The Crowley twins, Michael and [BLANK (female)], are the demonic agents of the demon Lilith, Queen of Lust. The night of their fifteenth birthday they were kidnapped by Lilithís Earthly cult and their souls were maimed, drugged with Lilith Root extract and sent in to a lust filled haze where brother and sister no longer mattered. As the two climaxed, Michael in his sister, the energy that was released at the rending of their human souls summoned Lilith. The twins, still under the effect of the extract, readily bedded with Lilith, and she planted in both of them the seeds of demonic power, to be wielded when they turned 18.
Their memories were wiped of the event, and their blood mother was killed by the Cultists to force the twins in to the Orphanage system. They were quickly adopted by a young, rich, single woman, secretly a servant of Lilith and her cult.
The twins kept to themselves, and never left each otherís side. It was an odd site, seeing two siblings act so intimate with each other, but it wasnít unnecessarily strange. They moved around often over the next three years, before settling down in New Jerusalem, California. That was where the twins turned 18, and their demonic souls were unleashed.
Lilith visited them that night, bestowing knowledge and power unto them, as well as orders to gather followers to Luciferís cause however they saw fit. Their powers would be subtle at first, slowly growing as more and more lust filled New Jerusalem. The twins, filled with power and lust, began to lay the groundwork for their plans.
This idea is supposed to be rather filled with debaucheries and taboos (No hard BDSM, gore or watersports or scat, but Futa, Impreg, and other kinks would be present). The twins would take part in incestuous acts often, with each other and their adopted mother, and also bringing others to break the taboos of incest (getting a teenager to seduce and fuck her father, etc.) and other things.
The major conflict would arise from a sect of Scions of the Angel Balthazar who begin to investigate the growing taint spreading in New Jerusalem, and the Crowley twins would need to fight them off, but quietly, or else face the wrath of the Host of Heaven.
For the kind of rituals, corruption, and other such debaucheries, anyone familiar with the game/OAV Bible Black would have a basic idea.
Anyone showing any interest, post here! Obviously, you would be playing the female twin, but other characters can be included at any time.