It's a Showdown. I'm the Feudal King and an Arms Dealer.

Travel through time and become the most insignificant vassal king in the middle of the Ming Dynasty - King Dai, whose fiefdom is in barren Shanxi. He awakened the [Super Arsenal System], which can unlock a full set of military technology trees from matchlock guns to breech-loaded rifled guns to steam ironclads. But he chose a different path: instead of rebelling, he started an arms business. Internally, he sold "captive-suppressing artillery" to the imperial court to help the border troops resist the Mongols; he then sold the eliminated "magic guns" to the Mongolian tribes, causing them to fight among themselves. King Yan, King Ning and other careerists want to buy weapons from him to rebel? Yes, the price will be increased ten times, and minerals, land and talents must be exchanged. As a result, the protagonist's fiefdom develops rapidly and becomes a center of technology, industry, and wealth.