Black Necromancy
Historians of magic believe Black Necromancy to be one of the oldest types of magic, having grown out of research to defer or even forestall death. Because the practice of Black Necromancy necessarily involves the manipulation of anti-magic, its practitioners invariably suffer gruesome and ultimately debilitating physical effects, though most choose to transform themselves into undead before such effects prove crippling or fatal.
Gods consider Black Necromancy, Black Necromancers, and all undead antithetical to their Creation, thus exhorting their clergy to destroy these at any opportunity. The largest organization dedicated to the eradication of undead is the Knights of the Righteous Light, a warrior-cleric order under the patronage of Re, God of Sun and Fire.