[Valtain]

I learned Cull I tonight. Here is how:

Travel to Trengal Keep on the Thestra continent. Within the keep are level 30 4 dot Death Knights and Warlocks. These are the mobs we learn the skill from. These mobs are located in the South eastern corner of the keep. I was able to solo these at level 42.

When you get the first identification you will receive a message stating that your understanding of Cull I has advanced. You need 10 of these updates to learn the spell.

Cull I
134 Energy Offensive Target
Evocation Cast: Instant
Range 25
Refresh 10.0

Drains 408 to 423 health from an opponent.
Only Usable when opponent is stunned.