Thousand Kingdoms Ghost Soldiers

In the third year of the Great Famine, a timid fisherman ate a fish that glowed green. From then on, armies emerged from the mirage - the square shields of the Roman legions, the white fire of the Egyptian chariots, the soul arrows of the Assyrian archers, the silent charge of the Persian cataphracts... They came from forgotten history, and they only listened to his orders. However, the time when the mirage appears is uncertain, the number of people is uncertain, and the types of troops are uncertain. He can command the most powerful army in the world, but never knows when it will come next. And the enemy has found a way to restrain it - sun-dried sea salt, applied to the chest, can completely disable the undead's attacks. This is a man who has been crushed to the lowest level by fate, using the most uncontrollable weapons to fight a war that must be won. Core Settings -The troops summoned by the mirage each time come from different civilizations and will never be repeated. - Undead Bane is extremely cheap sun-dried sea salt, invincible in raids and disadvantaged in positional warfare. -The protagonist goes from "doesn't want to stand out" to "has to" to "no one can do it but me"