Slacking Off to Save the Empire

Ethan Cole, a modern office worker, transmigrates as a Ming imperial guard. He awakens a Slacker System: slack at work, invincible after hours. After killing a demon elder, he's sent to the Entertainment Bureau. There he recruits assassin Selena Ward and meets the emperor. Using after-work power and office tricks, he beats corrupt officials and demons. He defeats the demon lord, but oil discovery forces him to work overtime again in the west.