You Sent Me to Infiltrate the Underworld, and I Became the Dark Emperor?

Ye Feng, an undercover cop with China’s Bureau 749, received the most outrageous assignment of his life: Go undercover in the underworld. “Boss, it’s been three years, then another three years. I’m practically the Yin Emperor now. When are you going to let me come home? Lately, Ksitigarbha has been looking at me funny. I think he suspects me.” “Don’t worry about them. We’ll bring you back as soon as the mission is done. Can you stir up the underworld again within a year?” “Sure.” N years later. “Ye Feng, what’s going on? Why have so many vicious ghosts escaped from the underworld and started rampaging through the human world?!” “Sir, you can eat whatever you like, but don’t go spreading lies. Everyone in my underworld obeys the law.” “...”