Consumption of the Hampires
Granny Which Witch's original whopper as related to the author by the groom.
Some people are more than they seem. Some are much worse. Some people are exactly as they appear, and they're often the worst sort.
The groomsman is convinced to lead a rabble in arms to throw off the shackles of vampiric tyranny. All goes better than expected until he is appointed to find new royalty to replace them.