Toaru Anbu no Item

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—all the magical texts the Church has removed from circulation.

(Source: Wikipedia)

*Note: Includes 16 prologues, 18 epilogues, and 6 extras.*

The Academy City, where the pinnacle of science and technology converges to advance psychic development. But behind the seemingly peaceful and glamorous facade of this city lurks a “dark side.” The girls known by the codename “ITEM” are a part of this world. They form an elite unit composed of specialists in various fields, led by the Level 5 esper, Shizuri Mugino. When a new member joins “ITEM,” she will find herself drawn into a conspiracy lurking beneath the city's surface... 

(Source: Dengeki Daioh, translated)