The Ravenous refers to a set of arcane defilers that were consumed by the magic they wielded, and were warped physically and mentally into a debased form of themselves. Their racial identify is torn away, and replaced by the need to defile until nothing living remains.
The ravenous appear skeletal, emaciated and patchy, just like gaunt walking corpses. However, they still remain among the living - in areas abundant with life, they can sustain themselves without suffering additional decay. The presence of a ravenous is unmistakable, where crops wither and die for no apparent reason - neighborhoods can fall victim to an illness.
They were created by prolonged exposure to defiling magic through reckless use, compared to sorcerer-kings who successfully transformed themselves into demigods. The bodies of the ravenous are still filled with defiling magic which still sustains them as the cost.
Fourth Edition D&D provides three creatures: A Ravenous Sorcerer (Level 13 Elite Artillery), A Ravenous Champion (level 13 Elite Soldier), and a Ravenous Thrall (Level 13 Skirmisher). The sorcerer originated as a spellcaster who can drain the life of others. The champion used to be martially trained creatures that fell victim to ravenous hunger and are augmented by magic to make them more deadly. The thrall have been tainted by the hunger of the ravenous - while autonomous, they remain addicted to the presence of their defiling masters.
In combat, the ravenous thralls are sent forwars as cannon fodder. Ravenous champions attempt to engage the weakest enemy, while sorcerers provide support from a distance.
- Rodney Thompson, The Ravenous, Dungeon Magazine #193.