The first volume of the 'A Certain Magical Index' light novel series, written by Kazuma Kamachi and illustrated by Kiyotaka Haimura, is published, marking the start of the franchise.
The anime adaptation of 'A Certain Magical Index' begins airing in Japan, significantly boosting the franchise's popularity and reach.
The first season of 'A Certain Scientific Railgun,' a spin-off anime focusing on Misaka Mikoto, airs, expanding the franchise universe and fanbase.
The second season of the main anime series airs, continuing the storyline from the original series.
The second season of the 'Railgun' spin-off begins broadcasting, maintaining momentum for the franchise.
The third season of 'A Certain Magical Index' airs, concluding the main storyline adapted in anime form.
The fourth season of the 'Railgun' anime series is announced, continuing the spin-off's story.
Foundation and initial development of Academy City as a hub for esper research and education.
Academy City develops the power curriculum to train and enhance espers through scientific methods.
Birth of Misaka Mikoto, one of the main espers and Level 5 esper in Academy City.
Start of the Sisters Project to clone Misaka Mikoto for scientific and military purposes.
Touma Kamijo encounters Index for the first time, beginning their intertwined fate.
Massive conflict involving espers, magicians, and various factions battling within Academy City.
Kamijo Touma and allies disrupt the Sisters Project, saving many clones from being killed.
Introduction of the Magic World and its conflicts intersecting with Academy City.
Kamijo and his friends combat a faction within the Roman Catholic Church attempting to seize power.
Resolution of the Level Upper underground group's activities that affected many espers.
