Total Drama Dungeon!
A renegade mage is the term for any mage who refuses to obey the directives of the Guild Arcanum. Most renegades are minor hedge-wizards who practice in secret. Given the vast power of the Guild, both temporal and arcane, any wizard who openly defies that organization must be both incredibly powerful and at least slightly mad. Renegades, if discovered, are mercilessly hunted down by both the Guild and the police forces of most nations.
Some notable renegades have openly defied the Guild and lived. One example was Johannes Kaeppler, a member of a prominent Guild family who was accused of dark practices and ordered to submit to interrogation. Although several members of his family were eventually tried and executed, Kaeppler himself refused the Guild order and escaped to the notorious Isle of Dread. Kaeppler built a stronghold there and is believed to have lived out the rest of his life as a hermit and researcher.