The surviving heroes may have a potential defense against the vampires in the works, but it might make things even worse.
The following article contains spoilers from DC vs. Vampires #7, on sale now.
The surviving heroes of the vampiric takeover may have discovered a secret weapon. DC vs. Vampires #7 (by Matthew Rosenberg, James Tynion IV, Otto Schmidt, and Tom Napolitano) revealed that Harley Quinn successfully made it to Kandor, the last human sanctuary. Those who have been following this alternate story know that Harley injected herself with Lex Luthor’s blood, making feeding off her deadly to vampires.
It’s a potential vaccine against the vampire army, one that could be reproduced if placed in the right hands. While this may seem like a secret weapon for humanity there is one potential downside to it. If the humans manage to find a way to mass produce its effects for everyone, they become impossible for vampires to feed off of. If their food supply is gone, there would be nothing to hold the vampires back from destroying humanity as one final act of revenge.
The reality is, humanity is on the brink. The only reason larger groups of humans survived is that Nightwing recognizes that vampires need humans. Not for any normal reasons such as kinship or even a shared origin, but because the vampires need food. There must exist a balance between humans and their vampire overlords, if only to feed the vampire population. That parasitic need has kept humanity alive, but if the heroes manage to spread out this “vaccine” then they’d be cutting off the vampires’ entire food supply.
The logical next step would be to attack hard and fast, using the vampires’ weakened state to retake control of the Earth, but they would still need to wait a bit before it came to that. If nothing else, Nightwing has proved that he is a shrewd leader. He would probably have blood stockpiles hidden somewhere in the event of a shortage, but even that will run out without a steady human blood supply to drain. He might realize that though, and decide on a more brutal course of action.
This story has shown that vampires have no hesitance about savagery. When they were turned what made them human was gone, only their darkest urges remained. With no food supply and no hope for the vampire kingdom, Nightwing might simply act out of spite, ordering that the vampires of the world kill ever human they can find. There would be no point to said massacre beyond pettiness, an attempted mass murder-suicide. If the vampires can’t live, then the humans will be dragged down with them.
It’s a terrifying thought, and one that’s all too possible in this world. It’s only made more likely considering the state of the survivors. They don’t have enough resources to effectively wage a war against the vampires. They have to argue endlessly just to decide what mission to commit all their resources to. If the vampires decide to initiate a true genocide as a response to humans becoming impossible to feed on, then the last remnants of humanity wouldn’t stand a chance.