Blood Magic
Perhaps you learned magic from a particularly dark cult. Maybe your spirit needs additional energy, beyond your strength of will, to enact magic. Perhaps you foolishly studied under a vampire or tomes plundered from vampires. Whatever the reason, your sorcerer's use of magic always requires the sacrifice of his own blood. In some cases, it will simply burn away from inside. In others, the magician must cut himself and include it in the ritual. Each use of magic causes an unsoakable level of bashing damage. Furthermore, the Resonance of your magic is likely to be dark, or at the very least, martyred in nature.
Source: Mage the Ascension - Sorcerer Revised - pg.56
