The Mayhews were old-fashioned sticks-in-the-mud who didn't move on with the times like everyone else. Dorian had heard that they refused to deal with humans at all in order to make their money so they developed some sort of unusual relationship with the witches to survive.
He hadn't liked that at all. Sharing a witch coven with them at all had been frustrating but knowing they likely favored the Mayhews over the Cromwells was too much to bear.
When one of his agents happened to run into a Mayhew out on an errand, he hadn't been able to resist the opportunity to get rid of those annoyances for good. Vampire lairs were extremely hard to locate because of the power of blood barriers, which hadn't been developed until the 1800s.
Once the blood pills replaced hunting, vampires had a lot more free time on their hands. Blood magic boomed after that because the efforts that had gone into hunting before went into research.
