The Mind Wizards are bastards, but the Death Sorcerers are cruel beyond words. Having made a pact with an avatar of Death, they comb the lands raising armies of undead and demanding the sacrifice of the young and nubile. Where the Mind Wizards play at subtlety until they have achieved power, a Death Sorcerer comes on strong and brutal and doesn't stop until utterly eradicated.
It isn't known if each Death Sorcerer is part of a greater cult as they have only ever (thankfully) been encountered as individuals. Perhaps they don't get along, perhaps their attacks are some form of initiation, or perhaps they truly are individuals that have all made the same vile necromantic pact. The one thing that everyone knows for certain is that every known Death Sorcerer is female of incredibly physical beauty.
When they aren't out digging through worm-infested graves searching for the next corpse to raise as part of a freakish mount or attempting to bind the spirit of a demon to the rotting flesh of a giant, Death Sorcerers are want to wander through towns seducing fools to join their ranks of worshipers. It is whispered that they are wearing the animated flesh of a local victim to blend into the population until they unleash hell. Rumors also say that they explode in a shower of maggots when a death blow is struck, so the truth may be unknowable.
It is said that the bite of a ratkin can bring about a state most reviled in humans: an infection of arourcanthropy - the target becomes a wererat. The wererat retains some aspect of it's former self and can wander in human society. From there the Ratkin can hatch and spread even more devastating plans. The wererat isn't long lived, though, as the chaos and darkness of the dungeon eat away at his brain. In less than a season the creature become raving mad and forever be little more than a beast.
Goblins & Their Filthy Ilk
The Goblin King sits in his dark and grimy hall, the oily smoke of roasting flesh commingling with the stink of excrement of all manner. He snorts and waves a hand for the new batch of children to be brought forth. Most are screaming toddlers, a few are babies, and fewer still are old enough that can truly take in the horror of what is happening. The Goblin King inspects each one and spits into their mouth, beginning the transformation.
Goblins were once human children that were stolen by the minions of the goblin king. Most hold on to some vestige of their former life - a scrap of blanket, the arm from a stuffed doll, or simply some nursery rhyme that plays over and over in their head. Goblins are mad creatures to the last one - given up to the Dungeons by the Goblin King or unfortunates, even by goblin standards, that wandered into the Underworld never to find their way home.
Some goblins are allowed to age and grow into brutish hobgoblins. Rumors that orcs and bugbear are also related to the Goblin Kingdom surface from time to time, but there is no way to prove or disprove this. Goblins are the lowest of the humanoid totem pole. While kobold are found enslaved from time to time, goblins serve willingly and put up with far more abuse. They are sad creatures that are deserving of some pity ... right up until they shove a thin hand-worked shard of pottery into your side and laugh while humping your arm. Goblins are truly corrupt and vile things to be put out of their and our misery.
Of all the monsters that roam the lands, one word strikes fear into every man: Troll. No matter what the terrain there are trolls that inhabit the land. They are large, fast, and strong. Thankfully, they are also dim-witted and tend to follow particular behaviors (or at lest that is the common belief) and are more or less rare creatures.
Trolls don't like the sunlight - it tends to cause them great discomfort and turn them to stone. They are particularly fearful of fire and acid because those wounds don't regenerate, just heal (t is a well known fact that trolls regenerate at an astounding rate.) Everything else about a troll is going to come down to where they live - trolls (like dragons) tend to absorb some of the traits of the land which they inhabit.
Cave trolls are shaggy and blind, swamp trolls are thin and green with with rubbery hide, forest trolls are tall, slender, and tend to grow additional heads with age. Mountain trolls ... well ... mountain trolls are creatures that grow to such astounding size that an encounter up close will surely end in death. No matter what the species, though, all trolls heed the call of the dungeon - it is inside of them always. The hollow stare of a troll is looking down an infinite black corridor in the underworld itself.
The Faceless are a religious sect that believe in the shedding of individuality to purge one's soul of desire. That and the letting of blood to feed their unspeakable demon lord. At first glance the faceless are simply humans wearing heavy cloaks with strange mirrored face masks. If that mask is removed, however, something more sinister is discovered - they are no longer human and truly have no face. No eyes, ears, mouth, or nose - just a series of tubes that snake through their system and into their face, connected to the mask and the cloaks they wear.
In addition to being seemingly impossible to strike (they dodge with tremendous skill and seem to shirk off even the most potent of blows) the faceless carry an array of weaponry that is strange and alien - metal rods that vomit lightning, the sun enraged and captured in small ceramic bottles, and magic that brings the earth itself to life to grab and pierce and hurl targets to the ground.
The faceless tend to keep to themselves on their strange pilgrimages. What they want and from whence they come is unknown. How to defeat them when they attack is often discussed but few true facts are known. Their inexplicable connection with the Underworld Elves is tenuous but exists. How to react when encountering them is a mystery.
If you see a Faceless, run. If you must fight them, pray to whatever gods you believe in.