From publisher blurb:
Souldrinkers learn the worst of daemonic magic while gaining the ability to bind and devour souls. With every soul they consume, these casters tithe a fraction to their patrons. They are the proxies of death, serving the architects of the apocalypse until eventually their own souls are drawn into their masters’ waiting maws.
Prestige Class: Souldrinker
Build Classes: The souldrinker is built on the wizard, but the following alternate build classes are described below: arcanist, cleric, oracle, psychic, sacerdote, sorcerer, or witch.
Role: A souldrinker seeks to collect souls for personal power, and as bribes to their daemonic masters.