The Orb Whisperer (25 player)

While I am sure most guilds capable of this achievement are saavy-enough to get it without reading Wowhead comments, here are a couple of things to do to make this easier:

(1) Ensure that the ranged tank on Keleseth always has enough Dark Nucleui on him (and/or coming to him). While my guild had a Mage Ice Lance the nucleui over to a Warlock tank, your strategy may be different. The easiest way to fail this achievement is if your Keleseth tank does not have ample stacks of Shadow Resonance during Empowered Shadow Lance.

(2) Empowered Flame - We had our melee almost run with the Empowered Flame after they spawned to ensure that the damage was completely a joke when it hit its target. If your melee takes 2-3 ticks each, the explosion won't even come close to 23k damage and the damage on melee is light.

(3) Empowered Shock Vortex - You simply cannot have more people standing on top of each other when this is cast. It is entirely easy for melee to get insta-gibbed as they run in the same direction or manage to run right over to where a ranged DPS or healer was standing. Your ranged shouldn't need to move (they should already be spread out) and your melee simply needs to "fan out." While I don't think it's possible for these to do 20k+ damage by themselves, a few of them combined will. Although you may still get the achievement, it's a little easier with most of your raid alive.

Cheers and good luck.

Whoa. Waayyy overboard with the talent build. The cookie-cutter demo build works just fine for this encounter.

Spec for me when I tanked the encounter and got achivement as warlock

http://www.wowhead.com/?talent#IZ0GchkAbi0cZVchVbIzAc0b:dj
make Prince Kelesth as your focus target and use this macro
/cast [target=Focus] Searing Pain

use fel puppy and soul link . then just spam the macro above. Whenever u see an orb appears, just run toward it and grab it with a rank1 CoA once it's in casting range. CoA rank1 only tick for 4-5 damage per tick, but it can make sure the orbs wont run away even someone accidently attack it, better than using CoT or CoW some strat suggested. Just fouse grabbing orbs, and spam the searing pain macro whenever u got all the orbs that was in the room on you. Key to this achivement is just never have less than 3 orbs on you through out the whole encounter.