Without so much as a warning, humanity in its entirety was suddenly moved to another dimension. Every person without exception.

But this new world with all its opportunities and gifts of wondrous abilities, was a stadium. A deadly arena of an unimaginable scale. And Humanity were to be its latest gladiators. Every man, woman and child was given a weapon and ordered to fight. Stuck in this dimension without a way out, only two options existed for the would be hunters: Fight with monsters to complete the many trials ahead, or perish.

Faced with hordes of powerful monsters, thrown into battle with complete strangers at random, the unfair game of survival began. And from the very beginning, billions of lives were extinguished in mere moments. But even within this abyss of despair was a small ray of hope: If even one person were to complete every raid, then humanity would be redeemed and restored back to its former glory.

No save points, no revives, no retries. Everyone had just one life to make their way through the gauntlet of raids prepared to test their mettle. Within this marathon of death, one man becomes aware of an exception to the rules of the game.

King Grey once benefited from unrivaled strength, wealth, and prestige in a world governed by martial ability, but now finds himself reborn in a society dominated by magic. Given a second chance at life, the once-king strives to understand his role in this new world and the purpose of his reincarnation while correcting the mistakes of his past.