I also had the Warmaster just disappear in front of me. Talking to him, got some quests, and *poof* he disappeared. No messages why; nothing. 15-20 minutes later I had a 'find a new Warmaster' quest. I had to look in the log so as to find what happened. Turns out he was starving and died... all apparently while I was getting quests from him. But there was no wail of pain, no dying, no body, no status info... he just disappeared.