Blood of a Fallen God by Joshua Cook
William Reis had no interest in ever being a hero. His goal in life is to join the prestigious Smithing guild, something no one from his city has ever achieved. When a pair of ancient artifacts are discovered by his Duncan his cousin, it unleashes a terror that will change everything.
When the artifact known as the Blade of Valnijz injures Duncan, Will is horrified to discover that the wound is cursed. His cousin is slowly transformed into an inhuman killing machine, driven by magical blood lust and rage. And only a dead god has the power to restore his humanity.
To save his family, to save the only world he has ever known, William Reis must do the impossible whether he wants to or not. He must become a figure out of legend, he must become a Forgemaster.