We tank him amongst the taurens, there aren't that much help, the positioning is more so that we can use Thrall and the NPCs around him for the Doomguards and so the offtanks and offtank healers can be 100yards away from him to avoid Doom. During the waves we focus on saving as many NPCs around Thrall as possible from Infernals etc.
This fight is always slightly easier the first time you do it, cause there is a group of NPC walking from above down to Thrall and before mid-fight they will reach your Doomguard camp and almost all of them are ranged dps (and totems that heals a lot), they will help down the Doomguards really fast, however, this pack does not respawn if you wipe.
If DPS on Doomguards is low, you should have hunter pets (they die instantly in the rain of fire anyway) on them as well, and position the hunters so they can run a short distance and help nuke the Doomguards down of needed. Offtank should never have more than 2 Doomguards on him at the same time.
A tip is to spread out and give everyone a set position before you start the trash waves, so that everyone knows where to stand, we have this on farm, but still do this positioning.
Use SS and Combat Res to get the ppl that get Doom up. We have had kills with everyone alive at the end, a few shamans got it, SS and CR used and it is also possible to resist the Doom.
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