History YMMV / AssassinationClassroom

** [[spoiler:[[BigBad Shiro]], real name [[ItsAllAboutMe Kotaro Yanigasawa]], was a MadScientist focused on utilizing {{Antimatter}} in a human body, and the reason [[Characters/AssassinationClassroomKorosensei Koro-sensei]] may [[WhyAmITicking destroy the world]]. To this end, he used the famed assassin the God Of Death as a human guinea pig in painful experiments, using his own fiancée as their liaison since Yanagisawa figured she was worthless as a hostage. When the God of Death escaped, destroyed the lab and took Yanigasawa's eye, the scientist formed the identity of Shiro and plotted his vengeance. He implanted a boy named Itona with the same tentacles and later [[YouHaveOutlivedYourUsefulness abandoned him to die when he'd served his purpose]]. Mutating the assassin's former protege into a monstrosity, he tested his new success by having him annihilate a giant building--and anybody inside--before attacking Koro-sensei and his students. Having the second God of Death attack Koro-sensei, Yanagisawa opted to then have the students attacked, gloating how he'd kill every single one of them painfully and Korosensei would be forced to watch his class die before dying in despair. When his former fiancée's sister attempted to help Korosensei, Yanagisawa had her impaled through the chest and gloated how he'd intended to use her as a "[[ReplacementGoldfish replacement]]" for her sister.]]

** With ''Manga/JoJosBizarreAdventure'' due to the series' tendency to combine over the top, characters, humor and action with some serious drama. There's also the fact that Matsui was inspired by the JJBA franchise. Some have eveen seen ''Assassination Classroom'' as a SpiritualSuccessor to JJBA since JJBA no longer runs in Shounen Jump. It also helps that both seasons of the anime aired while a JJBA season was airing.

** There are a few ''Assassination Classroom'' fans who are also fans of ''Manga/AkameGaKill''. For the most part this seems to be a result of the fact that both shows are centered around assassins but with a tone of black humor and the anime for ''Assassination Clasroom'' aired right after the anime adaptation of ''Akame ga Kill!'' finished.

* AudienceAlienatingPremise: Even though the series is actually quite popular and regularly appears in the bestselling graphic novels lists, American publishers were squeamish to publish in first place because the premise of "armed students went all out to murder their teacher (who is an omnicidal alien teaching them their killing ways)" didn't feel adequate in a post-Columbine atmosphere.

** The elusive [[MasterOfAll Reaper]], real name Ryushi Korogane, raised himself from an impoverished child to the [[FromNobodyToNightmare most feared and brilliant assassin]] in the world. Raising the son of one victim as his apprentice, the Reaper expanded his business until his apprentice betrayed him to the vile scientist Kotaro Yanagisawa. Falling in love with the abusive Yanagisawa's fiancée, the Reaper eventually breaks free of captivity by slaughtering Yanagisawa's guards when his lover is fatally wounded. Knowing the experiments will cause him to self-destruct along with the earth within a year, the Reaper becomes caring a teacher of [[Characters/AssassinationClassroomClass3E troubled youth]], "[[Characters/AssassinationClassroomKorosensei Koro-sensei]]", grooming their self-confidence while imparting the skills to kill him and save the world.

* AudienceAlienatingPremise: Even though the series is a light-hearted sci-fi comedy with an awesome SaveOurStudents plot, it ''does'' hinge on a classroom full of kids learning how to kill their teacher with guns, knives, and the occasional explosives. Thus, the series' title and premise has earned concerns from some Americans, especially given the worryingly large number of school shootings in the country. The replies under [[https://twitter.com/ToonamiSquad/status/1530768395762737152 this tweet]] by Creator/{{Toonami}} promoting the show is one example.

** [[BigBad Shiro]], real name [[ItsAllAboutMe Kotaro Yanigasawa]], was a MadScientist focused on utilizing {{Antimatter}} in a human body, and the reason [[Characters/AssassinationClassroomKorosensei Koro-sensei]] may [[WhyAmITicking destroy the world]]. To this end, he used the famed assassin the God Of Death as a human guinea pig in painful experiments, using his own fiancée as their liaison since Yanagisawa figured she was worthless as a hostage. When the God of Death escaped, destroyed the lab and took Yanigasawa's eye, the scientist formed the identity of Shiro and plotted his vengeance. He implanted a boy named Itona with the same tentacles and later [[YouHaveOutlivedYourUsefulness abandoned him to die when he'd served his purpose]]. Mutating the assassin's former protege into a monstrosity, he tested his new success by having him annihilate a giant building--and anybody inside--before attacking Koro-sensei and his students. Having the second God of Death attack Koro-sensei, Yanagisawa opted to then have the students attacked, gloating how he'd kill every single one of them painfully and Korosensei would be forced to watch his class die before dying in despair. When his former fiancée's sister attempted to help Korosensei, Yanagisawa had her impaled through the chest and gloated how he'd intended to use her as a "[[ReplacementGoldfish replacement]]" for her sister.
** [[SadistTeacher Akira Takaoka]] is a [[DrillSergeantNasty brutal military trainer]] known for torturing his students with sadistic relish while he [[MindRape breaks them mentally]]. During his brief stint as Class E's trainer, he is willing to [[WouldHurtAChild brutalize any unruly student]], regardless of gender. After being ousted, Takaoka devotes himself to revenge. After stealing money to buy a bio-weapon and hire hitmen, he infects Class E with a virus to cause a [[CruelAndUnusualDeath horrifyingly painful death]] as they slowly suffocate under the weight of tumors. The few students who escape this fate are targeted for even worse fates as Takaoka intends on [[BuriedAlive burying Kayano alive]] in cement in a bathtub full of material lethal to the kids' teacher Korosensei, which would [[SadisticChoice force him to sacrifice his life to save her]]. To drive in his victory, he even destroys the antidote while gloating he might use the money to purchase middle-school aged kids to murder on a regular basis as some twisted celebration.

* AcceptableTargets: Overachievers. Almost everybody in Class-A is an InsufferableGenius with a huge sense of self-importance and a strong desire to belittle the less-advantaged.

* CompleteMonster:

* CriticalResearchFailure: It's stated in the series that Mach 20 is "twice the speed of sound". Mach 1 ''is'' the speed of sound, so Mach 20 would be twenty times faster.

* AuthorsSavingThrow:
** Koro-sensei [[spoiler:turning out to be the true God-Of-Death]] is seen as this for some people who were disappointed that [[spoiler:the "fake" one seen in the God-of-Death arc was hyped up only to be an absolute joke by the time the arc concluded, though it's most likely that the author had this in mind from the start]].
** Many people called out that Nagisa's dilemma of his blood lust and ease to be a assassin was brushed aside very quickly. Several chapters later refocuses on it to what he should do to help.
** In the manga, [[spoiler:the God-of-Death apparently kills Lovro]], only for him to [[UnexplainedRecovery show up alive later with zero explanation]]. The anime answers this by explaining that [[spoiler:the God-of-Death deliberately left Lovro alive so he could spread his reputation]]. It also helps that his [[spoiler:supposed killing of Red Eye only for the assassin to turn out to have survived as well]] was left out of the adaptation. The changes to both events, for anime viewers at least, kept the character from suffering the same BadassDecay that the readers felt once his StoryArc was done with.

* DiagnosedByTheAudience:
** There is ''something'' off about Nagisa and Karma lampshades this InUniverse.
*** He isn't intimidated by having to wield a real knife, let alone threaten someone's life, even though it's specifically pointed out that he should be. Yet he isn't generally callous or manipulative like a sociopath -- he is just cold and calculating, as though he were a veteran hitman. Not only does he show little hesitation, but he is clear-minded enough to attack using the dull side of the blade.
*** His early interactions with Karma are also not quite ordinary. Most would be rather disturbed by the latter's claims of wanting to kill his teachers, but Nagisa, who's already used to his exaggerations, remained calm the whole time, barely showing any reaction.
** As shown how extreme Principal Asano is by proving his current education philosophy right after the death of one of his former students hints at the severe emotional imbalances as a result of repressed grief and severe Post-Traumatic Stress Disorder. Also, he can be considered a bit odd prior to his past as a cram school teacher.
** Nagisa's mother, Hiromi, is ''definitely'' unwell in her EstablishingCharacterMoment. Due to her ControlFreak tendencies and severe mood swings, it's possible that she's suffering from BPD or Mania Disorder as a result of her own miserable childhood consisting of controlling, [[EducationMama academic-success driven parents]], being unable to enjoy certain hobbies, and failure to succeed the goals she set for herself.

** As shown of how extreme Principal Asano is by proving his current education philosophy right after the death of one of his former students hints at the severe emotional imbalances as a result of repressed grief and severe Post-Traumatic Stress Disorder. Also, he can be considered a bit odd prior to his past as a cram school teacher.
** Nagisa's mother, Hiromi, is ''definitely'' unwell due to her ControlFreak tendencies and severe mood swings as a result of her own miserable childhood consisting of controlling, EducationalMama parents, being unable to enjoy certain hobbies, and failure in the goals she set for herself. Possibly having BPD or Mania Disorder.

** [[spoiler: The God of Death, more specifically, the "Death" part.]] During his screentime, [[{{Irony}} he fails to kill any named characters.]] [[UpToEleven By chapter 117]], [[spoiler: the people he killed to establish his badass cred were shown to both have survived. However, it is later revealed that ''this'' God of Death was merely the apprentice to the ''previous'' God of Death. The previous God of Death was ''Koro-Sensei'']].

* UnintentionallySympathetic: In the manga, Kaho is meant to be a DirtyCoward BitchInSheepsClothing who deserves the humiliation she receives. Several readers, however, think she comes off as someone trapped in a relationship with an [[BastardBoyfriend abusive boyfriend]] and thus have more sympathy for her fearfulness, feeling that Class E's [[DisproportionateRetribution retribution on her was disproportionate to her alleged crimes.]]

* {{Narm}}:
** Nagisa's angry shouting at Koro-sensei over rejecting Sugino's feelings is pretty serious, but [[http://www.animevision.co.uk/fun/twia/21/assclass02b.png Nagisa's over the top face]] almost looks more of a ComicalAngryFace.
** [[spoiler: Koro-sensei's death]] is quite possibly the series' biggest TearJerker, but when the anime cuts to [[https://web.archive.org/web/20190717041528if_/https://i.ytimg.com/vi/jD9FLhN-c4g/hqdefault.jpg Nagisa's blubbering, crying face]] it's a bit hard not to giggle.
** Crossed with NightmareRetardant: God of Death when unmasked is supposed to be terrifying because [[spoiler: he peeled his own flesh off so that he could disguise himself easier]], but his big bulging eyes make him look too cartoonish to be taken seriously, not to mention the fact that he resembles ComicBook/RedSkull.

** In the English dub, Irina does not teach English to the students, but instead social skills and grammar (and their use in assassinations). For example, in episode 10 instead of discussing how Japanese speakers have trouble with the English L and R, she's teaching how icebreakers are used by assassins.

** The English subtitles for the movie's release in Asia has Korosensei renamed as "UT"(short for "Unkillable Teacher") and Ritsu renamed as "S.T.A.R."(Self-Thinking Artillery Robot).

** Irina's sexual assault of her students would be seen as horrific if this wasn't Japan.

** The English dub of the [[https://www.youtube.com/watch?v=USGZ57ZOpC8 Korosensei Drawing Song]] manages to retain everything in translation and get the lyrics to rhyme.

* AudienceAlienatingPremise: Even though the series is a light-hearted sci-fi comedy with an awesome SaveOurStudents plot, it ''does'' hinge on a classroom full of kids learning how to kill their teacher with guns, knives, and the occasional explosive. [[UsefulNotes/{{Columbine}} Obviously]], it won't fly high in North America and other countries with histories of student rampage. Emphasis on "high": NoExportForYou has been (for now) {{averted|Trope}}. Even without the assassination plot, there is the issue of an entire classful of kids being discriminated against by the rest of their school.

* TheScrappy:
** Hiromi Shiota, Nagisa's mother, was instantly hated by the fans when she was introduced in [[spoiler: Chapter 112. She uses Nagisa to live her life anew, denies him control over his own life and gives him no say in his future, so as to not make the mistakes she made. She also refuses to acknowledge his gender, and immediately goes into a rage when he makes any sort of defiance against her, even if it was unintentional on his part.]] The next few chapters with her show just how deluded she is about everything. She's so detestable that she would easily qualify as a HateSink instead of TheScrappy, if not for the way Nagisa [[HonorThyAbuser handled things in the end]], making her a massive case of KarmaHoudini and EasilyForgiven, so it's unclear if she was actually intended to be hated as intensely as she is. While she did mellow out after her introductory arc, it's hard to forgive how she treated Nagisa and the fact that she [[spoiler: attempted arson and planned to frame her son for it]].
** A good part of the fandom used to see Kayano as this, at least to the extent that [[TheyWastedAPerfectlyGoodCharacter she was just there all the time and not very interesting]]. [[spoiler: [[RescuedFromTheScrappyHeap Then chapter 128 happened.]]]]

*** What? There are plenty of people in the US who catch insects in the wild, either to kill and pin or keep as pets. There are even [[https://bugsincyberspace.com/ websites selling live insects]]. The only way it would be considered poaching is if it was a protected species or in a national park, and even then the only people likely to care would be the government and scientists.

** Despite the major build up of the new students transferring into Class 3-E, Ritsu is mostly only present as comic relief while Itona fades into obscurity moments after becoming an official member of the class.