This Present Darkness
Rite of Tranquility
Those mages who are too weak of will to resist demonic possession or appear to be dangerous are forced to go through the Rite of Tranquility (and become one of the Tranquil), which (involving the use of a magical brand made of lyrium) cuts off a mage’s connection to the Fade – they can no longer dream. As a side effect, their emotional center is utterly removed. One or both of these things make it so that demons can no longer possess them (it’s not certain which). In the mind of one of the Tranquil, there is no passion. They keep to themselves, and, if asked directly, will readily agree that having the opportunity to live out a peaceful and useful existence is far preferable when compared to what their alternatives would have been.