Vampires (classified Type 1 by CenSSA, classified Type 2 by the Department of Domestic Defence) are a post-human supernatural species which are cursed with a constant craving to kill and drink the blood of humans. Some vampires choose to fight this urge and avoid feeding, but the majority choose to kill and feed as they please. Vampirism is passed on by a process known as recruiting, which involves a bitten/dying human drinking a vampire's blood. When this happens, the person becomes immortal and cannot die naturally, however he or she will be cursed with a constant thirst for human blood. Normally, vampires are indistinguishable from humans; but when thirsty or showing aggression, fangs appear in place of their canines and their eyes turn completely black.