Creatures that kill, eat, and enslave people do not "peacefully co-exist" with humanity. The vampires of Carrion Crown are capital E Evil, and people are dying daily. No, they're not as big of a threat as the Whispering Way, but neither were the Skum/Mi-Go, and that shouldn't have stopped the heroes.
If people are being killed and enslaved, they're already at war with the vampires, whether they realize it or not. It's just one that they're losing.
