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Anime / Isekai Quartet

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Introducing the Isekai Cinematic Universe!

Isekai Quartet (Japanese: 異世界かるてっと Hepburn: Isekai Karutetto) is a Japanese anime series that serves as a chibi-style crossover between the light novel series Konosuba, Overlord (2012), Re:Zero − Starting Life in Another World, and The Saga of Tanya the Evil, all published by Kadokawa Corporation.

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.

It was licensed by Funimation with an English dub being released in April 27, 2019.


The anime has examples of the following tropes:

  • A-Cup Angst: Shalltear is none to pleased when Aqua mentions that padding one's chest is something to be ashamed of, as well as being rather nervous and self-conscious when she sees Rem's chest size.
  • The Ace: Reinhardt is this to a hilariously exaggerated degree in episode 11, always having some divine protection that helps him such as Tug-of-War divine protection.
  • Always in Class One: 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 Pleiades Maids, Reinhard, Felt, and Julius, and Chris/Eris. Their teacher meanwhile is Vanir. While there are no visible students from Tanya's world, a Freeze-Frame Bonus 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. Episode 11 shows there is a Class 3 which might just be Yunyun.
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  • Arson, Murder, and Jaywalking: Ainz words his Badass Boast of the Season 1 finale this way:
    Ainz: Tanya, who do you think you're talking to? I am the lord of the Great Tomb of Nazarick, the Sorcerer King, and the vice-representative of this class!
  • Art Shift: The series uses a more limited "chibi" style than the more fleshed out art style of the four series, reminiscent of Overlord's Ple-Ple-Pleiades and Youjo Senki' s Youjo Shenki skits. Which are made by the same company.
    • In addition, the ending credits are done in a 16-bit video game style.
  • Aside Glance: Kazuma does this: first in the OP, second at the beginning of episode 2 of the show proper, and third during episode 9.
  • Aura Vision: Ainz briefly sees an aura visualisation of Subaru's "Return by Death" in his heart when they shake hands, drawing his curiosity.
  • Beach Episode: Episode 9 has the whole class go to the beach for a field trip.
  • Be Careful What You Wish For: Kazuma expresses his selfish desire to stay in this world. The BAD NEWS is that he says this in front of Tanya who will put him through Training from Hell 24/7.
  • Berserk Button: Thanks to her interactions with Being X, Tanya really cannot tolerate the presence of those who call themselves gods or who have the guise of one.
  • Beware the Silly Ones: Aqua, who is her usual ridiculous and egocentric-self, manages to make Ainz scream in pain and knockout Shalltear with her magic. For context, in the world he's from, Ainz is so utterly powerful and nigh-invulnerable compared to everyone else that calling him a God-Emperor is more accurate than not on both ends of that trope, and Shalltear is the Man of Kryptonite to Ainz himself, with all of the a absurd power that such a position comes with. Using just a "low level holy spell", Aqua manages to not only cause Ainz real damage in what seems like forever with the kind of magic he's supposed to have resistance to, but also possibly renders Shalltear fully unconscious. Even if it didn't actually hurt her (we don't see her actually get hit or affected by any kind of splash damage), the holy power it packs is enough to terrify Shalltear into unconsciousness and seriously put the rest of Team Overlord on their guard.
  • Beyond the Impossible: Ainz is an Level 100 Elder Lich, and thus, should be all but immune to any low-level holy spell despite that brand of magic being his race's one major elemental weakness. When Aqua uses the common Turn Undead spell on him, Ainz is shouting in shock and pain as this is actually affecting him much more than it normally and logically should; the spell also renders Shalltear unconscious as collateral damage. Justified since Aqua, incompetent and bumbling when it comes everyday life as she tends to be, genuinely is the Physical Goddess she constantly claims to least, when Crippling Overspecialisation isn't handicapping her.
  • Birds of a Feather: Episode 4 plays with this dynamic between Ainz & Tanya and Kazuma & Subaru.
    • Tanya and Ainz both attempt to intimidate the other with their Battle Aura over a misunderstanding that Tanya believes that Ainz must be Being X. Once they clear that up, however, they actually hit it off learning that they both originate from Japan and had similar backgrounds before being summoned/reincarnated.
    • Kazuma and Subaru initially hit it off when they start comparing how being summoned to another world wasn't as glamorous as they were led to believe. Their budding friendship breaks down though when Subaru leaves out his actual suffering experiences and unintentionally brags about living in a mansion and his Love Triangle with Emilia and Rem, much to Kazuma's jealousy.
  • Blinded by the Light: Demiurge uses a Flash spell on Kazuma when he and Tanya caught him spying on the girls in their swimsuits.
  • Brilliant, but Lazy: Kazuma, the resident and very resourceful Guile Hero of his home series, proclaims without shame that he really hates hard work, is perfectly content with staying in this world, and not doing nothing on field day while leaving the rest of his classmates to pick up the slack for him. Unfortunately, he makes the Tragic Mistake of saying this outloud in front of Tanya.
  • Brutal Honesty:
    • Self-inflicted. Subaru introduces himself as both clueless and broke.
    • During her introduction, Beatrice doesn't bother to hide what she thinks of the whole situation.
      Beatrice: I'm Beatrice, I don't think it's really nice to meet any of you.
    • Seems to be a theme with the Re: Zero characters, as in the next episode, Rem talks about her crush on Subaru, with Subaru sitting right next to her.
      Rem: When you fall in love, it doesn't matter how long you've known someone! [...] I've barely known Subaru-kun for any length of time at all, and he's very important to me.
  • Call-Back:
    • Let's say this isn't the first time both Aqua and Megumin felt the uncontrollable urge to press a mysterious button, despite not knowing what it could do.
    • In episode 2, Subaru introduces himself to the class in exactly the same way that he first introduced himself to Emilia. The Overlord cast also reprise the way they presented themselves before Momonga/Ainz.
    • Why did Aqua's attack only damage Ainz where it knocked out Shalltear? Because as Ainz's stated before, he has a higher Magical Defense than her.
    • Episode 9 features Darkness being forced to do push-ups, with her boobs bouncing all over the place. Something that already happened in the first Konosuba OVA (though, unlike Kazuma, Cocytus probably didn't have any perverse ideas in mind when he ordered this).
    • Demiurge pretty much instantly figures out the world's gimmick, and naturally assumes Ainz did too, resulting in Ainz having to repeatedly fish for information on "that thing" while internally screaming that he doesn't know what Demiurge is talking about, similar to the scene in Overlord when Ainz first discovers "his" master plan to conquer the world and trying to figure out "that one time" when he gave Demiurge that idea.
  • Cassandra Truth: Tanya, despite her hatred of self-proclaimed gods, never registers Aqua's proclamations of being a goddess because she acts too silly to be one. Once she actually does register Aqua as being a Goddess she tries to kill her under the suspicion that Aqua is Being X before being calmed down and realizing that Aqua's too stupid to be Being X.
  • Class Representative: After drawing names, Emilia becomes this to this class with Ainz and Albedo being vice reps.
  • Cliffhanger: The show ends with the group discovering that the way back home was a lie and that they are still stuck in this world. While they decide that they don't mind it that much, Rosswaal reveals that Transfer Students will be joining the class, with the credits rolling when he asks them to enter. The last scene is even more obvious with Rosswaal holding up a sign that reads, "Season 2 coming soon".
  • Clingy Jealous Girl:
    • Like always, Albedo was beyond furious when it looked like Tanya was asking Ainz out.
    • When Albedo rushes out after class to get to Ainz and Tanya's "date", Viktoriya also rushes out to do the same thing, and when she gets there interrupts them to offer to take Tanya to get croquettes.
  • Cloudcuckoolander's Minder: As usual, Kazuma does his damnedest to make sure his party's antics don't publicly embarrass him or get them all killed.
  • The Comically Serious: Cocytus goes along with the crossover's silliness with all the seriousness he packs in his home series.
  • Comically Invincible Hero: Reinhard thanks to his "divine protection" blessing.
  • Commander Contrarian: Aqua will always oppose any idea or suggestion that comes from Ainz, not because of the ideas themselves, but because she refuses to accept anything that comes from an undead.
  • Compelling Voice:
    • Erich von Rerugen shows the ability to give a command that enforces the school rules and for others such as Beatrice and Albedo to be forced to obey whether knowingly or not.
    • Demiurge has his Command Mantra spell from his home series that he attempts to use on Kazuma and Tanya. While it works on Kazuma, Tanya doesn't even recognise its existence and doesn't know why Kazuma can't get up from the floor.
    • Following up with the above entry, Tanya uses her authoritative voice on Kazuma to make him stand up at attention so he doesn't go lie down and they can get actual work done. This puts Demiurge on edge as he recognises it as something similar to a control spell.
  • Continuity Cameo: The statue Megumin uses as a target for her Explosion spell in Episode 5 is that of Pandora's Actor.
  • Continuity Nod:
    • Episode 5 has Kazuma namedrop the Winter Shogun after Ainz makes it snow, stating that Cocytus resembles it.
    • In episode 8, it is brought up that Albedo is surprisingly a virgin despite being a succubus.
      • In that same episode, Kazuma questions if she's capable of doing an Erotic Dream like the succubi from his world and it's also brought up once again that Eris and Shalltear pad their chest.
  • Cringe Comedy: The majority of episode 5 is this with the characters being forced to participate in a talent show that they didn't really prepare for.
  • Crossover: Between 4 series being licensed by Kadokawa: Konosuba, Overlord (2012), Re:Zero − Starting Life in Another World, and The Saga of Tanya the Evil.
  • Death from Above: Courtesy of Puck in episode 10.
  • Death Glare:
    • The members of Nazarick do this to anyone who threatens Ainz physically, such as Aqua, or in Albedo's case anyone who might seduce Ainz.
    • Even when facing Ainz's Despair Aura, a skill that causes the level 100 Guardians of Nazarick to barely maintain their composure, Tanya doesn't even flinch and gives a glare to Ainz that terrifies him enough to trigger his Emotion Suppression.
  • Denser and Wackier: Each episode is only around ten minutes and seems to capture only the comedic aspects of each of the series.
  • Didn't See That Coming: Ainz definitely didn't expect that Aqua's Turn Undead, a low level spell according to him, would bypass all his immunities and protections and cause a lot of harm.
    Ainz: A normal Turn Undead from her packs this kind of power?
    • It is very clear that no one, least of all the cast of Konosuba, expected the appearance of The Mobile Fortress Destroyer during the last event of field day.
  • "Do It Yourself" Theme Tune: Both the opening and the ending are sung by the main characters from all four series, with Kazuma, Subaru, Ainz, and Tanya singing the opening, and Aqua, Emilia, Albedo, and Tanya again singing the ending.
  • Dope Slap: Kazuma punches Aqua's head twice over when she attacks the Nazarick group.
  • The Dreaded: Tanya, the rest of the Youjo Senki cast is horrified of her and the number grows as the show goes on.
  • Dude Looks Like a Lady: Mare, the characters not from Overlord all think he's a girl and the Overlord cast hasn't taken the time yet to explain otherwise.
  • Dumbass Has a Point: Aqua, who is still as ditzy and lacking in sense in this show as she is in her home series, attacks Ainz and his underlings on the basis that they are as evil as their appearances would suggest. As fans of Overlord can attest to, this line of reasoning couldn't be closer to the truth.
  • Effortless Amazonian Lift: In Episode 4, both Rem and Darkness were able to run while carrying Subaru and Kazuma, respectively, without slowing down, and using a single arm to hold them.
  • Entertainingly Wrong: 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 Earthnote  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.
  • Everyone Has Standards: Aqua might not like Albedo for being allies with an undead like Ainz but even she won't make fun of Albedo for being a virgin because she's saving herself for the person she loves.
  • Evil Laugh: Tanya is clearly having the time of her life watching Kazuma run around like a headless chicken as he runs away from Puck's magical blasts.
  • Excited Title! Two-Part Episode Name!: Though only the first part ends in exclamation point.
  • Eye Catch: While generally averted, Episode 5, which puts a lot of focus on the Konosuba characters, uses the Eye Catch from that series (with the characters shouting "Ise-Quar!" instead of "Konosuba!")
  • Fantastic Racism: Like in her home series, Aqua is instantly hostile towards Ainz and his group just because most of them are undead.
  • Final Death: Chris informs Aqua, Kazuma and Darkness that they aren't able to revive in this world. Subaru, eavesdropping, wonders if it includes his "Return by Death". He quickly discovers that, even if "Return by Death" can't bring him back, the penalty for trying to tell others still works, so he still can't talk about it.
  • Foil: Each main protagonist of the four series in this crossover can be considered one to each other:
  • Foreshadowing: That scene in the opening where Tanya kicks an exhausted Kazuma as they are running? That was signalling the Training from Hell she puts him through after he declared his intentions to be The Load on field day.
  • Four-Philosophy Ensemble: The four main isekai protagonists, as much as they are in character here from their respective series, cover the moral spectrum quite well based off their personality traits and actions:
  • Four-Temperament Ensemble:
    • Subaru is Sanguine — the loud, compassionate immortal who tries his best regardless of the situation.
    • Tanya is Choleric — the irritable, task-oriented worker, infuriated by the foolishness of those around her.
    • Kazuma is Melancholic — the most grounded and introspective member of the isekai members.
    • Ainz is Phlegmatic — the least emotional yet most observant and ambitious of the lot.
  • Friendless Background: Even on another completely different world in addition to having three other casts of characters around her, Yunyun STILL has no friends.
  • The Friend Nobody Likes: 10 episodes in, while several members of the Overlord, Youjo Senki, and Re:Zero casts have been able to form friendships with one another, the main cast of Konosuba clearly haven't made any real progress at bonding with the others and at times, barely seem to be even tolerated. Aqua constantly antagonizes the cast of Overlord for being undead and is treated like something of a joke by everyone else, Megumin has been largely Out of Focus, and Darkness's masochism clearly repulses and disgusts just about everyone. Out of everyone though, it's Kazuma who probably has the worst relationship out of everyone. His budding friendship with Subaru collapsed immediately when he grew jealous of Subaru's situation (and him not being aware of how awful Subaru's life is in Re:Zero). He's genuinely terrified of his fellow Discipline Committee members, Demiurge and Tanya, the latter turning into a Drill Sergeant Nasty to get him to comply. And when offered the chance to return to his world, he was the only person in the class who outright refused, which resulted in him being punished by being put into a Training from Hell.
  • 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: (Sweat Drop) "What should I be doing here?"
  • Green-Eyed Monster: Kazuma becomes one for Subaru of all people when they talk about their situations in episode 4. Because Subaru left out all the horrible suffering and deaths he suffered in adventures, it just sounded like he lives in a mansion surrounded by cute girls.
  • Hate at First Sight: As expected, Aqua instantly hates the Overlord cast for being undead and demons. She even attacks them in episode 2.
  • High School A.U.: Could be considered this, since it features all involved parties attending high school, even if some of them are grown adults. Also, it is a very rare official High School A.U..
  • 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.
    • That being said, Subaru himself gets a moment.
    Subaru: Combat Maids? That's too much.
    Ainz: I don't want to hear that from the guy with the Demon Maids.
  • I Have No Son!: Played for Laughs. Despite being Pandora's Actor's creation, Ainz continuously denies being his father despite the former's insistence on calling him such.
  • I Need to Go Iron My Dog: In episode 12, class 1 decides to fight the teachers instead of The Mobile Fortress Destroyer leaving it to class 2/the main protagonists. Subaru complains that they have the far harder task and asks why class 1 doesn't do it when they have Reinhardt. Reinhardt just says his divine protection of not stealing the screentime prevents him from doing this which Subaru once again calls bull on.
  • Innocently Insensitive: Downplayed in episode 8 as Aqua unintentionally insulted Shalltear when she was intentionally insulting Eris for padding her bra.
  • Insistent Terminology:
    • Ram keeps calling Subaru, Barusu. This eventually causes confusion for Serebryakov in episode 9.
    • Pandora's Actor refers to Ainz as his father due to being personally created by him.
  • Interspecies Friendship:
    • In Episode 3, Albedonote  and Remnote  befriend one another.
    • Downplayed In Episode 4, as while Tanyanote  becomes friends with Ainznote , Ainz is a former human that been placed into his game avatar, so really it is a normal friendship between two humans.
    • In Episode 6, Tanya also becomes friends with Demiurgenote .
    • In Episode 7, Beatricenote  becomes close with Marenote .
  • Ironic Echo Cut: Ainz comments that only a kid or a simpleton would press a suspicious red button that appeared out of nowhere. Cut to the Konosuba group, where Kazuma is holding back Aqua from pressing the button, only for Megumin to press it instead.
  • Kimodameshi: It was discussed in episode 8 and happens in episode 9 but most of the characters aren't impressed, with the Youjo Senki cast even saying they find Tanya far scarier than anything in the test of courage. They're proven correct when Tanya enters Unstoppable Rage and causes a Mass "Oh, Crap!" among the entire cast.
  • Large Ham: Episode 11 has a glorious team up of the four series' resident large hams of Roswaal, Vanir, Pandora's Actor .... and Rerugen as the teacher group for field day
  • Leaning on the Fourth Wall: In Episode 4, Kazuma and Subaru complain that in Isekai stories, the main character is overpowered, wins all his fights easily, and has a harem of beautiful girls, and how their experiences are nothing like that.
  • Lighter and Softer: Is much, much more lighthearted and soft when it comes to tone and content in regards to three of the series featured in this crossover. This kind of setting however, is par for the course when it comes to Konosuba.
  • The Load: Hilariously invoked and deconstructed by Kazuma. He makes it clear that he is very content with staying in the current world and planned on doing nothing on field day, regardless of how much of a Jerkass he looks like deliberately hindering everyone's chances in going back home. This is taken further by the fact that Tanya refuses to have ANY of this laziness hinder the class as a whole and immediately proceeds to put Kazuma through a Training from Hell in order to beat this attitude out of him. And it works as he does try his best on the field day.
  • Loads and Loads of Characters: Inevitable, given that it's a crossover between four series. Just the protagonists and the female leads form a group of eight, and goes past twenty if we include the rest of the main characters.
  • Loads and Loads of Rules: Tanya and Demiurge decide that their first official action on the Disciplinary Committee is to create a list of as many rules for the class to use as possible, deciding the more the better. This is part of what leads to their Odd Friendship.
    Tanya: Rules! Rules first, then freedom. That's how it's going to be!
  • Love at First Sight: Discussed in episode 3. Albedo uses this as an excuse to be preemptively jealous of any girl (or anyone, if her comments about "age, race and gender don't matter" is any indication) that get close to Ainz, with Rem agreeing with her, using her own crush on Subaru as an example. This became the foundation of their Odd Friendship.
  • Man of Kryptonite: The goddess Aqua most definitely qualifies, as she is one of the very few characters to seriously hurt the undead Ainz and the first and only character to render the vampire Shalltear completely unconscious in one go (though we don't see the actual spell hit her, implying either splash damage or her scared half to death by how unexpectedly powerful the spell is).
  • Mass "Oh, Crap!":
    • When Tanya briefly goes into a Unstoppable Rage, the explosion of power she unleashes is likened to an earthquake, as well as pegged as greater than an 8th Tier Spell by Ainz, and causes several of the cast to go catatonic or to put everyone else in the greatest concerns. It causes the Floor Guardians to be put on edge, and even Roswaal loses his perpetual smile in the shock.
    • Everyone, but most notably the Konosuba cast give another one when the Teachers reveal and activate the Mobile Fortress Destroyer.
  • Mirthless Laughter: Ainz and Subaru indulge in this together while standing next to each other awkwardly during the OP.
  • Mistaken for Badass: Like in his home series, it happened to Ainz again. While Ainz is very powerful, he's just a regular person, making it hilarious that Tanya thinks he's Being X, a god, due to his imposing presence and aura, all the while ignoring Aqua, a real goddessnote .
  • Mood Whiplash: Albedo goes from burning with anger upon seeing Tanya wanting to speak with Ainz in private (thinking she wants to seduce him) to holding hands with Rem and sweetly declaring how well they're going to get along when the latter agreed with her about Love at First Sight.
    • In episode 10, one scene has Subaru learn the hard way that the penalty for talking about Return by Death is very much still in effect (complete with the infamous "Call of the Witch" BGM)...then immediately returns to comedy as he, Ainz and Tanya nearly get stampeded by Hamsuke and a giant skeleton knight.
  • Mundanization: Four isekai protagonists, all originally from Japan, are whisked away from their colorful fantasy lands and taken to a brand-new world where they must.... attend a Japanese high school.
  • Murder Is the Best Solution: When trying to figuring out what's going on, Albedo suggests Ainz to kill everybody else, though he thankfully turns said suggestion down.
  • My Friends... and Zoidberg: Meta-wise, while all four works are Isekai series produced by Kadokawa, Konosuba stands out amidst the other three for several reasons:
    • While the other three works are dramatic with hints of comedy that play with standard Isekai tropes to an extent, Konosuba is a parody of the Isekai genre that frequently deconstructs the tropes in the genre with a large focus on comedy.
    • While the other three works all have comparatively large casts of at least six characters with numerous supporting characters appearing, Konosuba only has four main characters, with three supporting characters and a minor character appearing so far.note 
    • While the other three works have largely managed to form inter-class friendships with other works, Konosuba's cast is largely The Friend Nobody Likes, due to their eccentricities putting many of the other characters off or annoying them, in particular Aqua's overzealous attempts to purify the Overlord class.
    • While the other three works all have characters highly skilled in their own worlds, typically in high positions of power, the cast of Konosuba are run of the mill adventurers struggling to get by, with an extreme party imbalance.
  • Nerves of Steel:
    • Tanya, eleven-years old at this point of her second life, stares down Lord Ainz without a hint of hesitance or fear.
    • Ainz notes that Subaru, a seemingly ordinary human, witnessed an explosion of magical aura from Tanya right in front of him and didn't faint and remained standing, even when several others got knocked out or surprised. He ponders what mental stress Subaru must be used to living under to handle such power.
  • No Good Deed Goes Unpunished: In episode 5, when it's Darkness' turn in the talent show she asks for help. Warren volunteers and due to Darkness being ... Darkness, it makes the entire class think he's assaulting her, calling him scum as a result. Subaru steps up to tell Warren off...only for him to fall victim to the same misunderstanding as well.
  • No-Harm Requirement: How Demiurge interpreted the rules Roswaal stated. Thinking that anything that would hinder their school life is prohibited and as punishment they wouldn't be able to return to their respective home worlds. Based on Roswaal's smile when Demiurge explained, it's probably accurate.
  • No-Sell:
    • Tanya seems to have some form of immunity to powers from the Overlord cast. Not only was she unfazed by Ainz's Despair Aura passive, but she didn't even notice Demiurge's Commmand Mantra and got confused as to why Kazuma was suddenly on the floor.
    • Subaru himself could maintain his footing and consciousness against Tanya's rage-burst of magical power, of which Ainz notes to be stronger than an 8th Tier Spell from Yggdrasil, due to all the mental stress he's used to in his home series.
  • Not So Different: Kazuma and Ainz are both Genre Savvy characters who understand the trappings of the Isekai genre, and such both come to the exact same conclusion when Tanya and her company make their introductions, the difference being that Kazuma mutters his observation out loud and Ainz internally narrates it as in his home series.
    Kazuma/Ainz: Uwah...They're from some war world.
  • Not What It Looks Like: In episode 5, Darkness tried to show off her durability in the talent having someone whip her. Warren volunteered to help without knowing what he was getting into but due to how Darkness worded it, it made it sound like Warren regularly whipped women which made the entire cast call him trash. Subaru was later dragged into it when he attempted to call Warren out.
  • Pet the Dog: Despite showing nothing but contempt for the Overlord cast, Aqua jumped to Albedo's defense when Shalltear was mocking her for being a virgin succubus, going on a rather uplifting speech about how there's nothing wrong with saving yourself for the right person.
  • Power Creep, Power Seep: Parodied with Ainz noting that Aqua is a goddess capable of hurting him, one of the most powerful beings in his series, with a low-level spell and yet was easily Dope Slapped into submission by Kazuma with zero fanfare due to their world being an Affectionate Parody instead of a serious one like his.note 
    Ainz: A goddess who can make me feel pain even at level 100. And a human who casually punches such a goddess. This world...has some serious power balance issues!
  • Odd Friendship:
    • Albedo takes a liking to Rem when she shares her belief in love regardless of how long you've know a person.
    • Tanya and Ainz become good friends after discovering they were both former Salarymen from Japan, having a private talk where they shared interests and experiences of their first life, and just generally feeling at ease at having someone to talk to about this. Tanya enjoyed the talk so much that she left smiling up into the next morning.
      Erich: That demon who wears the skin of a girl, smiling? What's going on?
    • Tanya and Demiurge develop a bond with one another when selected as members of the Disciplinary Committee not only due to their mutual liking and respect of Ainz, but also because they agree that the classroom needs a detailed structure and list of rules first before anything else.
    • It becomes inverted with Kazuma and Subaru however. Although they initially took great joy in finding one another, once they explained their respective situations, Kazuma becomes enraged and declares Subaru his enemy after discovering that not only does he live in a mansion, but he's also surrounded by beautiful girls, two of which are maids and one of whom has feelings for him, gets to go after the girl he loves, and all the while declaring his life hard which Kazuma can't comprehend. To be fair to Subaru, he can't explain why his life is hard lest the person who hears it dies.
      Kazuma: "You Harem-having bastard!"
    • Beatrice becomes less cold to Mare when they're both Librarians, saying there is something relaxing about Mare. She also insists on accompanying him to school when they meet up, all in her usual Tsundere way.
  • Slasher Smile: Tanya gives quite the deadly one towards Kazuma before and during his Training from Hell.
  • Smitten Teenage Girl: Rem for Subaru, no matter what he does she finds amazing.
  • Sneeze Cut:
    • After dealing with Beatrice, Rerugen says that he shouldn't underestimate little girls, since he knows some demons who "wear the skins of little girls". Cue Tanya sneezing.
    • After going through the Test of Courage, both Viktoriya and Weiss mention that their world was scarier, though Weiss specifically mentions that Tanya is scarier. Viktoriya admonishes him, worried about Tanya, and both accuse the other of being the one who said it. Again, cue Tanya sneezing.
  • Spot the Thread: When confronted in private by Tanya and she mistakes him for Being X, Ainz deduces from the details she spouts that she is actually from Earth. One can actually see the moment when he figures it out.
  • Stronger Than They Look:
    • Aqua as always. Despite being a narcissistic, whiny idiot most of the time she's still a goddess as Ainz realized when her Turn Undead, which he stated was weak spell, seriously hurt him. Aqua could legitimately solo a good chunk of the Tomb of Nazarick, considering Ainz' forces are comprised of mostly undead or evil monsters.
    • Tanya, surprisingly. Not only was she unaffected by Ainz' Despair Auranote  and didn't even notice Demiurge's Command Mantranote , but when she got angry at Aqua she released an aura of magical power that was likened to an earthquake and Ainz notes to have the power to exceed that of an 8th Tier Spell by Yggdrasil's standards.
  • A Taste of Their Own Medicine: In episode 8, Shalltear opts to embarrass Albedo by revealing to Kazuma and Aqua that Albedo is a virgin succubus. However, this causes Aqua to go on a rant about how one shouldn't be ashamed of saving yourself for the one you love, or anything else for that matter, then adds an exception for padding one's chest (specifically referring to her fellow goddess Eris but unknowingly catching Shalltear in the crossfire), resulting in Shalltear herself being humiliated instead of Albedo (much to the latter's mirth).
  • This Is Gonna Suck: Once the cast of Re:Zero enter the class, Kazuma utters this.
  • Trapped in Another World: The main joke of the series is that four Isekai protagonists and their supporting casts have now been subjected to an Isekai inside their own Isekai stories, only this time to a shared comedy setting.
  • Training from Hell: When Kazuma makes it clear that he'll be The Load on field day, Tanya decides to "fix" this attitude the 203rd Mage Battalion way.
  • Underestimating Badassery: Ainz is dismissive of Aqua (understandably), seeing her Turn Undead attack as low level...and in the process of being hit by said attack, Ainz is screaming in genuine pain. This legitimately causes an Oh, Crap! reaction amongst Team Overlord when they realize how dangerous Aqua is.
  • Unsettling Gender Reveal: Mare finally reveals that he's a boy to the shock of Megumin, Warren and Beatrice in episode 9.
  • Unstoppable Rage: Anytime Tanya thinks she finds Being X, she explodes in rage. After learning that Aqua is a goddess, she unleashes enough magic power to horrify her squad and even unsettle the Overlord cast.
  • Violently Protective Girlfriend: Well, minus the "girlfriend" part; when Rem heard about Hamusuke chewing on Subaru's head, her response was to whip out her flail and shout "let's defeat this monster together!"
  • Wacky Homeroom: It goes without saying, given that the students in this classroom are a perverted shut-in, a sociopathic little girl, a lich, twin oni maids, a depraved succubus and a Chuunibyou obsessed with explosions, among others.
  • Wham Line: The first season ends with one.
    Roswaal: By the way, I forgot about something important. Transfer students will be joining the class!
  • What Does This Button Do?: When Kazuma's group finds the button, Aqua wants to press it despite Kazuma warning her it might be dangerous. While he's holding her back, Megumin presses it.
  • Wrong Context Magic: Reinhard's divine protection. Thanks to this blessing, he can practically No-Sell everything and everyone sent his way. This is best shown when Kazuma's Steal ability had no effect whatsoever.

Example of: