Vogun the Corruptor

Vogun the Corrupter is a mad spirit. Though his origins are unknown, it is common knowledge to those that know of Vogun that he has been anchored to The Etherium. Though his body cannot roam outside the realm, his mind jaunts whenever possible to the physical world where he attempts to corrupt spellcasters into aiding his quest for release. If slain, it appears he just returns to his point of binding,meaning that death is only a minor setback for the corruptor.

Origins
The closest any historian has come to placing Vogun is that he was once a demon of near diety-like power. It is unknown what shadowy master Vogun serves, but he reappears many times throughout history and folklore.