There is so much to say about those who drink blood, so many articles, so much history! Suffice it to say this group of Vampires feed on blood. The belief of this group is that they require something in the blood to keep them healthy. Without blood Sangs tend to become depressed, apathetic, they become ill when their immune system breaks down, leading to lethargy, illness and sometimes even suicidal tendencies. For these Vampires blood is not for play. They physically need it.
The links below offer basic information on this group of Vampires.