is a Japanese light novel series written by Kazuma Kamachi and illustrated by Kiyotaka Haimura, which has been published by ASCII Media Works under their Dengeki Bunko imprint since April 2004 in a total of three separate series. The first ran from April 2004 to October 2010, the second from March 2011 to July 2019, and the third from February 2020 to present.
The plot is set in a world where humans called espers possess supernatural abilities. The light novels focus on Toma Kamijo, a young high school student in Academy City with the ability to cancel other espers' powers, as he encounters an English nun named Index. His ability, which allows him to cancel other powers by touching them, and his relationship with Index prove dangerous to other sorcerers and espers who wanted to discover the secrets behind him and Index, as well as the city.
After being rejected for the Dengeki Novel Prize, Kamachi was contacted by Kazuma Miki, an editor at ASCII Media Works who had him write several test novels. He got the chance to write a full series and decided to create it with the concept of exploring the rules of magic, rather than just having it exist, and the inclusion of science to oppose its elements. The resulting series has seen success with both critics and audiences, with critics praising the action and characters.
A manga adaptation by Chuya Kogino began serialization in Monthly Shōnen Gangan in April 2007. J.C.Staff produced two 24-episode anime television series between 2008 and 2011. An animated film was released in February 2013. A 26-episode third season aired between 2018 and 2019. Several spin-offs and other adaptations have also been made, including several video games.
Synopsis
Setting A Certain Magical Index is set in a world where supernatural abilities are a reality. Individuals who possess special powers acquired via science are called . Those Espers who gain their abilities without the aid of special scientific instruments, whether at birth or otherwise, are referred to as . Others, known as , gain their powers upon mastering the power of magic, either from obtaining knowledge from different mythologies or by using mystical artifacts, although the existence of sorcerers is a secret to the public. While Sorcerers align themselves with different beliefs, Espers are aligned with scientific institutions. This leads to a power struggle between the magic and science factions for control of the world.
Plot The story is set in , a technologically advanced independent city-state located in the west of Tokyo, Japan, which is known for its educational and research institutions. Toma Kamijo is a student in Academy City whose right hand's power called the Imagine Breaker could negate any supernatural powers but also his luck, much to his chagrin. One day, Toma meets a young English girl named Index, a nun from Necessarius, a secret magic branch of the Church of England, whose mind had been implanted with the Index Librorum Prohibitorum – 103,000 forbidden magical books the Church stored in secret locations. His encounter with her leads him to meet others from the secret worlds of science and magic. Toma's unusual power places him at the center of conflicts between the Sorcerers and Espers in Academy City who planned to unravel the secrets behind Academy City, Index, and Toma's special power.
Besides its manga adaptation, the series also has spin-offs focusing on the level 5 espers, the top ranked espers in Academy city. One of them is A Certain Scientific Railgun, which focuses on Mikoto Misaka, an Electromaster and the third most powerful Esper in Academy City. The second, A Certain Scientific Accelerator, focuses on Accelerator, a teenager capable of controlling vectors and the most powerful Esper in Academy City. The third, A Certain Scientific Dark Matter, deals with the second most powerful Esper in Academy City named Teitoku Kakine and his past. The fourth, A Certain Scientific Mental Out, follows the fifth Level 5 Esper and most powerful psychological psychic named Misaki Shokuhō in her election campaign for the next president of Tokiwadai Middle School's student body.
Development Kazuma Kamachi started his work with A Certain Magical Index when he received a call from Kazuma Miki, the light novel editor, after his submission was rejected at the 9th Dengeki Game Novel Prize (now Dengeki Novel Prize) in 2002. Miki began to train him in writing multiple test novels, including a story about a girl sister and a boy with a mysterious arm that became the basis for his light novel.
In his essay titled "If It's Interesting Anything Goes: 600 Million Copies Printed—The Day in the Life of a Certain Editor", Miki stated that the light novel was originally called but he chose the current title because the word "Index" left a "strong personality in the sense and direction" upon his reading of the manuscript. Kamachi revealed that Index's name was derived from the kanji he found from looking in the encyclopedia since he wanted a name that would "stand out for the character the story was centered around". He avoided using difficult kanji for Toma Kamijo's name to help readers able to read it but he kept the meaning behind the character's epithet ("The One Who Purifies God and Slays Demons") a secret for now.
When it came the time to write the story, Kamachi investigated the terms "sorcerer" and "real" online for him to build the world of magic and the magicians' existence in his light novel. He also realized that most other Dengeki Bunko novels had magic as a main theme; however, none of them actually invested much into its inner-workings. As such, he decided to use this as the premise for the series. In setting up the world of science, Kamachi "needed some kind of power to oppose" the magic side. This helped him to create the idea of Toma Kamijo's known power, the Imagine Breaker, and set the stage for the world-building of Academy City "where science, espers, and magic would gather".
Upon the release of the first volume of the light novel, Miki stated that "(to be blunt) it sold like crazy. Shortly after the official release date, we had to do a reprint half the size of the original printing. It was on a Monday. I still remember it now. It was quite an achievement for an unknown newcomer". After the success of the first volume, the second volume was completed in 17 days. Subsequent volumes were also completed quickly, with the story for the ninth volume completed before the release of the fifth volume.
Media Light novels
A Certain Magical Index is a light novel series written by Kamachi and illustrated by Kiyotaka Haimura. ASCII Media Works published 25 volumes between April 10, 2004, and August 10, 2011, under their Dengeki Bunko imprint; 22 comprise the main story while the other three are short story collections. On May 4, 2021, all volumes were free to read for one day in the Dengeki Novekomi app developed by Kadokawa Corporation. Yen Press licensed the series in North America in April 2014, which began releasing under their Yen On imprint in November, and its omnibus edition in November 2022.
A sequel series, titled , began publication on March 10, 2011 and concluded on July 10, 2019, with the publication of its 23rd volume. On May 4, 2021, they began to be published in the Dengeki Novekomi app. A third light novel series, titled , began publication on February 7, 2020. Yen Press has acquired New Testament for English publication.
Kamachi wrote short novels exclusively for Haimura's three artbook collections. The first short novel, titled A Certain Magical Index SS: Love Letter Competition, was included in the release of Kiyotaka Haimura Artbook rainbow spectrum:colors on February 28, 2011. The second short novel, titled New Testament: A Certain Magical Index SS, was included in the release of Kiyotaka Haimura Artbook 2 rainbow spectrum:notes on September 9, 2014. The third short novel, titled Genesis Testament: A Certain Magical Index SS, was included in the release of Kiyotaka Haimura Artbook 3 CROSS on May 9, 2020.
The bonus novels that Kamachi wrote for the series' Blu-ray/DVD releases were compiled into four volumes titled , with the first two released to commemorate the 15th anniversary of his debut. They were published from June 10, 2020 to February 7, 2025.
A spin-off novel series written by Kamachi and illustrated by Nilitsu focusing on the women belonging to Academy City's dark side, titled , was announced in January 2023. The first volume was released on March 10, 2023.
Manga
The series has been adapted into two manga series. The one based on the novels is illustrated by Chuya Kogino and started serialization in the May 2007 issue of Square Enix's Monthly Shōnen Gangan. The first volume was released in Japan on November 10, 2007. As of September 11, 2026, 34 volumes have been published. Yen Press has licensed the series in North America and has been publishing the manga since May 19, 2015. The manga is also licensed in Italy by Star Comics.
The other manga adaptation based on A Certain Magical Index: The Movie – The Miracle of Endymion is illustrated by Ryōsuke Asakura and was serialized from February 12 to October 12, 2013. Square Enix published the first volume on August 27 and the second one on October 22.
Spin-offs
A side-story manga series illustrated by Motoi Fuyukawa, titled A Certain Scientific Railgun, started serialization in the April 2007 issue of Dengeki Daioh. As of March 2023, 18 volumes have been released. Its spin-off, titled A Certain Scientific Railgun: Astral Buddy, was serialized in Dengeki Daioh from April 27, 2017, to July 27, 2020. It was published in four volumes. A second side-story manga series illustrated by Arata Yamaji, titled A Certain Scientific Accelerator, was serialized in Dengeki Daioh from December 27, 2013, to July 27, 2020. It was published in twelve volumes. A third side-story manga series illustrated by Nankyoku Kisaragi, titled , was serialized in ASCII Media Works magazine Dengeki Daioh from August 27, 2019, to March 26, 2020 (the same day the compiled volume was published). A fourth side-story manga series illustrated by Yasuhito Nogi, titled , began serialization in Comic Newtype website on July 27, 2021. As of February 25, 2026, five volumes have been published.
A yonkoma manga spin-off illustrated by Mijin Kouka, titled , was serialized in Square Enix's Monthly Shōnen Gangan magazine from September 12, 2013, to May 12, 2016. A total of five volumes had been published in Japan from February 22, 2014, to May 21, 2016. In March 2023, Kamachi revealed the manga adaptation of A Certain Dark Item by Strelka, which is serialized in Dengeki Daioh magazine starting October 26 of that year.
Anime
A 24-episode anime adaptation of A Certain Magical Index was produced by J.C.Staff and directed by Hiroshi Nishikiori, which was aired in Japan from October 4, 2008, to March 19, 2009. The anime was collected into eight Blu-ray and DVD sets, which were released from January 23 to August 21, 2009.
A second season titled A Certain Magical Index II began airing in Japan from October 8, 2010, to April 1, 2011 and was also streamed on Nico Nico Douga. The second season's eight volumes of Blu-ray/DVD sets were released from January 26 to September 22, 2011.
An animated film titled was released in Japan on February 23, 2013. It is based on an original story written by Kamachi and features the main characters from both Index and Railgun anime series, along with the new ones designed by Haimura. The Blu-ray/DVD set of the film, which was released on August 28, is included with a bonus anime titled A Certain Magical Index-tan: The Movie – The Miracle of Endymion... Happened, or Maybe Not.