Reborn in a Good-for-Nothing Body, I Go on a Rampage with Ten-Thousandfold Returns

My name is Liu Ji. I was once the Sword Emperor, whose mastery of the sword reached the divine, but I was reborn as the Liu family's discarded good-for-nothing. In this world, cultivation reigns supreme, and the nine great continents are teeming with powerful experts. From the start, I awakened the Ten-Thousandfold Retribution System: kill me once, and ten thousand times the damage will be returned. Every sword cultivator in the city will perish with you. Even more absurdly, I picked up a deranged nun at a ruined temple. Every time she loses her mind, I unlock an ancient sword intent. Others toil in cultivation for ten years, while I reach the highest level after a nap. My clan bullies me, sects oppress me, and an Immortal Emperor tries to destroy me? Excellent. I'll pretend to be useless and build up my strength. I've been waiting for the moment you make your move. In this life, I don't reason with anyone. I only wield my sword.