Born into the Valgred assassin family—feared across the battlefield as the absolute reapers—Glenn is cast out into the freezing wilderness by his own father for being a sickly failure who cannot even train. Rescued from the brink of death by Emperor Willfoen Thorngrave, Glenn dedicates his entire life to serving him, eventually becoming the legendary hero who slays the Five Demon Kings and ends the war. However, his unyielding loyalty is met with cold-blooded betrayal when the Emperor dispatches nine mysterious assassins to murder him. Waking up thirty years in the past, Glenn retains all his ultimate martial techniques, vast knowledge, and even the absorbed powers of the Five Demon Kings, setting out on a path of unprecedentedly swift growth and vengeance.