Based on the late Aleister Crowley. He was once the greatest magician in modern magic history, where more than half of all modern magicians are affected by this man's established theories, and two-fifths of them are direct followers of his ways. Aleister stretched the boundaries of sorcery farther than the advances made in the last few millennia alone and wrote many top-class spell books like The Book of the Law.

 His death in 1947 shocked many but it was not the last the world had heard of him. In reality, he faked his death to stop the obsessing fanatics following him and secretly went to Japan where he meet a doctor who he would later call Heaven Canceler. Years later, Aleister, Heaven Canceler, and several powerful individuals combined their resources and influences to create one of the most technologically advanced cities on Earth in western Tokyo, Academy City. By this time, rumors of Aleister still being alive led some mages to discover the truth. At first, they were happy to see that he was alive but were immediately shocked as that not only Aleister abandoned using magic but was more interested in the study and development of espers. 

To this day, only a few magicians know Aleister is still alive who are mostly the leaders of powerful magical organizations and their trusted followers, and those that do know him to view him with skepticism, curiosity on what he's doing, or outraged for abandoning magic and supporting science especially esper studies. Not making things any better is the fact Aleister was responsible for the creation of the truce between Science and Magic where neither side is allowed to interfere in each other affairs which have irked both sides. As the 13th Board of Director and General Director of Academy City, Aleister has the final say of the city affairs but usually leaves the city's welfare to the other members of the board. He resides within a tall, gray building called The Windowless building, known for not having any exterior windows where access to the building is a secret to a few. In there, Aleister's body which has now become younger lies inside a giant glass tube, supported by machines made by Heaven Canceler that extended his lifespan where he plots his mysterious plans.

Set in a city of scientifically advanced superhuman students, but in a world where magic is also real. Touma Kamijou&rsquo;s right hand, the Imagine Breaker, will negate all magic, psychic, or divine powers, but not his own bad luck. One day he finds a young girl hanging on his balcony railing. She turns out to be a nun from the Church of England, and her mind has been implanted with the Index-Librorum-Prohibitorum - all the magical texts the Church has removed from circulation.

Holds a 2nd Dan rank in Kendo. A veteran Japanese voice actor who has played characters in anime, drama CDs and video games. Apart from voice work, Toshihiko Seki sometimes does live-action drama stage work and is a member of 81 Produce.

__Non-anime roles:__
• Dottore (Genshin Impact)
• Chongyue (Arknights)

Index is still a fugitive, and many powerful magical organizations and individuals want to take her to use the books in her memory, eliminating her in the process. War between those organizations is also starting to emerge. Index can only rely on her friend Touma, who has always protected her, along with Misaka and other friends from the Academy. 
 
(Source: Anime News Network)

Science, magic, and a nun on the run! Kamijo and Index return just in time to celebrate A Certain Magical Index’s 10th anniversary with a brand-new season. After their deadly struggle against the Catholic Church and the pending war between magic and science, Kamijo must work harder to protect Index. But with tensions high all around, what new adventures await them in this next chapter?
 
(Source: Funimation)

Set in a city of not only scientifically advanced superhuman students, but in a world where magic is also real. Kamijyo Touma's right hand, the Imagine Breaker, will negate all magic, psychic, or divine powers, as well as his own luck. One day he finds a young girl hanging on his balcony railing. She turns out to be a nun from the Church of England, and her mind has been implanted with the Index Librorum Prohibitorum&mdash;all the magical texts the Church has removed from circulation. 
(Source: Wikipedia) 
Note: Includes 16 prologues, 18 epilogues, and 6 extras.

World War III is over. Touma disappears. Accelerator spends his days with Last Order and Misaka Worst. Shiage uses the secrets he gained in Russia as a bargaining chip.
 
But this peace doesn't last long as the Freshmen arrive...
 
(Source: Yen Press)
 
Note: Includes 21 prologues, 22 epilogues, and 2 extras.

In the movie's story, just before the completion of the Academy City space elevator "Endymion", the main characters Kamijou and Index encounter a level 0 girl named Arisa. The Magicians are after Arisa, and they attack Academy City. A female leader named Shattoaura leads a unit from Academy City against the attack. Kamijou and Index learn from Stiyl that Arisa is key to a brewing war between the sides of Magic and Science. 
(Source: Anime News Network)

The story is set in a world where supernatural powers exist through science, and magic exists through religion. 
In the story, Touma Kamijou is an ordinary high school boy with terrible academic scores and a power called Imagine Breaker. Imagine Breaker can defeat any other power, but it also undermines Kamijou's own good luck. His Imagine Breaker's immense strength is literally immeasurable, so hapless Kamijou is listed at the supernatural level of 0. He happens to meet a girl in white hanging off his window balcony. The girl says she is being chased by sorcerers, and Kamijou learns that the girl is a Church of England nun whose memories have been forcibly replaced by Index-Librorum-Prohibitorum &mdash; the 103,000 forbidden texts of the Church.

Science and magic exist side by side in this world. 
This is the peak of the science side with a curriculum for espers, Academy City. In this city where 80% of the population are students, the season has finally come when all residents are excited and fidgety! 
It's Christmas Eve. 
Amidst the city showing a cheerful hustle and bustle, ordinary boy who can’t keep up with school, Kamijou Touma, also doesn’t intend to miss this event! He was hard at work in his supplementary lessons... 
A backward glance from the default misfortune-prone bastard, the silver-haired sister freeloading in his dormitory, Index, in the heart pounding scene different from the usual, activates a new gluton skill!? While Kamijou tries to desperately stop that, Misaka Mikoto taken in by the Christmas Eve atmosphere appears before him.

Volume 1 (Set between volumes 13 and 14) 
A series of short stories set before the events of volume fourteen including how Team GROUP was formed. 
Volume 2 (Set between volumes 16 and 17) 
A series of short stories including two separate meetings between Touma's and Mikoto's parents, two tales involving two of the Level 5s of Academy City, and other funny stories involving some of the characters. 
(Source: Wikipedia) 
Note: Volume 1 contains a prologue and epilogue.

A doujinshi written and illustrated by Kiyotaka Haimura.

Toaru Kagaku no Railgun: Arts and Sciences City SS is a short story in Arts and Sciences City that takes place in the time period between September 3rd to 10th. Academy City has a exchange program with the rest of the world that allows some students to travel for this week to other places, and some students are allowed into Academy City during this time. 
Mikoto, Kuroko, Saten and Uiharu went to the Arts and Sciences City, made on a artificial island off the coast of California for a field trip. The Arts and Sciences City is known as a city that has cutting edge technology (in terms of the standards of the 'Outside' of Academy City - ie it is still far behind that of Academy City's), and is trying to take over Hollywood as the entertainment capital of the world. Stuntsmen and shows occur frequently at this city, and anything out of the ordinary is treated as another show. Due to the climate apart from sleeping everyone wears their swimsuits all the time. 
(Source: Toaru Majutsu no Index Wiki)