[quote=ShadowWolf]
Could there be mystical beings involved like vampires, hybrids, etc?
[/quote]

No. If there was, it would be [i]extremely[/i] limited. If I were to allow it, then there would be restrictions placed on them. 

One idea for a restriction would be that all mystical beings had been captured by a powerful corporation and are being held in isolation as scientists run tests on them without knowledge of outsiders and once in a while, for testing purposes, the beings are let loose in the streets to see if they can live normally among humans.