I am running the Curse of Strahd campaign, for 5e Dungeons & Dragons.
Kasimir has taken the dark gift to become immortal, and has killed his closest friend, drinking his blood, becoming a vampire. While the players are away (they do not know he is a vampire), I would love him to seize control of Vallaki. (The burgomaster is already dead, and Lady Wachter was, with her cultists, in a sort of control over the town.)
I would very much like the characters to come back to the town controlled by Kasimir, with Lady Wachter held captive as his prize.
The question is, how long would it logically take for him to be able to do this?
I guess a logical subquestion would be, how many vampire spawn can a new vampire create each night?
How long do you need it to take?
... and what do you mean by "take over"?
As to the corollary question: the absolute maximum is 14,400 every 24 hours (24 hours x 60 minutes/hour x 10 rounds/minute = 14,400) assuming the vampire has enough willing workers to bury all the corpses. Practical considerations like moving between victims, dealing with non-helpless victims and wear and tear on the fangs suggest that the actual number would be much lower.