Try to clear the respected area on distance. Flameond will only dig him self out of the ground, when you come near. This way he´ll stay alive. And do not forget to switch off any hurting auras or minions.
Keep in mind he spawns by burrowing out the ground and won’t do so until you get really close to his spawn. You can actually stay at a distance from his spawn and lead any nearby Aetherials back to you or take them out from a distance before checking his spawn spot properly.
I find clearing a route from the portal to his spawns (as you check them one by one), then clearing the surrounding area as above, then checking (disable any AoE damage auras as well) is the easiest way to find him and get him back to the portal.
Thanks for the info, guys; restarting worked. No question; killed the sucker first time through. Didn’t know it was hostile and never noticed when he showed up. Was a lot more careful the second time.
Finished up a little while ago. Funny thing about that Bonebleach Basin. For some reason, those camels made me think of…cows. Heh.
I always try to clear the whole place even before I start the quest-line. This will give me completely free path in guiding the blue dude to the ritual circle. Note this has to be done in a complete session.