Quills: the Rise of the Northern Matriarch - Chapter 40: Trust Issues

【Gunfight + Mystery-solving + Decisive Killing】I had already been backstabbing the underworld, and now you're telling me I was planted as an undercover cop???Dean looked at the boss with eyes that would not close in death, scratched his head, and could only take the opportunity to transform into Los Angeles' five-star good citizen—Detective Dean!Ps:There's nothing supernatural, but there is a dark world out of our ordinary reach, filled with assassins, thieves, and all kinds of bizarre cases...

A man was transported to Ancient China and eventually became a servant of a declining household without a male heir. He utilized his wits and modern knowledge to help the household and eventually become trapped in the sea of political turmoils of the period.

- Description from Novelupdates

Beings that create and control monsters and demons, beings that build and reign over malicious labyrinths, the chosen individuals to possess an overwhelming Unique Skill… They are the Demon Lords.