Ok so I've been wondering about this since cata's realease. This will make alot more sense if you have played through the death knight starting area.
After the battle for light's hope chapel the ebon blade DK's are freed from the lich kings control and are sent to either Varian or Thrall depending on your race.
This is where you have to seperate game emchanics from storyline mechanics.
For gameplay issues Death knights are either part of the alliance or part of the horde depending on your race. fair enough
However lorewise death knights are still part of the Ebon Blade and are only allied with the alliance or the horde.
So (finally) this is my question. During the Battle for Andorhal questline you can see that Thassarian is clearly part of the Alliance and Koltira is part of the Horde officially.
Shouldn't the Ebon blade (a neutral faction) be neutral in a war between the Alliance and the Horde and these 2 shouldn't get involved? I relise this could count for player death knights aswell but that would just be awkard game mechanic wise and to be fair they arnt leading the Alliance or Horde forces during the fight.
Have I missed something is there a clear reason for this?
Also where has Darion buggered off to in cata?