Question about Frontier (Slaughter)

Sorry if my english is not that good, but it is not my native language.
The thing is, how can i unlock this pvp mode? I read in so many places that i need to do the "Like civilized Men and Women" quest, and i completed it, but i still dont have it. I need to do something else? Or it is a bug? Because i tried like everything and nothing seems to work because i only have the wolves den and the borderland ruins (secure) modes.

Thx in advance

Talk to the npc near the airship landing in your GC's hometown. You probably already have it unlocked b/c you have the other frontline, but just need to talk to the npc again to update your DF list.

That's all I had to do, anyway.