The (More Than) Complete Cast of CVRPG
Heroes, Villains, Low-lives, and Agents of Leisure
Although the succubi and incubi are afamed, fabled race, it's rare to actually see one in the flesh. As being of the dream world, the dream demons (as they're collectively known) spend most of their time floating astrally through the minds of their victims, finding those that are alspee and feeding on their sexual thoughts.
The Succubus (not just a succubus but the Succubus) used to be one among the many, but she found a taste for the physical world. Steping through the etherial plane, she found the joys to be had in feeding on the joys of the bedroom. Lust and sex and sweat and all that good stuff that happens behind closed doors (or in a park, or the back of a Volkswagon if that's your thing) became like a drug to her, and she craved more.
To exist in the physical plane, though, makes one a slave to the needs of the physical world -- not just sex but food, shelter, and sleep are all required. these were things the Succubus never had to worry about before, but the matters became all too pressing all too quickly (it's amazing how quickly a physical body craves a shower and a bit of respite on the toilet). To take care of these matters, in the end, required money. Money to buy food, money to rent shelter. Money.
Thankfully for the Succubus a job was just waiting for her -- a job at Dracula's castle. Seizing an opportunity when it's presented, the Succubus quickly joined up with Dracula's bad of merry minions (working title), and the rest has been history.
While many a succubi has worked for Dracula (you should see the horde that populates Carmilla's abode), the Succubus is a special case. Having joined of her own free will, the Succubus is a bit of a free agent, able to come and go as she pleases, when she pleases.
Part of this is by necessity -- the Succubus feeds on the dreams and desires of mortals, a sexy thought vampire that lurks late at night. While the creates that populate Dracula's castle may have dreams and desires, few provide the kind of sustenence the Succubus needs (and fewer still are desireable bu the Succubus, which is kind of arequirement for her).
And so she leaves when she wants, comes back when she wants... and when a battle looks like it's going to turn against her, more often than not the Succubus takes her leave -- she's a being of the dream world, and the dreams are just a quick step away whenever she wants.