* 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 [[spoiler: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 back story leans in the direction of the latter.
* BaseBreaker: There are three separate camps for viewing [[spoiler:Accelerator]]. One, the people who focus on his [[spoiler:lethal methods who makes of him a bloody monster]]. Two, the people who focus on him [[spoiler:trying hard to redeem himself even if that means throwing away his life.]] Three, people who [[spoiler: [[DracoInLeatherPants liked him from the start, and don't have to forgive him for anything.]]]]
* BigLippedAlligatorMoment: Index-tan Episode 1 for the second season: Each of Saten's appearances are this.
* ContemptibleCover: The cover of New Testament 9, widely considered one of the best volumes in the series, has nothing but a picture of Othinus wearing the equivalent of ChainmailBikini.
* 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.
* EnsembleDarkhorse: [[{{Tsundere}} Mikoto]], [[IceQueen Kaori]], [[PsychoLesbian Kuroko]] and [[spoiler:[[ShyBlueHairedGirl Itsuwa]]]] are very popular with the fans, [[BreakoutCharacter ultimately spawning]] [[Manga/ACertainScientificRailgun a franchise of their own]].
** [[spoiler:[[FourGirlEnsemble Team ITEM and The New Light]]]] are very popular among fans despite both groups being [[spoiler:the antagonists]].
** Now with the second season of Index, Fukiyose Seiri has become very popular with fans on her debut in Episode 8.
* {{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.]]
** It's also fairly common fanon that Laura Stuart is Index's mother, especially since the two are specifically drawn to resemble each other. This also adds an extra KickTheDog element to Laura's treatment of Index if you buy that theory.
** Fans have theorized for years that Aogami Pierce is the sixth level five, by this point they would be furious if it turned out it wasn't him.
* FanPreferredCouple: Majority of the fans ship Touma with Misaka. Though after NT 9, it seems to have shifted to Touma with Othinus.
* FoeYayShipping: Touma and pretty much all of his female opponents.
* FunnyAneurysmMoment: Index-tan Episode 2: Himegami is asked what her wish for the second season is. Her response? "Um, I won't ask for my episode, but I just want to be treated [[RunningGag more-]]". Guess what happens in her first lengthy appearance in season 2? [[spoiler:She gets [[BloodierAndGorier filleted]] by Oriana Thomson because she thought that Himegami was an agent of Necessarius due to the Celtic cross around her neck.]]
* GodModeSue: Accelerator. He can modify and redirect vector values of anything by touch, bend the laws of physics to his will, understand unknown or strange laws hitherto unknown to him and making use of it, can survive a nuclear missile, its shockwave, heat and radiation, and it's subconscious, meaning that it is active all the time. The only things that can counter it are the Imagine Breaker and attacks that are built upon laws or vectors unknown to him.
** This is only partially true: [[spoiler: As of the second to last arc of season 2, we know that even non-espers can damage Accelerator, as long as they utilize special properties of how his power was trained/developed in the first place (as seen through Kihara Amata). Not to mention that Accelerator experiences "circumstances" that make him lose his powers, and the only way he can use a weakened version of them after this incident is through outside assistance.]]
* HarsherInHindsight: Academy City's Power Curriculum Program. In theory anyone undergoing this program can become an esper yet there are still people who have yet to gain powers and even those who did never go a higher level which suggest the program has some problems. [[spoiler:However Vol. 22 reveals the program is secretly being undermined by the Higher Ups of Academy City who decide who can and cannot gain esper powers and/or go a higher level based on the type of the powers that person has. This revelation makes it much worse once you realize Level 0's like Saten, the Skill Outs gangs and low level espers like the Level Upper users, who work hard to gain powers/higher levels but never can because their training is being sabotaged as the Higher Ups see no point of helping anyone who doesn't have the powers they want. That's right, the city is responsible of destroying the dreams of many students and leading them into path of cynicism and crime!]]
** All intentional; while Mikoto claims in SS: Liberal Arts City that Academy City has no intentions of taking the world via military force, the revelation via Chapter 22 suggests otherwise. Why else would you try to make an army of level 5s or an "interceptor" aircraft that has the ability to fly halfway around the world and level a city single-handedly? Basically, the reason why the corporate crooks of AC haven't bothered leveling the level zeros of their population isn't just because they don't want to, its because they need cannon fodder; they needed a group of disgruntled individuals who they knew would resort to violence in order to defend themselves against those termed and rewarded for being genetically superior, so that they might label that group as people on whom it is okay to use your powers, people whom it is okay to murder, because no one will care about them due to their collective reputation.
* HolyShitQuotient: A large portion of the series, but the entirety of Volume 22 and New Testament Volume 9 are probably the biggest. Especially NT Volume 9.
** Every new book (except arc finales like Volume 22) usually makes the HolyShitQuotient go way higher than the previous book. NT Volume 10 takes this to an extreme arguably outdoing even NT volume 9 with its insanity especially in its epilogue.
* IronWoobie: Touma gets his ass kicked on a regular basis, and even the fights he wins tend to end with him in the hospital. There's no real explanation for why he puts himself through such misery, especially considering he has his own [[BlessedWithSuck inherent bad luck]] to deal with. And yet he claims to be ''happy'' with way he lived his life...
** But he always does win in the end, and women fall like flies to his two-dimensional Shonen Protagonist hero speeches. What's not to be happy about?
** The novels explain all of this in detail... eventually. Volume 22 summarizes it quite nicely, though NT volume 9 best outlines his "real motivations." [[spoiler: NT volume 9 partially trolls and explains that Touma doesn't really believe half of the "hero speeches" that he gives to villains. He just does this to briefly get through to people who have temporarily gone crazy as a result of experiencing severe loss/tragedy in their lives. As of NT volume 9, he has a higher moral ground and it is actually justified because of what he went through...]]
* JerkSue: Misaka is smug, rude, violent, and a generally unpleasant person... and is loved by practically every character, and got [[Manga/ACertainScientificRailgun her own spinoff.]]
* LauncherOfAThousandShips: [[HaremGenre And how...]]
* LesYay: Misaka and Kuroko, and how!
** Misaka WORST and Umidori.
** Kuroko admits that she would love to have both Misaka and at least 1,000 of the clones to herself.
** Kanzaki Kaori and Index, more so in the first arc and in their past.
** Index and Kazakiri Hyouka. Hyouka notes that Index acting {{Tsundere}} for Touma is a sign that she loves him. Then, much to Hyouka's surprise, Index acts '''the exact same way''' towards her.
** Kanzaki and Orsola.
** With some FoeYayShipping, Oriana towards Himegami and Fukiyose.
** New Light, particularly Bayloupe and Lessar, though Floris and Lancis aren't exactly innocent either. The group seems the be well aware of their apparently abnormal closeness too.
---> '''Floris:''' "Hey, you two lesbians who look like you’re from some erotic novel or something." [[note]]Said when Bayloupe and Lessar were in a compromising position in the back seat of a car.[[/note]]
---> '''Lessar:''' "Floris! Lancis!! Quit awakening strange new tendencies and wake up! We need to use this room!!" [[note]]Said when Lessar found the two sleeping in the same bed when she needed to have a chat with Mikoto. Apparently Floris just likes to crawl into other peoples beds when sleepy.[[/note]]
** At this point, To Aru needs its own page.
* [[MagnificentBastard Magnificent Archbishop]]: [[spoiler:Laura Stuart]].
* MemeticMutation:
** Kuroko is dead.
** To Aru Majutsu [[spoiler:[[ArtifactTitle N]][[OutOfFocus O]]]] Index.
** There's a 50/50 chance of anything to happen [[spoiler: from the [[MundaneMadeAwesome Mundane]] to the [[SugarWiki/AwesomeMoments Awesome]].]]
** [[http://1-media-cdn.foolz.us/ffuuka/board/a/image/1333/52/1333528123603.jpg GENDER EQUALITY!]] The fact that the male protagonists have no problem beating up female opponents seems to resonate with the fans when so many other series take WouldntHitAGirl so seriously.
** Creator/GeorgeRRMartin is helping write the series. [[labelnote:Explanation]]NT Vol 7's incredibly dark storyline, which includes characters being told that Maika Tsuchimikado had died offscreen ([[spoiler:it was a false alarm]]), was similar to Literature/ASongOfIceAndFire's AnyoneCanDie style.[[/labelnote]]
** Maid spin, maid spin, maid spin...
** '''[[EvilIsSexy Hot]]'''[[HotWitch hinus]]
** {{OTP}} [[labelnote:Explanation]]Othinus Touma Pairing[[/labelnote]]
* MemeticSexGod: Everybody loves Misaka Mikoto.
** Everybody loves Touma.
* {{Moe}}: Several characters count.
** Special mention goes to Komoe-sensei, which is even in her name. She's also not above invoking this trope in order to guilt her students into doing things.
** Quite a few of the Sisters, but 19090 stands out. She's a minor side character, but in her first appearance (when the four Sisters still in Academy City were getting sized for their winter uniforms), the others discovered that she wasn't quite as identical as she was supposed to be, due to reading girly magazines and dieting. She runs away tearfully, while her Sisters hunt her down ruthlessly in an attempt to measure her more precisely and force her to fix her eating habits.
* MoralEventHorizon:
** The researchers involved in both events under the ForScience entry above cross this line in a ''big'' way. [[spoiler:Accelerator also crossed the line before he's even ''seen''; however, he seems to be trying to come back from it. [[NeverLiveItDown If you can forgive him...]]]]
** 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. That is, of course, until he '''beats up [[{{TheCutie}} Uiharu]]''', earning him the hatred and rage of the [[{{BaseBreaker}} majority of fans]]. It could have been worse though, it didn't [[{{BreakTheCutie}} break]] or [[{{KillTheCutie}} kill her]]]].
* MostWonderfulSound:
** The noise Imagine Breaker makes when it negates something.
** The sound effect of Accelerator's AttackReflector.
* {{Narm}}: Apparently, Accelerator can state-change air into plasma by making ridiculous noises with his mouth, though the ridiculous noises are another form of his evil laugh. This is also a case of FormulaicMagic, those noises he was making were Accelerator performing the calculations necessary to use his Vector powers at ''high speeds.''
* 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.]]
* TheScrappy: [[spoiler:Shiage Hamazura. There are some reasons some people dislike him. [[UnfortunateImplications He's not that attractive, he's a Level 0 with no cool powers unlike the rest of male characters of the series]], he's the servant boy and ButtMonkey for Team ITEM. It didn't help that he defeated the fan's favorite villain [[EvilIsSexy Mugino]] and [[{{Yandere}} scarred her]], which brought him a lot of hate from her fans!]]
* ShipToShipCombat: Which girl should be with Touma? '''Don't ask!''' because the moment you say so, you will get yourself in a nasty ShipToShipCombat between other fans over their favorite girl!
** Yet two of the biggest ShipToShipCombat by Japanese fans are the Mikoto x Touma fans and Kaori x Touma fans. These two fanbases are so big, the novel artist Kiyotaka Haimura knows it [[http://imageshack.us/a/img694/800/003dli.jpg and even drew about it!]]
** If you still remember Misaka Imouto, [[http://img132.imageshack.us/img132/9341/index1812.jpg this only adds more fuel to the fire...]]
** There's also a minor one with Touma and [[spoiler:Mitsuko]].
** Another small one is with [[AnythingThatMoves Aogami]] and Mitsuko.
** It's rather surprising how many fans are starting to pair up [[BigBad Fiamma]] and [[BadassPrincess Carissa]], considering their single canon interaction was an IShallTauntYou on Fiamma's part.
* {{Squick}}: How does the Roman Catholic Church counter Sheol Fear, a sound-based spell? [[spoiler: Whipping out fountain pens and gouging out their ears.]]
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