I've been thinking about a small family incest story... I know, not all that unusual, but what if the family were demonic?
What I had in mind involved a family of three, father, mother and a daughter. The father, an incubus and his loving, sex-starved family of succubi.
The general idea was to focus on the daughter, age 18, and the parents bringing her into her demonic power, then the process of training/teaching her how to use said powers without killing a hapless mortal or revealing herself to the mortal world as she learns to hunt and live in a world that's full of tasty snacks that would be very happy to kill her.
Additional roles might be possible, and expanding the story is likely as things progress, but I foresee the parents being hard pressed to keep their child under control before she does something unfortunate while they also try to feed, have gratious amounts of sex and maintain the vail over the family.
In my mind, as a natural life-preserving feature of their demonic natures, the young are protected from discovery and destruction by the simple fact that they don't have access to their power and look very human until the first full moon after their 18th year. There are two ways to come into their power at that point; guided, and unguided. The guides are usually a parent, or two, who protect and teach until the new demon is able to hunt and survive on it's own without giving itself away. The unguided way usually results in someone's death... either a mortal or the demon after being discovered because it doesn't know how to conceal itself. Not always, but fairly regularly.
So... I'll play whatever role is left open, but I'm looking for someone to fill one of the three roles... actually, two someones.