered Bosses]] that are constantly putting a lid on the extreme antics of their respective groups, which involves putting up with the downsides of having an UnwantedHarem. However, Kazuma [[LoserProtagonist is a rather pathetic human being]] that nonetheless [[JerkWithAHeartOfGold steps up to the plate when necessary]], especially when his group's incompetency rears its ugly head more often than not, constantly doing his best to rein them in. Ainz, [[EscapistCharacter an extremely powerful lich in his setting]], on the other hand, [[SlowlySlippingIntoEvil finds himself more and more falling in line with his subordinates' line of thinking]] as time goes on.
** Tanya and Kazuma: The two died in accidents involving vehicles, have to deal with a deity that annoys them (Being X and Aqua, respectively), and despite their [[BunnyEarsLawyer respective eccentricities]], both are quite effective as TheLeader to their respective groups, displaying great efficiency at maximizing [[TheStrategist the strengths of their own teams]] and [[FlawExploitation weaknesses of any foe they face]]. However, Kazuma is the very definition of BrilliantButLazy who finds himself constantly hindered by his party's insistence on being ''[[CastFullOfCrazy so damn insufferable]]'' to work with or even tolerate on a daily basis. Tanya, [[GoGetterGirl who goes out of her way to make sure she's irreplaceable]], [[BerserkButton does NOT tolerate insubordination at all]]; [[SergeantRock having put the fear of god in the battalion she precedes over, resulting in her subordinates being as devoted to her as they are scared of her.]] Also, while both have left an negative impression with the gods mentioned before, the god that Tanya met has become more negative and antagonistic towards her, while the god Kazuma met softens up to him quite a bit.
** Ainz and Subaru: Ainz is an evolved undead [[{{Necromancer}} who greatly excels in using death magic]], while Subaru is just an average human being whose most notable magical ability is coming BackFromTheDead. Ainz, [[InvincibleVillain who is arguably the most powerful person in his world]], more often than not [[FeigningIntelligence Feigns Intelligence]] and ultimately ends up being the SpannerInTheWorks to the plans crafted around him [[AchievementsInIgnorance without even knowing it]] due to being so overpowered compared to everyone else. [[NonActionGuy As the weakest guy around in his setting]], Subaru approaches and overcomes the obstacles before him as TheChessmaster; having been TaughtByExperience and gaining the social and emotional skills worthy of entering {{Magnificent Bastard}}hood. You can see the difference between first hand in how they respectively first reacted to Tanya in UnstoppableRage about Being X: Ainz despite being magnitudes more powerful than her is intimidated by her rage twice and only kept his cool because of his EmotionSuppression. In comparison, Subaru besides his revival powers is a regular person but was able to keep his cool when faced with Tanya who exploded in rage in Episode 9 that far surpassed the rage she showed Ainz in Episode 4.
** With the arrival of Naofumi Iwatani aka the Shield Hero, he can also be stated and treated as being a foil to the titular quartet:
*** Ainz: Satoru Suzuki (Ainz's pre-Isekai identity) was an avid MMORPG player, while Naofumi was a casual gamer who preferred light novels. Ainz begins in his world as one of the most powerful beings there, while Naofumi begins as even weaker than he was in real life. However, while Ainz remains at his power level for most of the story, Naofumi grows at a quick pace through his own efforts. Ainz is always surrounded by loyal minions who obey his wishes, while Naofumi begins alone, having been betrayed by the first person he put his trust in and then the first person to truly help him without any ulterior motives is a slave. Ainz is SlowlySlippingIntoEvil because of his minions' influence, but Naofumi, even after using his [[SuperpoweredEvilSide Wrath Shield]], remains firmly on the side of good. Finally, while both of them have the attention of two females, Ainz can tell that Albedo and Shalltear are into him but [[CelibateHero refuses any advances]] due to seeing them as his own children, while Naofumi is just blatantly ObliviousToLove. On a humorous note, Naofumi is a college student who uses his intelligence to survive when the Melromarc Kingdom refused to give him any support. Meanwhile, Ainz has to constantly fake-out in order to make himself what he appears to be in order to get by, and is a middle school drop-out.
*** Kazuma: Both of them were summoned to their respective worlds to fight a great evil (the Devil King and the Waves), but Kazuma was implied to be one of many, while Naofumi is only one of four. They are both [[DeconstructedTrope Deconstructions]] of the StockLightNovelHero, but while Kazuma is a DeconstructiveParody, Naofumi is a full and straight forward DeconstructedCharacterArchetype. They are TheLeader in their respective parties, but while Kazuma does it because he's TheReliableOne, Naofumi does it because of his status as the Shield Hero and because his party members are his slaves. Both of their parties are formed only by females, but while Kazuma is beset by their CripplingOverspecialization and their incompetence, Raphtalia and Filo synergize well with Naofumi by covering each others' weaknesses. Kazuma is BrilliantButLazy, preferring to do as little work as possible, while Naofumi works his ass off because he knows his life depends on it. Both have roles that are derided by other adventurers for being the (alleged) weakest of the lot, only for them to prove their strengths, Kazuma by making good use of his JackOfAllTrades status and Naofumi by using all of his non-combat skills and mastering all of his shields.
*** Subaru: Both of them are suddenly sent to another world while doing everyday actions and find themselves out of depth in their new worlds. Both suffer in the beginning (Subaru because he was WrongGenreSavvy, Naofumi because he was falsely accused of a crime), but overcome that through perseverance while still suffering mental problems (PTSD for Subaru, paranoia for Naofumi). Subaru's only special power is "Return from Death", which revives him at a certain checkpoint, while Naofumi has multiple abilities thanks to his Legendary Shield. Both need the help of others in combat, but while Subaru needs it because he doesn't have any special skill beyond his SaveScumming, Naofumi needs it because he is a StoneWall with a low fighting ability. Subaru devotes himself to helping a young girl that saved him once, but Naofumi loses his trust in women due to Malty's FalseRapeAccusation (until Raphtalia gains his trust after the duel with Motoyasu). Subaru gains a comfortable place to work thanks to Roswaal, but Naofumi must survive by becoming a trader and itinerant doctor.
*** Tanya: Both were thrown from their lives in Japan to worlds at war and were given the moniker of Devil due to their enemies, (Tanya because of the actions she took during the Great War, Naofumi due to the religion of the country he was thrown into). Both of them hate the individual that took them from their lives, but while Tanya cannot act against Being X, Naofumi gets his piece of revenge on Aultcray by saving him from execution through a thorough application of CruelMercy. Tanya becomes a cog in the war machine of her new country, resulting in becoming TheFace for her fatherland's propaganda and war efforts, while Naofumi has to act as an independent hero due to his reputation being ruined by MaliciousSlander. Both quickly gain the respect and loyalty of those they lead, but while Tanya does it by making them fear her, Naofumi does it by earning their love. Tanya [[TheSociopath seems to be unable to empathize with others and only cares for her own well-being]], Naofumi initially gives that ''impression'' but is more than willing to show compassion to others truly in need.
** Albedo, Viktoriya, Aqua, Emilia, and Raphtalia (the main female characters of their respective series) are all foils to each other. The five are closer to their protagonists than any other member of their respective casts, but their impacts vary wildly:
*** With Ainz, Albedo is more of an enabler, allowing him to see the humans outside of Nazarick as beneath them. Her loyalty is without question because in her eyes Ainz is a living God who can do no wrong. Her interest in him borders on [[{{Yandere}} obsessive]] and while she would very much like a RelationshipUpgrade, so long as Ainz is a Lich and sees her as his child, it won't happen.
*** Viktoriya is often around Tanya, but her actions do little to change the Major's mindset or her objectives. She trusts Tanya and is grateful to her leadership, but she projects onto Tanya an image of a stern leader who cares for her troops, while the truth is much different. Though she knows Tanya better than most, she is still blinded by her loyalty and this projection to the Major's [[JerkWithAHeartOfJerk true personality]].
*** Despite being apart of his journey from the very start and knowing about him ''before'' he was transported into another world, Aqua's relationship with Kazuma has the least romantic undertones on both ends as the two are more LikeBrotherAndSister in regards to their dynamic due to Aqua being the most similar to him. However, Aqua also comes across as [[TheLoad more of a liability]] than the others in regards to her actually aiding Kazuma on his ventures due to having such a CripplingOverspecialization.
*** Subaru most definitely has let his feelings towards Emilia known, but [[AllLoveIsUnrequited is definitely one-sided]]. Emilia is also LockedOutOfTheLoop the most when in comes to [[ResurrectiveImmortality Subaru's abilities and experiences]], but does truly appreciate Subaru for who he is and what he has to offer [[WartsAndAll despite the flaws he demonstrates throughout their time together.]]
*** While Raphtalia sees Naofumi as a hero, she has matured enough to see the [[BrokenBird broken man]] Naofumi has become in his time in her world and he counts on her to have his back and keep him grounded. Finally, while she would also like to be something more to Naofumi, he doesn't, acknowledging that she is not a child, but still is utterly unable to see her advances as anything other than a childish crush.
** Episode 15 has Vanir and Demiurge which shows the differences between the two of them despite being devils. Vanir is a [[{{Troll}} trollish]] NobleDemon that doesn't want to hurt anyone and happily left the Demon Lord he was serving for his own goal while Demiurge is a straight-laced sadist who lives to serve Ainz.

* AscendedMeme: Aqua reenacts her [[https://pbs.twimg.com/media/ETVJhgTUMAEr50m.jpg memetic crying face]] on Season 2 Episode 10. After being yelled at by Kazuma as well.

* DoesNotLikeShoes: Just like before, Filo is barefoot when in her human form.

* EntertaininglyWrong: When Aqua confronts Subaru, Ainz and Tanya about being from Earth, she explains she can tell due to being a goddess that summoned Kazuma from Earth[[note]]along with countless others[[/note]] to fight the Demon King. Tanya then loses it and tries to attack Aqua, believing her to be Being X due her own experience with a god-like being reincarnating her in another world.
** Tanya initially suspects that Ainz is Being X.

* NiceGirl: Emilia's most defining trait in the series, to the extent that a number of other characters have commented on it.

''Isekai Quartet'' (異世界かるてっと ''Isekai Karutetto'') is a Japanese {{anime}} series that serves as a chibi-style parody crossover between the light novel series ''Literature/KonoSuba'', ''LightNovel/Overlord2012'', ''Literature/ReZero − Starting Life in Another World'', and ''Literature/TheSagaOfTanyaTheEvil'', which are all published by Kadokawa Corporation.

* AlwaysInClassOne: Averted. The main characters are shown going to Class 2. This aversion is especially bizarre, since at first, there weren't any other students shown at the school. Episode 10 revealed that Class 1 was largely empty until recently, when several more denizens of the four worlds were dropped there, including the [[LightNovel/Overlord2012 Pleiades Maids]], [[Literature/ReZero Reinhard, Felt, and Julius]], and [[Literature/{{Konosuba}} Chris]]/[[spoiler:Eris]]. Their teacher meanwhile is [[Literature/{{Konosuba}} Vanir]]. While there are no visible students from Tanya's world, a FreezeFrameBonus lists Tweet Nika Teyanen as absent from class, implying he either was meant to come but couldn't due to the rotten potato he ate, or did come and got sick ''again''. Season 2 adds [[Literature/TheRisingOfTheShieldHero Naofumi, Raphtalia, and Filo]] to the class as well. Episode 11 shows there is a Class 3 which might just be Yunyun.

** Between four LightNovel series published by Kadokawa: ''Literature/KonoSuba'', ''LightNovel/Overlord2012'', ''Literature/ReZero − Starting Life in Another World'', and ''Literature/TheSagaOfTanyaTheEvil''. They're later joined by ''Literature/TheRisingOfTheShieldHero'' in Season 2. [[spoiler:Seiya and Ristarte from ''LightNovel/TheHeroIsOverpoweredButOverlyCautious'' also cameo later in the season.]]

In the world of each of the series, mysterious buttons appear out of nowhere. When each of the series' protagonists inevitably press the buttons, them and their supporting casts are suddenly teleported to a mysterious high school. Hijinks ensue.

* {{Gainaxing}}: Rem has this more often, though it's hard to notice. However in Episode 9, Darkness in a bikini shows off her "impressive push-ups" (to the men of Tanya's unit's awe, Darkness' delight, Cocytus's discomfort, and Ram and Viktoriya's disgust).
--> '''Cocytus''': ''(SweatDrop)'' "What should I be doing here?"