Fight begins with keeping boss away from group. They wait at entrance, tank goes where boss spawns. This is first flame phase. Once it starts it will repeat every 60 seconds. Start running back to group to bring them boss. Stay on side to “shake off” fire AOE and spawn Fire Atro. Group have 60 seconds (counting from when fire phase began) to take boss down to 75% HP (in full burn strat). Practically its about 40 seconds. Time your taunts. At 75% the healer takes over main boss. You take away two minibosses all the way across the lava river. On a side note this is where flame AOE timer resets (another 60 seconds to take boss down to 50%).
With bosses away group does not get hit by meteors or champion wont heal boss. Being that far away you avoid completely first pull phase. When its done you can start heading back to intercept two new adds. Two new adds spawn. Taunt all four of them (the two previous too) and again get back all the way behind lava. Do it as fast as possible because second pull phase is imminent. Stay alive, keep aggro on all 4 minibosses. If you do that its all up to DPS and healers to finish off boss..
As found on Youtube