Board Thread:Midian Q&A/@comment-24302820-20150308084954/@comment-24302820-20160501194351

I may have opened a huge can of worms with the ecology bit.

While there's no way to know how many visitors come to Citadel each year--there wouldn't be such in the modern era, either--or even how many of those people vanish without a trace, we can still look at the effects of Vampire feeding on a stable populace. Vampires need about two pints of blood a day, as a sustainment level of intake.

Since the Vampires are A) taking blood from a visitor rather than a resident as a preference, B) taking blood from a body that may have died from means other than just exsanguination, and C) would prefer to not panic the populace above ground and alert those surface dwellers to the Vampire's true numbers, we can assume that most of the Vampires' diet is taken from victims who are slain and their blood distributed, rather than a little here and there from victims left living. Each of these victims then provides enough sustenance for about five Vampires per day.

This works out to about ten mysteriously vanished newcomers to Citadel, everyday, just for the original Vampire Cavalry. Even though Vampires can supplement their diet with animal blood, it's far less satisfying and 'nutritional'. Not only is a much greater quantity of animal blood needed, it's a bit like trying to survive off of just bread and water.

I'm not sure how the Malachim Embassy feeds. I vaguely recall it involving a large quantity of handwavium. I know exactly how it works for them back home, just not abroad.