Rentaro Satomi and Enju Aihara, both forming part of the organization Civil Security, fight together in hopes of returning light to mankind. Enju, commonly referred to as a Cursed Child due to her connection with Gastrea; along many other young females, aids Rentaro Satomi in a special mission given to them by the government. Kisara Tendo, leader of the Tendo Civil Security Corporation, guides said characters in their missions against the Gastrea parasites.

After a Gastrea invades the Tokyo Area on April 28, 2031, Seitenshi summons Civil Securities to a meeting, informing them of the threat approaching the Tokyo Area. The many Civil Securities ready for combat as they depart to hunt for Kagetane Hiruko, Kohina Hiruko and the Legacy of the Seven Stars.

Black Bullet (ブラック・ブレット Burakku Buretto) is a light novel written by Kanzaki Shiden and illustrated by Ukai Saki, and a manga series illustrated by Hon Morino. Serialized under the Dengeki Maoh magazine since August 27, 2012, Black Bullet is an ongoing manga series that has its individual volumes published in tankōbon format by ASCII Media Works. The first volume of "Black Bullet" was released on May 27, 2013 with one hundred sixty-four pages in total. The light novel has released six volumes as of October 10, 2013, with an anime series announced on October 6, 2013. The anime is set to premiere April 8, 2014.

The series follows the downfall of mankind at the hands of the viral parasites Gastrea. Living in despair and horror for ten years, the humans barricade themselves within Monolithic walls and are protected by the organization Civil Security Corporation, which specializes in fighting against Gastrea. Rentaro Satomi, Promoter of Tendo Civil Security, fights alongside Initiator Enju Aihara in the dangerous tasks given to them by the government.