Three Kingdoms: You Were Told to Guard the Border, but You Went and Conquered Korea

After working himself to death, overworked office drone Gongsun Yue transmigrates into the body of Gongsun Zan's forgotten illegitimate son. From the start, all he has is a godforsaken little city in Liaodong and a hundred soldiers who are old, weak, sick, or disabled.

At the brink of despair, the [Empire-Building War Room] System activates. With every victory, he can choose between [Technological Innovation] and [Military Evolution]!

Recruit Zhao Yun from the start~~~ Steal the goddess Zhen Ji from Yuan Shao

After wiping out bandits, he chooses [Hundred-Forged Steel Technology]. The ring-pommeled swords he forges cleave Xianbei cavalrymen and their horses in two!

~To repel foreign invaders, he chooses [Repeating Crossbows]. Thousands of arrows fly from the city walls, and beneath their rain, everyone is equal! While Yuan Shao is still relying on cavalry charges, Gongsun Yue has already positioned his [Crouching Tiger Cannons] atop the walls of Ye City.

~Cao Cao: “Gongsun Yue's weapons are no ordinary things. They're the sorcery of demons from beyond the heavens!”

~Liu Bei: “How can the three of us brothers be unable to defeat even one battalion of his iron troops?”

~Years later, when Gongsun Yue's armies reach Luoyang, the warlords of the realm finally realize in terror that the poor boy from Liaodong has quietly built an empire of steel!