Military: I came from a different world during World War II to make equipment

Story of: Military: I came from a different world during World War II to make equipment

Unexpectedly, he passed through a new empire in another world, became the new Long Forest's eldest son of the Three Provinces, and obtained the "Weapon Maker System".
The first thing to do when returning home is to teach your three brothers.
Look again at how Long Forest rose up in a chaotic world, competed for domination of the world, and established a giant empire.