Despite common myth, Vampires are not undead, and they do not propagate by biting. In fact, the 'curse' of vampirism is entirely hereditary.
Vampires are not relieved of a need for food and water, but can subsist largely on humanoid blood. Vampires benefit from greater magical aptitude, and a slightly greater resistance to the toxic effects of Mana. They easily learn new spells, and cast known ones with greater efficiency and power.
The desire for blood is variable from vampire to vampire, with the severity of the 'curse' being dependent largely on the curse present in their ancestors. It's uncommon that humanoids are bitten anymore, as animal blood is as effective for feeding the vampiric vice as any other. However, their mostly obscured history has led to persecution by many, forcing them into staying put on their native sphere. Due to the lack of incidents, everyone is quite sure they are scattered to more far flung spheres where they've already withered. However, due to Garude's fierce laws about conflict within city's limits, they actually have stayed put for the most part.
Most rumors about vampires are untrue; things like garlic, religious symbols, and sunlight do not affect them. Vampires do not suffer under the sun's rays, though are often rumored to due to their nocturnal lifestyles.