Wei and Jin: Start with a Fort to Create a Torrent of Steel

[System + infrastructure + decisive killing + industrial revolution + no female protagonist/single female protagonist] In AD 304, the Five Husbands invaded China and the land of China sank. The son of the Han family was regarded as a "two-legged sheep", and his life was like a piece of grass. Chang Yi, a special soldier, traveled through time and faced a siege of hundreds of cavalry at the beginning. It was a matter of life and death! Fortunately, I awakened [Civilization Exchange System] No weapons? Exchange it for a high carbon steel dagger and cut iron like clay! Cavalry charge? Rub the Molotov cocktail with your hands and let Hulu die in the sea of ​​fire! Can't defend the city? Cement, blast furnace, and gunpowder create unbreakable barriers! Starting from a small fort, Changyi gathered refugees, built fortifications, and advanced technology. While the barbarians were still wielding rusty machetes, Chang Yi had already raised the first modern disciplinary force. When the Hu cavalry tried to go south again, what awaited them was a torrent made of steel! Chang Yi: "I also want to keep a low profile, but my shooting range doesn't allow it." Let's see how he uses steel and flames to recast the backbone of the Han family!