Realm: Mistblade Patchwerk won't spawn during "The battle for the Ebon Hold" quest - can't progress as DK

[Konradius]

Well - that is pretty much it. I have tried everything I could think of. I relogged, I abandoned the Quest, I abandoned the quest and relogged but to no avail. He won't spawn. Well, actually he does, but he becomes invisble after a splitsecond and there is noc way to target him  or anything. He is basically or practically gone. I don't know, if he really is gone or just not visible or targetable or whatnot, but it is impossible to end the quest and therefore impossible to leave Ebon Hold. I have no  idea, why this might be. Do you?

(Realm: Mistblade (Season 2); Character: Tyetodeath)

[coyle93]

Same thing happens me.  If I exit the game and log in he's visible for a split second and then disappears I've tried standing under him when I log in but nothing, he disappears immediately.