Affliction

An affliction is something such as a disease or a curse that causes pain or suffering. Some warlocks specialize in afflictions and learn to master curses and long-lasting spells, as well as various other ways to weaken their opponent. They rely on slow, steady, and agonizing deaths.

Description
Indulging in fel energies that wither away their life force over time, affliction warlocks are the masters of shadow magic. Unlike shadow priests—deadliest when pushed to the brink of insanity—affliction warlocks in particular delight in using fel forces to cause intense pain and suffering in others. They revel in corrupting minds and agonizing souls, leaving enemies in a state of torment that would see them undone in due time. Even the most battle-hardened warriors can be deceived, landing blow after blow against the warlocks, only to succumb to their suffering as their very vitality is siphoned away by the dark spellcaster.