Hero Emperor Crowley was humanity's strongest warrior. After defeating the demons and gaining immortality from the fruit of the World Tree, he was suddenly betrayed and murdered by his best friend, the Great Mage Raphael.

Two hundred years later, Crowley's soul awakens in the body of Faris, a lowly slave belonging to a ducal family. Even more shocking, he discovers that his original body never died—it is still out there, fighting endlessly at the World Tree as the "Hero Emperor"!

Why was he killed, and who is controlling his invincible body? To uncover the truth behind his murder, Faris strikes a deal with the Duke to shed his slave status. His new mission: become the butler and sword instructor for Rimuru, the disgraced and "incompetent" daughter of the family, and mold her into the perfect successor. The journey to the top of the World Tree to expose a 200-year-old betrayal begins now!