The Spy Life in the Demonic Sect

Iseo Jang, the Murim Alliance's prodigy spy, has spent 14 years deep undercover in the Demon Sect, earning the ruthless title of "Rabid Dog" for his work as their counterintelligence agent. But his newest mission is his most absurd yet: make the Sect's laziest, most notorious delinquent—Wu Ma—the next Cheonma. To pull it off, Iseo ditches his post and applies to be Wu Ma's official aide. In a world of betrayal, martial arts, and political games, can even a talent like Iseo turn a hopeless young master into an heir?

(Source: Webtoon Entertainment)