From the Start, I Was a Mine Slave in the Kingdom of Women. I Made Weapons and Became a King

Shen Zheng, a researcher at a modern weapons laboratory, unexpectedly transmigrated to an ancient kingdom of women and became a mine slave. For every woman he recruited, the kingdom's strength would rise by a whole tier in a contest against foreign enemies, from crossbows to cannons, from a weak nation to a hegemon.