I've just stumbled upon some new dialogue between Koltira and Thassarian posted on Wowhead. They seem to be serving Bolvar now and act like Deathlord never existed. Here are the lines I find worrying:
Thassarian: The Helm of Domination has been shattered. A strange thought. For so long it has been a symbol of our curse and our duty.
Koltira: And now we wield our blades on behalf of the one who wore it.
Thassarian: Bolvar Fordragon is no longer the Lich King. If we are to take orders from anyone, I could think of far worse leaders to issue them.
Koltira: Like Genn Greymane, for instance?
Thassarian: Or Sylvanas Windrunner.
Koltira: Point taken.
Can anyone who has beta access please confirm or refute that Deathlord is no longer a thing?