Nighttime it's funny that it's always dark here. Living in a city that never see the sun, but that just makes it easier to get away with disreputable behavior.
And the shrouded City, sex and desire and wonderful sin walks around on every street corner. But be careful what you wish for, you'll get a lot more than what you ask.
Besides all that though the reasoning for the world being plunged into absolute the void. The reason what's a religious group that wanted to cleanse the world. But all they did was open up floodgates of demonic deviance to walk the earth. They summon something called Devil's gate, so after they did that every demon ,vampire, mummy, werewolf and mystical creature came out to play. And if that wasn't bad enough the sun disappeared. But the creatures of her Devil's gate and their leader, gave the world an alternative. Make the moon the new sun, by filling it up with demonic fireflies. The weird thing was the alternative worked , the downside though the demonic fireflies gave off a sinful energy.
So anyone who was outside too much would become uncharacteristically erotic. And then become a sexual deviant.
But the story doesn't begin there, we would have to go forward in time 500 years after Devil's gate opens. Let's start there shall we.