Origin Emperor, Ancestor of Armies

[Alternate history + ancient warfare + passionate action + growth + slow-paced] A true man should take up a three-foot sword and achieve a feat for the ages. When righteousness calls, even if a thousand stand in his way, I will go! A modern young man transmigrates and is reborn as the son of a fisherman in a fishing village, only to discover that the world is locked in a struggle between warlords, with constant warfare. Forced to leave the village, he trains an army, upgrades its weapons, and revolutionizes its tactics. With an iron-fisted tide, he reshapes the rules of war, then sweeps across the Six Kingdoms and unifies the realm. Later historians call him Emperor Yuan, while military strategists of later generations honor him as the Ancestor of War.