Inevitable Blood of Humans

Vampires have been integrated into society with humans for the most part they no longer feed off the blood of humans, but rather a special mix of genetically engineered and modified human blood. The 'crawlers' are a group of humans that kill vampires. Their activity is done in the shadows of society, because nowadays that activity is illegal, yes, vampires have rights under the letter of the law now.

Recently, vampire killings have been on the rise and at first glance the 'crawlers' are thought to be behind the murders. However, unlike in most instances, the 'crawlers' haven't claimed these killings, but because they don't mindless vampires they aren't saying they didn't either.

Behind the killings is from a new group of aliens. These aliens have secretly integrated into human society waiting for their time to strike. In a strange twist of events humans and vampires will band together to fight the aliens.