[split] Vampires and Vampirism

[fool-ish]

It would seem that vampirism and such things in the "Anita blake" series is of the mago-genetic type.
It is clearly based in genetics, yet it is also magical. One interesting trait that has been brought along from the common vampire mythos is the presence of human "servants". Some aspects of the mythos make vampire servants mere mortals, suppressed, serving willingly (or not), often having no choice in the matter. Others have servants being sort of "lesser" vampires, or even "vampires-to-be", that the servants eventually become vampires themselves.
In the world here, the servants get literal advantages like increased healing, disease resistance and such from the "bond" with a vampire.

The power of Vampires is also somewhat more realistic here, not purely based on age, but with age a major factor. Some vampires become powerful quickly, others more slowly, and some don't gain power beyond a certain point ever.

If they are vampires through genetics and magic, then it would seem there is no requirement for blood letting? Is blood still essential to their existence? I shan't be happy if magic alone keeps them going, it's just not right!