Affliction warlocks are necromancers who would afflict living things with a fel affliction or fel disorder that brings living things to a state of oblivion as time passes. Despite that fact, Chris Metzen claims that they aren't necromancers who can afflict living things with a necrotic affliction and bring a slow death to them. Additionally, despite the fact that warlock energy spreads like radiation, Chris Metzen claims that warlock energy is not a necromantic energy that can spread into the undead, those trapped between death and life, or a necromantic energy that exists inside the realm between death and life.
In order to understand who affliction warlocks are, one must understand that Chris Metzen is a liar. Even if holy magics and shadow magics are cosmic forces, Chris Metzen would say that they aren't cosmic forces that specifically affect (or touch) the cosmic systems of the physical universe and govern their destiny lest they be the forces of Order and Disorder known as arcane magic and fel magic. He would say that fel magics aren't cosmic forces that mortals are gifted with by fel governors in exchange for their service as power-addicted felsworn priests who utter fel curses — prayers answered by demons.
Connection With The Fel Demons Of The Burning Legion And Demonology
Fel energy is described as demonic and, as such, is probably an energy that demons would gift mortals with in exchange for servitude as affliction warlocks.