Ghouls have always been one of my favourite D&D monsters. Partly its the imagery: crazed eyes, pale faces, fanged mouths, and long, long reaching arms are literally the stuff of nightmares. (Trevor Henderson has built an entire career out of them.) Mostly, though, it's the associations: hunger, madness, degeneration, desperation, loss. Those thin, emaciated bodies; those desperate, grabbing hands. Zombies are often cannibals too, of course, but they're mindless cannibals, whereas the point of ghouls is that they aren't mindless, which makes them much more horrible. There's a person in there, and all they can think about is just how much they want to eat you.
I started brainstorming some ghoul ideas recently and it got out of hand and I ended up with loads of them - so many I had to split them into two posts. Using them all in the same campaign would be massive overkill, but hopefully most readers will find one or two in there worth using in their own games!
1: Ancient ghouls. Certain ancient desert ruins are less abandoned than they appear to be, and by night the degenerate descendants of their original inhabitants come crawling up out of hidden vaults to kill and devour any who trespass in their ruinous domain. They speak a corrupted form of the original language of their people, although the skill of reading its hieroglyphs has long since been lost to them. They are adept at tunnelling into long-lost tombs, which they loot without compunction, convinced that they are the only true heirs of their long-vanished builders. They wield the rusted khopeshes of long-dead warriors, cram the rings of vanished kings onto their bony fingers, and wind the jewels of ancient queens in ropes around their withered necks.2: Anti-personnel ghouls. Barbarous traps devised by ingenious necromancers: ghouls are packed into iron coffins like sardines, which are then sealed shut and buried beneath the earth, their lids spring-loaded to open when a pressure plate is triggered or a lever is pulled. In a field mined with anti-personnel ghouls, one incautious footfall can bring mobs of mad and ravenous undead bursting to the surface to feast upon whomever triggered their trap. Some ancient necromantic battlegrounds are littered with hundreds of the things, still rusting away in the earth centuries after the battles they were originally deployed for. If retrieved intact they can be reused as traps, or even as unconventional catapult ammunition - hitting the ground should trigger the pressure plate, releasing the ghouls to devour everyone around the impact zone.
9: Chivalric ghouls. Huge, pale, hulking cannibals in rusted, bloodstained plate mail, their mad faces and monstrous fang-filled mouths hidden behind visors of tarnished steel that are forged in the shape of fantastical monsters and are never lifted except to allow the ghoul knights eat. They wield enormous swords and axes, hacking their enemies to bloody ruin and feasting on their remains. They are capable of more restraint than most ghouls, and could pass for 'just' a company of psychopathic super-heavy infantry until you see them feed. Happy to fight for any tyrant who can guarantee them a steady stream of victims.
12: Cyber ghouls. Recipients, willing or otherwise, of baroque and fantastical cybernetic grafts, whose machineries have been modified to run on flesh and blood. It is not their own hunger they seek to assuage but that of the machines bolted to their bodies, the ever-grumbling engines whose artificial stomachs break down animal tissue and convert it into the chemicals necessary to keep their malfunctioning machine-body interfaces running, at least for now. Fresh kills are cut up and fed, piece by piece, into the blood engines, where they are ground up by whirring metal teeth and prepared for chemical digestion. Common prosthetics include powerful spring-loaded legs, patchwork subdermal body armour, drug glands, pop-out metal claws, and stainless steel teeth. In an emergency the powerful digestive acids within the blood engine can be vented at attackers in a corrosive spray.