Originally Posted by
Firespark
And which ones are those?
In-keeping with my explanation, warlocks who continue using it are fools, and doomed to lose their will. Transforming oneself into a demon does not come without a price; their selfish grasp for power opens the floodgates, and they soon lose themselves to the thirst for more. The more you take on the form of a demon, the more of a demon you become. It is easy to see how the demons became corrupt in the fist place.
Only Demon Hunters, their motives entirely selfless, can avoid this fate.