The vampire population had increased gradually over the centuries. Eventually, vampires proved to be the “superior” species and quickly dominated the Earth over humans.

Vampires, although being very territorial, were practically better than humans in every way imaginable. As such, vampires found a way to deal with the lesser beings.

Human breeding grounds were made to keep a constant supply of blood. And if a vampire wished, they could take a human as a “pet”. Which is what you are.