As ghoul feeding habits came up a thread (http://www.yog-sotho...dying-relative/), I thought they would deserve a thread of their own for discussing their nature, feeding habits, etc. You name it.
Similarly to other monsters based on folklore, there are several, often conflicting views. I guess instead of folklore, the baseline should be set by H. P. Lovecraft. This is what Wikipedia says:
In the fiction of H. P. Lovecraft, a ghoul is a member of a nocturnal subterranean race. Some ghouls were once human, but a diet of human corpses, and perhaps the tutelage of proper ghouls, mutated them into horrific bestial humanoids. In the short story "Pickman's Model" (1926), they are unutterably terrible monsters; however, in his later novella The Dream-Quest of Unknown Kadath (1926), the ghouls are somewhat less disturbing, even comical at times, and both helpful and loyal to the protagonist. Richard Upton Pickman, a noteworthy Boston painter who disappeared mysteriously in "Pickman's Model", appears as a ghoul himself in Dream-Quest. Similar themes appear in "The Lurking Fear" (1922) and "The Rats in the Walls" (1924), both of which posit the existence of subterranean clans of degenerate, retrogressive cannibals or carrion-eating humans.
According to "Pickman's Model", ghouls "approach humanity in varying degree" and "while roughly bipedal, had a forward slumping, and a vaguely canine cast" and had a rubbery skin. "The Lurking Fear" has a slightly different take: "they were dwarfed, deformed hairy devils or apes — monstrous and diabolic caricatures of the monkey tribe". Also, yellow fangs and matted fur are mentioned. Of course, it's not fully clear if the things in "The Lurking Fear" are indeed ghouls. "The Rats in the Walls" describes degenerate men's, or possibly ghouls' remains: "skulls denoted nothing short of utter idiocy, cretinism, or primitive semi-apedom". I guess with ghouls' appearance, the canon route is to choose the "Pickman's Model" description, perhaps with some likeness to apes.
In HPL's works, ghouls are described to eat humans: both buried corpses and recently slain. If "The Lurking Fear" describes ghouls, they are also cannibals. Of course, it doesn't say anywhere that they would eat solely human or ghoul flesh - unless there is a ritualistic or supernatural reason for doing so, I'd guess they eat animals as well.
The subject of supernatural brings us to the next question: are ghouls supernatural? If they are, what is their origin? Are they some sort of degenerate humans, somehow cursed or transformed to become ghouls? In "Pickman's Model", changelings (and the possibility of Pickman being one) are mentioned. Do ghouls actually procreate and for some reason (suggestions?) switch babies? Or do they just steal human babies for turning them into ghouls? Perhaps they have a problem of overpopulation and the whole changeling scheme is to get rid of one mouth to feed and at the same time, get a delicious human baby to feast on in return? Speaking of population: do ghouls die of old age? In a lot of folklore (and fantasy RPGs), ghouls are undead. Maybe they're somewhere in between mortal and immortal/undead, having to replenish their life essence by eating corpses/bodies of sentient beings? While eating animals may feed their hunger, going longer periods without munching on some juicy humans will cause a ghoul to age, or if it's already past its "natural" lifespan, decompose...
And while on the subject of supernatural: what powers and/or weaknesses do ghouls have? They're possibly undead or immortal. They see in the dark - but do they suffer from sunlight? Can they see in bright light at all? Does sunlight injure or even kill them? In some folklore, ghouls have powers such as turning into a hyena, or appearing as the last person they've eaten. While shapeshifting to a hyena doesn't sound very Call of Cthulhu to me, ghoulish versions of Pose Mundane and Consume Likeness spells sound reasonable. What about turning a person into a ghoul? I think the "victim" should be willing, and the ritual would involve him/her eating carcasses - perhaps progress from animals to humans and finally taste ghoul flesh to complete the "sacrament of flesh" and become a ghoul. I also had the idea, that the ghoul that "sires" another this way (perhaps the ghoul flesh eaten has to be his) holds some degree of power over the newly transformed ghoul. Maybe a form of Mental Suggestion, that can be cast in 1 round and/or doesn't require overcoming MPs, possibly costs less MPs than the spell.