Since I didn't want to fight Ul-Dagan immediately when Erdu asked me, and wasn't sure if I'd be thrown into a battle, I said that no, for now I wouldn't start that questline. I assumed, perhaps foolishly, that I'd be able to come back later, apologise, and help him after all. Apparently I was wrong. Is there a way to start the quest now? I've not gone onto any other shards since he turned up, just talked to other masters.