Toaru Anbu no Item (light novel)

Toaru Anbu no Item (とある暗部の) is a Japanese light novel series written by Kamachi Kazuma and illustrated by Nilitsu; the series is published by ASCII Media Works under their Dengeki Bunko imprint.

Background
During the 3.5th anniversary livestream for Toaru Majutsu no Index: Imaginary Fest, a new side-story focusing on the dark side group Item was announced, titled Toaru Anbu no Item, for release in March 2023.

Plot
In Academy City, where esper abilities have been recognized as a general science. Behind the peace, there is a dark side organization that undertakes missions that cannot be made public.

"ITEM" is an elite unit consisting of four girls. Takitsubo Rikou is able to read and track the weak power emitted by those with abilities. Frenda Seivelun, who excels in combat using explosives and traps. Kinuhata Saiai, who can manipulate nitrogen at will and plays a defensive role. And one of the 7 espers that Academy City is proud of: Mugino Shizuri. They live freely in the darkness of the Academy City, and quietly set their sights on their target...!

This is a story of encounter, friendship, and darkness that eventually leads to a 'terrible incident'!