A remarkably easy achievement if you've got strong dps, but one that few guilds have even attempted (0.04% of 10-strict guilds have it, and 2% of 25's). All that must be done is to round up 9+ Guardians during P1, and aoe them down. Since their explosions upon death will hurt each other, killing one when they're all pretty low will spark a massive chain reaction!
We used the following makeup:
- 3 tanks - prot pally, prot warrior, bear
- 1 melee dps - DK, his offspec was a pvp spec for faction champs, otherwise he'd've gone tank too
- 3 healers - it was a fight to keep everyone up through the volleys and range
- 3 ranged dps - aoeing their hearts out. We had two locks and a hunter.
As we ran in, we had two tanks stand at maximum heal range: ~35 yards from the healers. There are several mods available that will let you judge your distance from a target, including IceHUD and Simple Range Indicator. Our feral druid, hunter, and DK ran around tagging every cloud they could reach, while the healers hid by the door. Healing aggro drew the Guardians towards the tanks, who picked them up; the feral druid went bear after cat-sprint-tagging some clouds and helped to pick up the mobs.
Make use of enemy nameplates to monitor the Guardians' relative health levels to make sure they're pretty even, and that none of them die too early. DPS stayed light until all 9+ guardians were in place and the tanks had sufficient threat, and then the AoEing began. This went very quickly, though it was hectic as we shuffled around to keep out of volley range but within heal range of the tanks, and dps range of the mobs. Tanks should try to stay on the side of the swarm of mobs that is closest to the healers, to aid range.
Once one exploded, they went off like dominos. They all fell within a second of each other in one huge, deadly explosion of death for anyone in range: being our melee. With 4 of our raiders dead, we opted to wipe and reset the fight before going for a Yogg speed-kill :) With two soulstones and two battle-resses, though, we technically could've gone on to kill Yogg after getting the achivement, had we decided to do the explosion right on top of Sara! It took one of our weeks of Yogg +0 attempts, but it was worth it, and a lot of fun!