My interpretation of whatever monster I feel like talking about, primarily from the 1st ed AD&D Monster Manual and Fiend Folio, but not limited to them, treated in a way that deals with the stuff I find interesting. That is: ecology and culture, if applicable. Stats can go hang.
If you say it quick and move on to the combat, a Ghoul seems straight forward. But if you break down the characteristics logically the Ghoul is an unlikely and strangely hard to classify creature.
1) It eats the flesh of the dead. Well, so do all meat eaters. No, we mean it eats the flesh of dead humans (allowing that it is also human). So it’s a cannibal? Well yes, but no. That’s not the point. It does not attack living people, kill them and eat them. It exhumes the corpses of recently deceased humans and eats that partially decayed flesh.
2) It is undead. Like a Vampire? Not really. Vampires (classical Vampires, not misunderstood teenagers that sparkle in sunlight) have been granted immortality by Satan, the cost of which is the need to consume the living blood of humans (typically virgins of the opposite sex – look it up. This is the real story and meaning). So like a zombie, then? Again, not really. There are three kinds of zombie: the genuine traditional zombie made mindless though drugs who probably only need turnip soup to keep vital, the undead zombie raised through necromantic spells that don’t need to consume anything at all, and the disease-spawn zombie that barge around taking bites out of people for no adequately explained reason.
3) It hangs around graveyards and tombs. Like black-wearing, tattooed and body-pierced goth kids that are so rebellious and feel the call of darkness? Possibly.
So what is the Ghoul?
The Ghoul is the lowest and most pathetic of the demonically corrupted humans. Lacking in either native intelligence or inherent drive, their conversion to the worship of forces of Darkness has led them to the lowest rung of Earthly reward. Their immortality is bought at a disgusting price. Their life force has been drained by the dark powers, leaving them emaciated and incapable of surviving sunlight.
Being inherently pathetic they are not up to the level of sophistication of the Vampire. Instead, they suck what little life force remains from the corpses found in graveyards. This meagre energy source is scarcely enough to sustain them and so they appear weak, diseased, waxen-skinned and repulsive.
More energetic and imaginative ghouls stalk the battlefields, creeping through the trenches, strangling and then feasting on the mortally wounded. But these types are rare. The more common Ghoul cowers in crudely dug tunnels under the crypts and grave, tunnelling up and guzzling the putrescence that drips.
A Ghoul, if encountered, is a cringing, craven, strenchous monstrosity. It will beg and weep and beg for mercy. Never attacking openly, if confronted it will submit in the most contemptible fashion.
But never turn your back on one.
No, never. They cannot be negotiated with in good faith. They cannot be redeemed. They cannot repent. All their protestations are a front. If they can they will garrotte you in the blink of an eye. Then drag your corpse to a quiet spot where it can mature and bloat for a few weeks…