History YMMV / ACertainMagicalIndex

** The duo of Mikoto '''Misa'''ka and '''Misa'''ki Shokuhou have been called "MisaMisa" as they [[VitriolicBestBuds spend more time together]].

* SignatureScene: A popularity poll ran for the best scenes in the franchise, with the results featured in the mobile game Imaginary Fest's secondary anniversary. The winning scene was Touma's PreAsskickingOneLiner "Grit your teeth, strongest" as he punches out the top esper Accelerator to put an end to his massacre of the Sisters.

* NeverLiveItDown: [[spoiler:No matter how much good he does or how many heroic acts he does, some fans still hate and can never forgive Accelerator for the terrible things that he's done, especially what he did to the Sister Clones before his HeelFaceTurn.]]

* SeasonalRot: Fans of the series had been clamoring for a third season of the anime for almost a decade, and in 2018, [[CueTheFlyingPigs it finally premiered]], then became an instant example of BeCarefulWhatYouWishFor among the fandom, since it was an extremely CompressedAdaptation that at some points didn't even make any sense to those who hadn't already read the novels. The downgrade in art quality despite being from the same studio didn't help its reception either.

* AlternativeCharacterInterpretation:
** Accelerator: [[spoiler:A young man who's trying to redeem himself for the terrible things he has done while trying to avoid turning back to his past self or a sadistic heartless monster who hasn't changed his ways and enjoys being a powerful killer?]]
** Aleister: Is he nothing more than a giant {{jerkass}} who loves nothing more than [[GambitPileup piling up one evil scheme after another]]? Or a WellIntentionedExtremist with ulterior motives? His actions would suggest the former, while his backstory leans in the direction of the latter. Revelations in the later light novels suggest that he is indeed a WellIntentionedExtremist, though one who doesn't deny his own selfish motives.

** Not to be left out, the third main character Shiage Hamazura. There are those who like him for being a true Level 0 unlike Touma [[BadassNormal who still kicks ass with nothing but wits, guns, and luck]] [[spoiler:(even defeating his own Level 5 Mugino in an epic fashion)]], which makes him something of an AudienceSurrogate like [[Manga/ACertainScientificRailgun Saten]], and they think his relationship with Rikou is very sweet while being amused by his ButtMonkey status in ITEM before (slowly) gaining more respect from them. There's also the fact [[spoiler:he's the first person to truly inconvenience Aleister]]. On the other hand, there are those who dislike him because he's not that attractive compared to Touma or [[spoiler:Accelerator]], he's a Level 0 with no cool powers unlike the rest of the male characters of the series yet manages to pull out wins against incredibly dangerous foes, finding his servant boy and ButtMonkey status for Team ITEM annoying rather than funny, and [[spoiler:he defeated fan favorite villain [[EvilIsSexy Mugino]] and [[{{Yandere}} scarred her]], which brought him a lot of hate from her fans!]]

* DiagnosedByTheAudience: While it doesn't usually get brought up in the series, it's clear that Touma's loose morality and certain personality quirks, along with a number of other possible cases [[spoiler:after his ordeal against Othinus]] are enough for readers to take note of.

** [[{{Main/Teleportation}} Kuroko Shirai hanging out with her friends and immediately excuses herself by using teleportation]] to glomp Misaka.

** Thanks to Mikoto in Episode 10 of Railgun, fans have now call Touma's doctor, Dr Gekota! (At least it beats calling him Frog Face but it still doesn't beats his title [[spoiler: [[AwesomeMcCoolname Heaven Canceller.]]]])

* CompleteMonster: [[HolierThanThou Terra of the Left]] is the most violent, [[EgocentricallyReligious self-righteous member]] of God's Right Seat. Using an ancient magical artifact to manipulate the people of a French town, Terra sends them after Touma Kamijou and cares nothing when the riot causes the brainwashed citizens to be attacked by an Academy City attack force. Revealing his intent to launch a full-scale attack on Japan, Terra [[PoliticallyIncorrectVillain shows disdain for all non-Catholic lives]] and shamelessly admits to murdering "[[KnightTemplar heathen]]" men, women and [[WouldHurtAChild children]] to perfect his magic.

** In a sense, Kuroko x Awaki pairing is also this, since they fight each other twice in one arc.

** Kakine Teitoku a.k.a. Dark Matter and Uiharu. Yes. That Uiharu. [[WouldHitAGirl Despite their first interaction with each other shows Kakine torturing Uiharu]], that don't stop certain amount of fans from wearing their ShippingGoggles.

** Kakine Teitoku a.k.a. Dark Matter and Uiharu Kazari. Yes. That Uiharu. [[WouldHitAGirl Despite their first interaction with each other is a]] bone-chilling one, that didn't stop certain amount of fans from wearing their ShippingGoggles.

* TheChrisCarterEffect: A frequent phenomenon among fans. The [[LightNovel/ACertainMagicalIndex series]] has by now introduced [[LoadsAndLoadsOfCharacters so many plot-relevant characters]] with [[AlwaysABiggerFish even more potent powers]] with their own storylines that many people have trouble keeping up even with character charts. Combine this with the fact that the revelations about Imagine Breaker and the way Espers work have been minimal so far (and many other less important questions haven't been answered either, but [[KudzuPlot rather just raise new questions]]) and that CharacterDevelopment has been all but non-existent for the majority of characters as of late (including main character Touma), and that the staff seems to be more interested in working on the spin-offs rather than the main story, and you have a giant chaos that has little potential of eventually wrapping itself up completely.

* {{Fanon}}: [[spoiler:Fans have speculated that the Amakusa Catholic girl that Touma fought and saved from a fall in Volume 7 may be Itsuwa, the Amakusa warrior who was first introduced in Volume 11 which may explain why she has a crush on Touma in the first place. However, the 2nd season anime had it {{Jossed}} as it wasn't Itsuwa that Touma saved but another girl.]]

* LesYay: Mikoto and Kuroko, though mostly on Kuroko's end. Mikoto's more annoyed at it than anything, but on occasion (when Kuroko isn't being obsessive about it), she does return it.

* MoralEventHorizon:
** The researchers involved in both events under the ForScience entry above cross this line in a ''big'' way.
** Then there's the [[spoiler: [[AlwaysSecondBest #2]] [[SuperpowerLottery Level 5]] [[ArrogantKungFuGuy Teitoku Kakine]]. He's ObviouslyEvil from the get go, but he still manages to be [[AffablyEvil personable]] enough that you aren't quite sure what you think of him, especially since most of his darker actions to this point have been against people [[BlackAndGrayMorality who aren't exactly paragons of justice even on their best days]]. That is, of course, until he '''beats up [[TheCutie Uiharu]]''', earning him the hatred and rage of the majority of fans. It could have been worse though, it didn't {{break|TheCutie}} or [[KillTheCutie kill her]]]].

* CriticalResearchFailure: The reason why Stiyl looks so old despite supposedly only 14 was because of a miscommunication between the artist and author: Touma and Stiyl's first confrontation was supposed be something of an [[MagicVersusScience Old vs New]] (which the artist took literally to mean "old man vs. young boy"), completely missing the note that said Stiyl was only 14.

** As a way of [[HandWave hand-waving]] the aforementioned CriticalResearchFailure, a somewhat popular interpretation is that Stiyl [[{{Glamour}} uses magic to appear older]].

* FunnyAneurysmMoment:

* HarsherInHindsight:

** Anna Sprengel seems to be doing her level best to earn this title. Selfish, vindictive and cruel, she's repeatedly shown a fondness for sadistically (and sometimes fatally) manipulating people [[ForTheEvulz for her own apparent amusement]]. Perhaps her worst act (so far) is during Operation Handcuffs, where she [[spoiler:uses magic to manipulate the probabilities into the worst possible outcomes, leaving hundreds or more dead (in various horrible ways) and many more permanently traumatized.]] And then she goes out of her way to mock [[spoiler:Accelerator]] about it.

** Mikoto and Misaki, carrying over from [[Manga/ACertainScientificRailgun the spin-off it got started in.]]

* SeasonalRot: Fans of the series had been clamoring for a third season of the anime for almost a decade, and in 2018, [[CueTheFlyingPigs it finally premiered]], then became an instant example of BeCarefulWhatYouWishFor among the fandom, since it was an extremely CompressedAdaptation that at some points didn't even make any sense to those who hadn't already read the novels.

* Fre/nda, a mocking nickname used by both Western and Eastern fandoms [[spoiler:after she gets [[HalfTheManHeUsedToBe bifurcated]] by Mugino.]]

%%** Kuroko is dead.
%%** There's a 50/50 chance of anything to happen [[spoiler: from the {{Mundane|MadeAwesome}} to the [[SugarWiki/MomentOfAwesome Awesome]]]].

** It's also fairly common fanon that Lola Stuart is Index's mother, especially since the two are specifically drawn to resemble each other. This also adds an extra KickTheDog element to Lola's treatment of Index if you buy that theory.[[spoiler:This is disproven by the revelation that Lola is Aleister Crowley's daughter.]]