R-18 (Notice the chapter contains sex scenes)
"What? You can't joke with me Major, I'm just a Duke who deals with business and land, my heart can't take this kind of joke "Oji said, paling quickly.
The agents of Chaos are the Vampires, but this is a formal way of addressing the cursed race. Of course, that Oji went pale, it was no joke to be on the side of the vampires it was to be against the entire universe.