Light novel series written by Kanzaki Shiden and illustrated by [[Ukai Saki]]. Also adapted into a manga by [[Morino Hon]], serialized in ASCII Media Works' Dengeki Maoh, and a 2014 anime produced by Kinema Citrus and Orange.

The story involves humanity threatened by a pandemic known as Gastrea since 2021, and thus are forced to confine themselves within barriers known as Monoliths, made out of a special metal, Varanium, which is capable of subduing the Gastrea.

h4. Main characters
* [[Satomi Rentarou]]
* [[Aihara Enju]]
* [[Tendou Kisara]]
* [[Tina Sprout]]

h4. Supporting characters
* [[Hiruko Kagetane]]
* [[Hiruko Kohina]]
* [[Seitenshi (black bullet)|Seitenshi]]
* [[Shiba Miori]]
ブラック・ブレット