Darkness in the City of Light

In the year 2090, almost all illnesses were cured. With the development of new technology, the only diseases left are airborne, but mostly everyone is immune to them. But that same year, infants were born with a strange birthmark; always on a shoulder and always in the shape of a star. No less than 15 years later, strange beasts the size of horses started appearing. Like wolves they hunted in packs, but had scales of armor like rhinos, long tails like lizards, huge claws like the dragons out of myths and legend. And like vampires, they feared the light and feasted on the blood of humans, leaving their dry corpses to be discovered by friends and family. The year is now 2113, and with more and more of these creatures roaming cities, the people fear the human race will soon go extinct.
These creatures have been dubbed Dark Demons, and the remaining humans are called Lights. What was once New York is now the City of Light; but only half belongs to the people. The other half has been overpowered and overrun by Darks. With nearly all the lamplights broken, they roam at their own leisure, claiming any life that dares to enter their territory.