Originally Posted by
Harthorg
I think its about a 2 and half minute cooldown from memory.
and you dont need grip of death, you can use deathly blizzard, paint an area and then shatter up to 12 mobs at once.
So you could have a few necros painting an area with blizzard then shatter as shatter has a larger area then blizzard, you only need the blizzard debuff so you can just do blizzard to 1 tick, then cancel and do shatter straight after.
It will instant kill minions and i think even if its not killing it does quite a bit of damage for each blizzard debuff its breaking. You can also use touch of winter too as others have stated.