In Dungeons & Dragons, you come across a lot of monsters. The Monster Manual alone has about 350 pages, with an average of over one stat block per page. Add on Mordenkainen’s Monsters of the Multiverse, at 250 pages, and all of the other books, many with monsters specific to those settings, adventures, areas, etc. There are a lot of monsters.
If you try to explain Vanilla Fantasy to someone, often times you’ll use the word Medieval, as the basis of the game is the Knight fighting a Dragon to save the Princess. However, a lot of monster designs aren’t actually based on the classically Medieval belief system, as they were primarily all metaphors for a lesson in the Christian faith.
Well, I found a website called The Medieval Bestiary that has collected dozens of Medieval beliefs about various creatures. I went through every one, and brought what I thought would be helpful in a D&D design concept. This site is amazing, and deserves a ton of credit, as I am just piggybacking off their hard work. They also update it on a regular basis as new manuscripts are found, and you can find updates at Bestiary.ca/chimaera.
Many of these are very strange, as I realized that a lot of design we have today is based on a wide range of mythology, specifically GrecoRoman, not Medieval Western European. While you can keep these weird attributes on the animals they were originally told about, these are also just interesting aspects that you can put on any monster that you feel is a bit bland.
There are 3 types of helpful ideas on this list. Alchemical, things that might help with magic potions or chemical affects, Monster Concepts, from regular creatures that they believed were more magical than they were, and Magical Monsters, things that just don’t exist.
Bear They can safely eat the apples of a Mandrake if they also eat ants. Also, the herb phlome (the innermost layer of tree bark) or mullein are healing herbs.
Diamond If a diamond is kept in a house, no harm can come to it, not even demons cannot enter. A person who possesses a diamond can overcome both men and beasts.
Duck Their blood is useful as an ingredient in antidotes to poison
Elephant If the skin or bones of an elephant are burned, the smoke will drive out serpents.
Fire Stones Stones that burst into flames when brought close together
Goat The blood of a goat can dissolve diamond.
Hedgehog A cooked hedgehog can be used to make medicine.
Indian Stone Can cure Dropsy, swelling due to heart failure
Lion A sick lion cures itself by eating an ape
Lynx Spotted wolf (it’s actually a cat), Its urine hardens into a precious stone that is flame colored and similar to a carbuncle. The lynx covers its urine with sand so that humans cannot find the stone.
Ostrich Can digest anything, even iron
Oxen The dung cures the bite of a water snake called Hydros
Pearl-oyster Drinking pearl tea will cure any disease.
Pelican A bird that revives its dead young with its own blood.
Snakes When they begin to lose their sight, they can eat Fennel to regain it
Stag A drink made from the tears and the heart bones of a stag is a cure for troubles of the heart. Some say that the stag cures its ills by eating crabs it finds in the water. When stags are struck by arrows, they can shake them off by eating Dittany. People who eat venison are protected from fever because stags are never feverish. The smoke from burning stag antlers is deadly to snakes.
Wolf At the tip of a wolf’s tail is a tuft of hair that can be used for love potions; if the wolf is about to be captured, it bites off the tuft so that no man can get it.
Ape They birth two young, one they love and one they hate. In the original, when they are being chased they end up dropping the one they love, but that can be adapted to dropping the one they hate.
Asp A snake with a ruby/garnet in its head.
Badger When building tunnels, a badger will lay on it’s back, and hold a strong stick in their mouth. Then the others will pile earth onto the first’s belly, and pull them out with the stick.
Use Giant Badgers with Dwarves to dig tunnels?
Bear The cubs are born unformed, and must be licked into shape by the mother. Perhaps a bear cub can be captured and used to be molded into a different animal, depending on what creature you give the cub to.
Beaver Hunted for its testicles, it castrates itself to escape from the hunter
Bees Born from the bodies of dead oxen, worms form in the flesh and turn into bees.
Cool that once you kill a beast, an insect swarm suddenly emerges it’s body.
Bull A hide so hard it rejects spears (piercing damage).
Good for special leather armor, but hard to skin.
Crocodile Its skin is very hard, so that it is not hurt when struck by stones (bludgeoning damage).
Crow Able to reveal ambushes and foretell the future
Cuckoo Their saliva produces the insect known as cicada
A creature that spawns another creature during battle.
Echeneis Clings to ships and delays their passage, where even the high winds of a storm the ship will not move
Elephant If a female gives birth on land, the elephant’s enemy, the Dragon, would devour the baby. To make sure the Dragon cannot attack, the male elephant stands guard and tramples the Dragon if it approaches the pool. If by chance they see a man wandering in the desert, they offer to lead him to familiar paths. Elephants were used to carry a platform or carriage called a howdah, which could sometimes be quite large and elaborate.
Hoopoe If the blood of the Hoopoe is rubbed on a sleeping man, devils will try to strangle him
Horse Can smell war
Hyena There is a stone in the hyena’s eye (some say in the stomach of its young) that will give a person the ability to predict the future if the stone is placed under the person’s tongue.
Ibex A goat with horns so strong, that if it falls and lands on the horns, it will be unharmed.
Kingfisher When these birds lay eggs on the shore, there will be no storm for the 14 days it takes to hatch/nourish them, even though it’s during the rainy season.
Lion The lioness give birth to five cubs the first year, then four the next, and three the next, until after the birth of a single cub in the fifth year, she becomes barren and has no more cubs. Her cubs are born dead and are brought to life on the third day when the mother breathes in their faces or the father roars over them.
Mole Its hearing is so acute that it cannot be taken by surprise.
Onager Wild Ass that brays 12 times on March 25 to signal the Spring Equinox
Oxen can predict the weather
Panther Only enemy is the dragon, who is afraid of the Panther
Parandrus Size of an ox, head of a stag (maybe just a reindeer), and can camouflage itself into it’s surroundings
Salamander So cold they can extinguish any fire. If it enters hot water, the water will become cold. They can create a material that, when dirty, must be thrown into a fire to be cleaned. If a Salamander climbs an apple tree, or enters a well, the it will poison the apples/well.
Torpedo A fish that, if touched, makes one’s body stiff, and numbs even the strongest arms and paralyzes the swiftest feet. Actually just an Electric Ray.
Vulture Can predict the number that will die in battle, and can therefore predict an ambush
Weasel The weasel is the enemy of the Basilisk and is the only animal that can kill one.
Wolf If a wolf sees a man before the man sees the wolf, the man will lose his voice. If the man sees the wolf first, the wolf can no longer be fierce. If a man loses his voice because the wolf saw him first, he should take off all his clothes and bang two rocks together, which will keep the wolf from attacking.
Alerion Like an Eagle, but with wing as sharp as a razor. Only 2 in the world
Amphisbaena A serpent with two heads, one at either end,
Basilisk Rooster with a snake’s tail. Odor that can kill snakes. Fire breathing, glance will kill a man. Only the weasel can kill a basilisk.
Bonnacon A beast like a bull, that uses its dung as a weapon, which can travel as far as 2 acres and burns anything it touches.
Classic toilet humor
Caladrius A bird which can tell if a sick man will die, and can cure disease, by drawing the sickness into itself, and flies up toward the sun, where the disease is burned up and destroyed
Catoblepas A beast with a head so heavy it can only look down. It has a long mane that hangs over its eyes, which are red and bloodshot. If the beast were ever to look up it would be deadly, because anyone who looks into its eyes will die immediately. It also has a foul and dangerous breath from eating poisonous plants.
Centaur A beast part man and part horse
Dragon Lashing tail does more harm than it’s teeth. Enemy of the Elephant, kills them with suffocation. Venom is harmless. When menaced by a dragon, doves will fly to a Peridexion tree, where they are safe, for it repels dragons.
Griffin A beast with the body of a lion and the wings and head of an eagle. Enemy of the horse. A griffin will tear a man to pieces or carry him to its nest to feed its young. Griffins are strong enough to carry away an entire live ox. They are also known for digging gold from mines.
Harpy Fierce bird with a human head, personification of storm winds
Hercinia Their feathers glow so brightly in the dark that they light up the path, and serve as a beacon for travellers
Hydra Has multiple heads. If one is cut off, two more will grow in its place.
Hydrus Slides into the mouth of a crocodile to kill it
Ichneumon Slides into the mouth of a dragon to kill it.
Jaculus Flying serpent
Leontophone To kill a lion, the flesh of a leontophone is burned and its ashes are sprinkled on meat, which is placed at a crossroad; if a lion eats only a small amount it dies. Lions hate leontophones and hunt and kill them, tearing them apart with their claws rather than biting them.
Leucrota the same size as an ass, but with a horse’s head, chest and legs like a lion, hind quarters like a stag, and cloven hoofs. It has an extremely wide mouth, that stretches from one ear to the other. It does not have individual teeth, but only a single bone where teeth should be. Like the hyena, the leucrota can make sounds that resemble human speech.
Mandrake Shrieks when pulled from the ground, great use in medicine, but anyone who hears the plant’s cry dies or goes mad. It was therefore a custom to tie a hungry dog to the plant by a cord and place a piece of meat beyond its reach. To get at the meat the dog tugged at the cord and dragged up the plant, while its master remained safely out of hearing.
Manticore blood-colored lion’s body, the face of a man with blue eyes, and a tail resembling the sting of a scorpion. Its voice is a whistle that sounds like a melody from pipes. Some say it can shoot spines from its tail.
Mermaid Half human, half fish
Monocerus the head of a stag, the body of a horse, the feet of an elephant, the tail of a boar, and a single very long black horn growing from the forehead. It is the enemy of the elephant and when fighting it aims its horn at the belly of its opponent.
Muscaliet the body of a hare, legs and tail of a squirrel, teeth of a boar, ears of a weasel, muzzle of a mole, hair like a pig
Onocentaur upper body of a man and the lower body of an ass
Phoenix A bird that rises anew from the ashes of its own funeral pyre. There is only one living phoenix in the world at any time.
Satyr Ape-like wild man that often carry a club.
Very different from the Greco-Roman Satyr
Scitalis Serpent with markings on its back are so marvelous that it stuns the viewer, slowing the person down
Siren A deadly creature, half human, half bird or fish. They usually have wings. Sirens charm men with their beautiful singing. Sailors who are attracted to the singing fall asleep; the sirens then attack the men and tear their flesh. They sing when it is stormy but weep when the weather is fair.
Unicorn Horse with a single spiral horn in the middle of it’s head. To tame the beast so it can be captured, a virgin girl is placed in its path. The unicorn, seeing the maiden, comes to her and puts its head in her lap and falls asleep. Some accounts say the girl must bare her breast and allow the unicorn to suckle. The unicorn is the enemy of the elephant, which it attacks with its horn, piercing the elephant’s belly. A unicorn’s horn is highly valued. It can be used to detect poison, and if dipped in a poisoned drink, the horn causes the poison to be rendered harmless. Powdered unicorn horn is used as an aphrodisiac. “Unicorn horns” were known to medieval people, but the long spiral ivory horns they saw were actually the long tooth of the male narwhal, a small whale found mostly in the arctic. These could have been caught (or found dead) by Norse hunters in the Baltic Sea or the ocean around Norway, and the “horn” traded in Europe as unicorn horn, either whole or in pieces. Narwhal tusks look exactly like the traditional description of the unicorn’s horn.
Yale The yale is the size of a horse, but has the tail of an elephant and the jaws of a boar, and is black. The yale has very long and flexible horns, which it move independently in any direction. When it fights, it keeps one horn pointed backward, so that if the horn it is fighting with is damaged it can bring the other to the front. The basilisk is the enemy of the yale, and if it finds the yale asleep it stings it between the eyes, causing its eyes to swell until they burst.