Necromancer

Neromancers are arcane practitioners who utilize the arcane to animate corpses, create undead creatures, and manifest ghosts. While other arcane users may experience physical side-effects such as slight aging or whitening of the hair, necromancers are different. Over time, a necromancer will actually become undead themselves. They will no longer sleep, eat, breathe nor age. However, they also become susceptible to anti-undead effects.

Origin
The origins of necromancy are hotly debated among many circles. Necromancy was certainly not created by mortals, but instead by demons as a means of temptation. Both neredar and dreadlords claim to have created necromancy, the former as a means of bolstering their armies, the latter as a means of manipulating mortals. Regardless of who created it, necromancy is now prolific across many different realms.

Arnen
Necromancy has completely fallen out of use on Arnen. Even the mere accusation of being a necromancer is enough for a visit by the Shadra Torr. Long ago when humans were first taught magic, an order of mages known as the Guardians of Tyr were created. These mages were responsible for tracking down and eliminating any and all necromancers, suspected or proven. The Guardians were highly successful in their purge, and ultimately victims of their own success. The Guardians had slowly dissolved over the following century, as its members all passed from old age. Now necromancy is so far removed from the lexicon of the denizens of Arnen, that many people don't even recognize the word.

The Slave Lords
The Slave Lords made extensive use of necromancy to create henchmen for slave markets. Skeletons cannot be bought, do not need to be fed, nor do they require sleep. Undead proved to be a powerful tool for the Slave Lords, a tool they continue to use until this day.

Grave Fleet
The vampiric world of Strahd was once home to necromancer and vampire both, who lived in relative harmony. However following a vicious purge instituted by the vampires, necromancers were forced to flee the planet. They took to the stars using their mastery of arcane. Dubbing themselves the Grave Fleet, these necromancer pirates sail wildspace in search of fresh corpses for their ever growing armies.