Twenty years ago, there was a prophet who predicted the birth of the Calamity. As if to corroborate that prophet's prediction, over the past ten-odd years, perhaps as an omen of the Calamity's birth, the strength of monsters has dramatically increased, and Humans alone could no longer resist.

Therefore, the Emperor of the Empire that unifies Humanity issued an imperial decree to summon a Hero from another world.

And so, through the expenditure of tremendous effort and magical power, the Hero summoning was finally successful.