A Void Dance

A Void Dance is a Lich King heroic achievement needed for the Glory of the Hero achievement, rewarding the Reins of the Red Proto-Drake.

Strategy
The main strategy here is to burn down the boss as fast as possible! This is a heavy healing fight: gathering up on the boss, and spamming AoE heals, along with every damage dealers doing a little more than 2'000 DPS should be enough to get this achievement. One thing to worry about though, is the boss's ability Shroud of Darkness. When you see this, you may want to stop attacking for 5 seconds, or you may end up with 4 people with a -100% healing debuff, or have someone who can dispel or steal his debuff.