The Masks of Janus (Imperium Volume 2, Book #4)

Truth Comes to Light
Britannian forces continue to push east against the invaders, taking the fight into Asia Minor and the Middle East, but the struggle is brutal. The easterners have shown again and again that they have the ability to copy Britannian weaponry at a startling rate, limiting how long the West could maintain technological superiority to counter the east’s numerical superiority. At the heart of that ability is a secret that explains much of why this timeline was different from the one in Ky’s history files.

The answer to that question could change the nature of the war, and the fate of the West hangs in the balance.