"It is fashioned from the alchemically transmuted blood of an angel or demon, given willingly. In Flamel’s case, unquestionably that of an angel. He draws upon his patron’s lifeforce to extend his own short span of natural years to partake of that of an angel’s. Without it, he will grow old and die as other mortals do, and our enemies will have lost a rare ally among the wizards and witches."