A Sourdre de Sang ("Fountain of Blood") is the title of a master vampire who is powerful enough to be a master, or head, of their very own line of vampires. A sourdre de sang generates his or her own animating power, and also provides animating power for all vampires that share its bloodline or have taken blood oaths to members of the sourdre de sang's bloodline. A sourdre de sang is owed a duty of fealty by all vampires that draw power from their bloodline. The ability is rare enough that hundreds of years can pass by without any vampire gaining enough power to become a new sourdre de sang.
The most notable sourdre de sang are certain members of the Vampire Council. It is not required to be within the council to be a sourdre de sang nor is it required that a vampire be a sourdre de sang to be a council member, although, it is more than likely the vampire will not last long as a Council member if he or she is not powerful enough to have their own line.