When fortune smiles on one, calamity befalls another. Born into a lineage of legendary assassins, Jack Grim was forged in darkness—trained only in bloodshed and the art of the kill. At seventeen, his parents offered him a final contract: succeed, and the organization of his dreams would be his. It was everything he'd worked toward: the pinnacle of his profession, the life he was destined to claim. He completed the job under cover of night, claimed his victory, and received his promised reward. Then came the searing pain, the consuming fever— and in a moment of agony, transmigration pulled him away. Jack awakened as Raiden, guardian of the Book of Ashes—an artifact that served as the core of the Devourer itself, and the very tome the fallen Raiden had sacrificed everything to protect. Jack had no intention of being trapped in this foreign realm, regardless of what magic it contained. His sole focus was escaping back to his assassin's life. Yet destiny demanded otherwise. The fate of this world now depended on his guardianship of the book, and whether he accepted it or not, the burden fell to him alone.