A Certain Magical Virtual-On

Toaru Majutsu no Virtual-On
とある魔術の電脳戦機

Source

A Certain Magical Index
Toaru Majutsu no Index· とある魔術の禁書目録〈インデックス〉
manga

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 — the 103,000 forbidden texts of the Church.

Alternative

A Certain Magical Virtual-On
Toaru Majutsu no Index x Dennou Senki Virtual-On: Toaru Majutsu no Virtual-On· とある魔術の禁書目録×電脳戦機バーチャロン とある魔術の電脳戦機〈バーチャロン〉
novel

In Academy City, there is a popular next-generation contest. In reality, this is a hand-to-hand battle between gigantic Virtuaroids that appear on the streets. It's formally called as "Computerized War Machine Virtual-On". Since it can be argued that Level 5s and Level 0s are equal given the technique, it has spread with explosive force among the students of Academy City. One day, Index with her white Bal Bados, fights Touma's stock Temjin. "I'm Ririn. Furashina Ririn. I'm not Ririna... Munya..." A seemingly insomniac girl arrives at Academy City. And, Kamijou has an encounter. The usual Virtual-On meets an unavoidable unprecedented accident. That is, the Computerized War Machines fuse with Academy City, a sign of a grand battle about to happen! Misaka Mikoto and her Raiden, Shokuhou Misaki and her Angelan, as well as many others will make appearances! (Source: Toaru Wiki) *Note: Includes a prologue and epilogue.*