This author has written a series of Touma/Othinus pairing fics that continue from New Testament Vol 9's ending, starting with The Smile Of A Single Girl. Each one is hilarious and heartwarming as the couple learns to make their relationship work. Has also written one not connected to the series called Failure: Locked.
Synopsis: Sogiita Gunha. The 7th of 7. The strongest Gemstone out of the 50 around the world. A series of magical and scientific events occur around the #7. Each side trying to discover what kind of power he wields and use it for their own benefit. Will Gunha and his friends live though these events? (Takes place after NT 7!) An action/Adventure story with bits of humor.
Comment(s): If you need some GUTS in your life, this is the story for you! Sogiita is portrayed perfectly and his adventures inside Academy City are worth reading! Though I would avoid this if your not into OC's, as they drive the story along with Gunha.
Synopsis: A Railgun centric fic. Kuroko starts at Tokiwadai and meets a certain someone. However their relationship is off to a rocky start.
Pairings: None... Though we can be sure Kuroko will be complaining about that at the conclusion of the story.
Comments: Cun writes very much Original Flavour and his characterization is spot on. If you can't get enough the originals mixture of Comedy, Mystery and heartwarming friendship, this is very much recommended. Note that this isn't just a Slice of Life - different seemingly disconnected incidents are slowly coming together into a bigger plot.
Seconded by moberemk; this is easily the best Index story on FF.net right now, with frighteningly good characterization and writing. Even Kuroko becomes not only bearable but interesting, and that's saying something.
Synopsis: Feeling grateful towards Touma, Index and Mikoto put aside their differences to organize a Christmas party for him. Takes some slight Broad Strokes from canon.
Pairings: ToumaxMikoto or ToumaxIndex? Take your pick, or maybe both.
Comments: An interesting story that otherwise when necessary stays within canon. Almost every named character is at least referenced and includes a small cross-over with Maid-Sama!. The author even seems pretty Trope Savvy, throwing in a joke or two about Actor Allusion. All the while Tsuchimikado is distracting Touma with a search for the very enemy of Christmas himherself...
Synopsis: It's Valentines Day in Academy City. Mikoto feels insecure with her femininity after recieving so many chocolates from girls. Touma, of course, receives more chocolates from girls than anyone else in his school. But an Unknown Rival in another class is sick of Touma's popularity and challenges him to a duel for all his chocolates. But not just any duel, a Badminton duel. At the same time, the boys of GROUP follow a suspicious acting Awaki and end up more involved in her love life than they ever wanted.
Pairings: Some light ToumaxMikoto
Comments: A fun adventure that's hilarious as it is thrilling. Top scenes include Mikoto's faulty logic for getting Touma to fall for her, and the GROUP boy's heartwarming attempts to protect Awaki.
Synopsis: An AU version where Index never fell onto Touma's balcony, Accelerator never killed a single clone and never even got the chance, and Project RADIO NOISE, the plan to create an army of Black Ops clone soldiers based on Mikoto's DNA was never canceled. In fact, it took the form of an shadow organization dedicated to cleaning the streets of Academy City of its bad elements. Kamijo Touma is dragged into this darkside of Academy City after he witnesses the Sisters cleaning up an operation. Hunted by the Sisters, Touma is determined to get to the bottom of what he saw. He soon encounters and becomes entangled with the newly formed GROUP, who have the mission of destroying RADIO NOISE and killing its leader, Last Order.
Comments: This is what happens if you take the Index-verse and turn the grim darkness up to 11. Violent deaths are common and the fic fully explores the grittiness of Academy City's darkside. Touma is different as well, having all his memories, being slightly more cowardly, and no idea what the power he possesses is capable of.
Synopsis: After a cataclysmic event that unleashed the most horrible, brutal battle in the history of Academy City, we follow a day in the limelight of the only person on the entire city and maybe even the civilized world who's oblivious to the evil that happened the night before.
Pairings: A little ToumaxHimegami, but just barely.
Comments: A hilarious one-shot about a character that needs more love on the fandom; with a few romantic moments, everyone in character and even a couple of guest stars at the end.
Synopsis: Follow Misaka-11111 as she chronicles her ever-continuing observations of the world around her in her secret diary. In analogue form, of course, for more secrecy.
Comments: An original comedy fic that captures the point of view of a MISAKA Sister perfectly, complete with excellent humor revolving around her train of thought and how she adjusts to a world without "the Accelerator."
Synopsis: Proximity Trace, the ability to mimic compatible Personal Realities. Just what is the truth behind Ryusuke's past? What secrets does Academy City have to hide? Touma X Harem, OC X MISAKA 19090.
Pairings: Touma/Harem OC/Misaka 19090 (although neither show up in the story, and are being saved for the sequel
Comments: The story follows the character Ryusuke as he acts as a side character in the canon story arcs of Railgun and Index, all the while trying to discover what happened in his Dark and Troubled Past. It is a legitimately good OC based story. It manages to have an OC that is not a Mary Sue, mainly by having him get his ass kicked a lot. The power of the main character is interesting, making him like Peter Petrelli except that the powers he gathers are weaker when he uses them than when their original owner does. The sequel A Certain Angelic Finality can be found Here.
Synopsis: Accelerator and the Railgun. Two level 5's that have been subjected to the same rumour: they have been defeated by a Level 0. But who is this mysterious esper? This is the numerous investigations made by characters in the To Aru universe into this Level 0. People who don't know him will learn the truth and those who do know him will catch a glimpse into his life. Will have action.
Synopsis: A 'For Want of a Nail' type story, this basically retells the story of Railgun and Index with Touma and Misaka having been childhood friends.
Comments: Hasn't gotten very far in- the story just got part the Graviton Bomber plot, and apart from a bit of Foreshadowing, Index hasn't shown up yet. That said, I find it a fun read so far. NOTE: It does need to be mentioned that this fic takes a significantly... darker... approach to Touma's backstory, which may turn some people off.
It's gotten to the Index arc, which is running simultaneously to the Level Upper plot. Touma's backstory is a nice touch; it's darker than the backstory in the original, but arguably gives Touma (and even Mikoto by extension) a little more depth. Mikoto is a little bit more interesting as well, now that she's not relegated to zapping Touma whenever she sees him. All in all, a great read so far. Nothing too major has changed in the plot, except that SCHOOL is now involved in Level Upper, Mikoto and Kanzaki fight while Touma fights Stiyl, and there's boatloads of Touma/Saten Ship Tease.
Unfortunately, this fic appears to be dead since it has not been updated since September, 2011.
However, despite the fanfiction being considered dead, it spawned an ongoing spin-off known as Of Science And Magics The Side Stories which was authorized by Stormwolfex prior to his departure from fanfiction.
Synopsis: A tale of a battle between two great forces and those who get swept up in it. As the two level 5s face each other a conspiracy is revealed and a romance blooms, but what does fate hold in store for The Ace, The Queen, and The Two of Hearts?
Synopsis: The 'Queen of Tokiwadai', Shokuhou Misaki, meets Kamijou Touma. Mikoto gets jealous and things get worse/better from there, depending on one's viewpoint. Expect trouble, or should I say Misfortune?
Pairing(s): There is some ToumaxMisaka, and there might later on be some ToumaxMisaki
Synopsis: The bro adventures of bros doing bro things.
Pairings: None beyond the usual affections you'd see in the usual series.
Comments: Arguably the funniest fanfic in the fandom, and the best I've seen yet in the series from a pure humor standpoint. That it focuses less on pairings and more on the shenanigans the males in the series get into certainly helps its case as far as making sure the humor is rarely deviated from. Always good for a laugh if only because of the outrageous situations alone. Which someone was kind enough to help put to an actual image in regards to the prologue anyway◊.
Synopsis: Kamijou must join a sports event in Tokiwadai for merits. What happens if he ended up fighting all the level 5's?
Pairings: The usual Unwanted Harem hijinks Touma, Accelerator, and Shiage experience.
Comments: Insanely action-packed and hilarious. Seems to be set during New Testament. Touma's harem just grows and grows. Lots of surprises and Wham Episodes including the return of Teitoku Kakine, the person Touma used to be before he lost his memories getting his own body, One-Eyed Othinus turning Sherry Cromwell's long-lost friend Ellis into an undead servant, Touma fighting Misaki and the mysterious 6th level 5, ect.
Synopsis: In a bid to safe Last Order's life, Accelerator accidentally brings himself, the other level 5s, Touma, Shiage Hamazura, and Rikou Takitsubou to an alternate universe where everything, even the animals are different. Given a mission by a certain, mysterious goddess, the nine individuals will deal with different lives, and perhaps even love.
Comments: This is exactly what the summary described. To explain this story, this is an Alternate Universe story involving the main protagonist of the Raildex universe as an overpowered character. Yet, the way that the writer depicts OP Touma isn’t that bad story-wise; in fact, it just makes the plot a lot more Badass than usual.
Synopsis: "When the man turned to look, he saw from the rock, a young woman bathing in the waters. She had the height of a girl, but all the qualities of a woman..."-Follow the secret history of Kihara Kagun, as he tries to search for magic, despite the cold land of the North, evil winds, vile wolves, dark drakes, and a haughty Dvergr, as he realizes its true and terrific nature.
Synopsis: Kamijou Touma has never been the luckiest person in the world; but due to that lack of good fortune he isn't ignorant to those in need. But a simple impulsive act results in him meeting someone who thrives in a darker world hidden beneath the surface. Now at the crossroads: will he trek into the unknown to save that girl or be devoured by the beasts that lurk within the darkness?
Comments: An alternate universe where Mugino is Touma's self-proclaimed rival instead of Mikoto. Author is very wordy though. Has a fan-made illustration.
Recommended by spacemonkey37, Aleph, mysterius, universalperson
Synopsis: AU/Rewrite. In a city where science has made the impossible mundane, a young man meets a very strange girl, who speaks to him of things yet stranger. Meanwhile, four friends stumble into a conspiracy that threatens to overturn everything they thought they knew about their home.
Synopsis: Set between New Testament 7 and 8. Beetle 05, aka the new Teitoku Kakine, settles into his new role as Academy City's newest hero.
Comments: It starts out very funny, then the plot picks up in chapter 4, where Saten gets strange dreams, gets a massive spike in AIM during a System Scan, and Gunhaseriously refers to her as the 8th Level 5 before forgetting what he said.
Synopsis: Something is happening to the life of a certain Level 0 and for some reason he starts to have luck with the women. Obviously something is terribly wrong especially with disasters after disasters start to occur around him both of the magic and science variety. Some force is messing with Touma's life. Love triangles or Dodecahedron. Secrets will be revealed. Touma X Harem.
Comments: As usual, Touma is incredibly badass and a hilarious harem hero.
Synopsis: In an universe parallel to the main To Aru continuity, Number Two Level 5 esper Accelerator (and Level 0 Hamazura) is trying to stop his world from collapsing due to distortions caused by a "missing variable" (implied to be Touma, or just the Imagine Breaker) critical to the universe's cohesion. And it's Accelerator's job to delay the distortions until the mysterious "Keeper" and her organization fix the problem.
Comments: An intriguing read, and definitely a nice change of pace from all the other To Aru fics out there. Not a dark fic, since there are quite humourous bits thrown here and there, but you get the feeling that something is quite wrong with everything. There is also a quite explicit...er, heated interlude, but it flows naturally in the narration and not just lemon for lemon. The OOC is also intentional, since it's literally a parallel universe. Also released a few days after New Testament volume 8, it fits nicely with canon considering what happens in New Testament 9...
Synopsis: Following his fight against the alchemist Aureolus Izzard, during which his right arm was cut off, Kamijou Touma wakes up in a certain hospital to find that his body now emits an AIM Field. He is now an esper. A fact that leads Touma to reach another, troubling conclusion: he has inexplicably lost his Imagine Breaker.
Comments: A solid premise, well handled by its author. The idea of a Touma without Imagine Breaker is interesting, what with him having to deal with a protagonist's problems armed with only a support character's power. The fact that the premise also hasn't been overused (yet anyway) is probably also a plus. Touma also finds out that it's not easy talking and acting all righteous when you don't have the power to back it up, and that not everyone's problem can be solved by taking all the heat himself and hoping for the best. Also notable is the Invisible Thing making itself known to Touma.
Synopsis: Accelerator finds a drunk Worst and tries to take her home. But, so many people keep getting in the way, and funny crap keep happening. Characters drop hints on Accelerator on what is Worst to him.
Pairings: Accelerator x Worst
Comments: Very funny, it is slight AU, but it keep the theme and not really any OOC. Freakin funny ending, and cute moments. And a very ax crazyyandere Worst gets jealous of Awaki being with Accelerator.
Synopsis: Accelerator and Vento of the Front wake up and find that they are now married!
Comments: Absolutely hilarious. These two are total potty-mouths, but it is heartwarming how they learn to make the relationship work. Plus, nothing beats Fiamma of the Right using the Jedi Mind Trick!
Synopsis: From Fanfiction.net summary: "Hey..." Mikoto stared up into the clouds she laid on the ground, the grass brushing against her arms. She closed her eyes as a soft sigh escaped her, "Is it possible to fall in love with someone you always believed to only be a friend?"
Tags: Future fic, AU, Yuri
Comments: A nice fic about a slighty older and more mature Mikoto trying to understand her feelings for her best friend.
Synopsis: The Electric princess has fallen into a deep sleep from the curse of a witch, if only a wandering prince would kiss her awake. A humorous take on a classic fairy tale using the cast of TMnI. - from Baka-Updates
Warnings: Has some sexy but is SFW (think To Love-Ru). The translators mainly translate Hentai, so don't go exploring their other stuff if that's not your kind of thing.
Comments: This is simply hilarious, and I think quite in character.
Synopsis: Sequel to Last Order In Your Eyes!. Once again the hero must brave the kitchen to expose his culinary skills; shamed by his previous disappointment he'll have to show his true potential as a chef, or this meal really will be... *puts on military goggles*... His Last Order. - from Baka-Updates
Pairings: Friendship AcceleratorXLast Order
Warnings: The translators mainly translate Hentai, so don't go exploring their other stuff if that's not your kind of thing.
Synopsis: A Puella Magi Madoka Magica/Index crossover fancomic, by Kosshii-san of Pixiv. This is Touma coming to Mami's rescue... TWICE. Well, the first was when he rescued her from her in-series Episode 3 end, and that's drawn before this one.
Comments: This fancomic shows why you must not mess with anyone that Touma has recognized as a friend. Not even being in numbers can save you anymore. Also Codename Strike's personal favorite crossover (well, just give him any remotely interesting Madoka/Index crossover and you're in for a treat.)
Comartemis: Seconded. The artist has a couple of other comics as well, one of which features Touma punching out Ocktavia and saving Sayaka.
Da Random User: Suspension of disbelief definitely required for this one regarding some plot material. That being said, don't get too hung up on the plot because watching Touma beat the snot out of a bunch of school-age punks is still intensely satisfying.
Rakuro Kamigama: Although the quality might not be up to some people's expectations and the story is a bit short and simple, the crossover doujin is well made and really confirms that you DO NOT mess with Touma and his friends. Nothing will save you from Tou Man punch. On the other hand, the other doujin crossover (visual improvement shown) that shows the climax of the battle shows Accelerator and Touma beating Kyubey. As expected, it was intensely satisfying
Recommended by Codename Strike. Well, d'uh, it's more or less a continuation from before, so why not?
Synopsis: Takes on during Homura's lone and hopeless battle against the strongest Witch, Walpurgisnacht. Just when all hope seems lost, another Strongest appears...
Comments: "Were you expecting Kamijou-san? TOO BAD! IT'S THE MOTHERFUCKING ACCELERATOR!!!", as per the (not-so, maybe exaggerated by a bit) exact words of Kosshii-san on his comment for this one. This is still ongoing as the Danbooru pool indicates two parts of the story. Also, Codename Strike just can't help but notice what a nice match the artist decided on - remember, Strongest versus Strongest?
Part 1: A Yu-Gi-Oh!/Index fic staring Motor-mouth, a character from PokeRescue18's other fic Crisis on Two PokeWorlds!. Motor-mouth is challenged to a duel by a strange magician. But whenever Motor-mouth summons a monster, a character from A Certain Magical Index appears wearing the monster's clothes instead!
Part 2: Sequel to A Certain Duelist's Dream. Motor-mouth is challenged to a duel by his Evil Knockoff, Darth Motor. Like before, whenever Motor-mouth summons a monster, a character from A Certain Magical Index appears instead. But with Darth Motor's Nordic deck, soon he's summoning members of GREMLIN!
Part 3: This is the Spiritual Sequel to A Certain Duelist's Dream 2: The Nightmare of Gremlin. In an alternate universe, Duel Monsters is introduced to Academy City. What sorts of impacts will this card game have on its citizens, especially that of a certain unlucky boy and his friends?
Part 1: Extremely hilarious, and reminiscent of the Yu-Gi-Oh episode when Bakura trapped everyone in their favorite cards. The duel is well done, using real-world rules. Plus, Accelerator becomes a Butt Monkey because his card keeps getting revived and sent back to the graveyard, and Kakine Teitoku gets destroyed as soon as he's summoned!
Part 2: This sequel fanfic has become Darker and Edgier, but it didn't lose much of its hilarity, especially with the character summons. Once again, the duel is well done, using real-world rules. At the climax, Motor-mouth was too late to realize that Darth was being a Manipulative Bastard. His field was utterly devastated, and Darth Motor achieves a Near Villain Victory, briefly inducing Motor-mouth in his Heroic BSOD. In the next turn, Motor-mouth managed to recover, and ultimately synchro summons Shooting Quasar Dragon, which is portrayed by none other than Touma Kamijou himself! And there's the Stinger at the very end, setting up a Sequel Hook.
Synopsis: Crossover with Haruhi Suzumiya. Aleister Crowley and the Magic Side learn of Haruhi's Reality Warper powers. He is convinced she is a Level 6 esper, while they are convinced she is God, except for the Roman Catholic Church, who think she is a dangerous heretic. The SOS Brigade and the Kamijou Faction must join forces to keep her safe from their schemes while at the same time oblivious to the supernatural. Has its own page.
Pairings: ToumaxHarem though mostly with Mikoto, KyonxHaruhi, KyonxMugino, ShiagexRikou
Comments: It's very funny, has awesome fight scenes, and at the same time keeps everyone in character and blends the two shows so well it might as well be canon.
Synopsis: Set in the world of Pokémon. Famous for having every Pokedex and Pokeball fall apart on him, Kamijou Touma is lost in the Viridian Forest. Chased by a swarm of Beedrills, he's saved by a cute girl... who thinks she's a Pikachu! With a certain magical Pokedex, a growing team of Pokemon girls, and a strange power in his right hand - Kamijou's journey as a Level Zero Pokemon trainer begins.
Synopsis: Othinus throws our main character into Gensokyo. Well, at least the locals fight fair instead of using hitscan explosions. What defines a main character? The poverty, the free loaders, the black hair or the name with religious connotations? The power to float above reality or the power to bring down to reality? A story of self doubt, random references and multiple retries.