What's this lair/chateau/hall/crypt/castle thing?
It's a nonmoving building belonging to the named vampire. It's more a status symbol than anything else - the vampire in question has
donated at least $100, beyond donations for powers.
Other vampires can have homes of their own on a similar basis - though the donation required will increase the more often it happens, to make sure the city doesn't become consumed with owned buildings (current required donation for a building is $250).
Owned buildings may have an effect similar to that of Shadows upon their owner.
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