Vampires? Where are they from? (UPDATED)

Multiple Crossovers such as: (Gravity Falls, Codename KND, Ed, Edd, n Eddy, A Goofy/Extremely Goofy Movie, Regular show, Hey Arnold, South Park, and some OC's, but in a very different dimension) Vampires are trying to take over this place. People are getting attacked and transformed into these creatures. Whose is gonna survive this Vampire Crisis?