Well, supposedly the villagers getting picked off (not just the 2 in the barracks) is cause-and-effect to the forest getting cleared and the vampire's choosing a carnivore as their livestock.
They should have learned animal husbandry and tamed forest dwelling herbivores, but the vampires are "isekai-handicapped" too.
@Amaterasu93 As for "Lawful," you could say that her being able to read and write as well as outright telling MC that she's the daughter of the vampire chieftain would place her as "foreign invader" and falls under a non-local rule set. From that, the contract to not eat the townsfolk acts as a written "treaty."