In a world where humans enslave otherworldly species, the great mage Rifenhardt stands as their only protector—earning him the infamous title of “Demon King.” A party of heroes is dispatched to eliminate him, but despite gravely wounding them, Rifenhardt falls to the might of the continent’s strongest warrior, the Martial King, Tesslon.

With his last breath, he casts a desperate Time and Space Regression Spell… and wakes up in the past. But fate has played a cruel trick on him—he has become Tesslon himself, the very man who once struck him down!

Now, armed with both unparalleled magic and overwhelming martial strength, Rifenhardt embarks on a new journey—to change the world and free the oppressed!