Bullet Code: Firewall

is the first volume of the Bullet Code light novel series, written by Suzu Saito and Illustrated by Wata. It was released under the Dengeki Bunko Imprint in February 2021.

Synopsis
"Project Firewall". It was "war experience learning by VR" that was to be imposed on young people to prevent the tragedy of war. The practice, which should have been more than just "playing", suddenly turned into a chaotic program. Unplanned soldiers-No, the assault of a "mysterious enemy" who is not even a human being, and the danger of the approaching "death in reality" ... Along with a high school classmate, Yuma Furuhashi, a boy who was involved in this abnormal situation, is helped by a team led by Chitose Amemiya, a girl with the nickname of "Frostbiter", a soldier with the fourth highest grade in the world. The last thing they see as they overcome conflicts and tragedy and approach the truth of the project-- !?

(source: Dengeki Bunko Official Website - Translated)