Nuckelavee: The Devil of the Sea
A fiendish column on using folklore in tabletop RPGs
Summer is long over. The Sea Mither has lost her battle against Winter. The Orcadians sense evil walks amongst them once again. There is no trickery or joy in this creature. There is only malevolence and hate.
The nuckelavee, a spirit in flesh, is free.
Has Mythoi featured an evil greater than the nuckelavee?
Creatures like the beithir and tatzelwurm are ultimately beasts, driven by primal instincts. The headless dullahan acts on behalf of death itself. Even the four horsemen of the apocalypse were created to serve a purpose.
The nuckelavee, instead, is malevolence made manifest.
Deriving its name from the Orcadian knoggelvi, nuckelavee ultimately means "Devil of the Sea". This enormous creature resembles a man riding a horse, except that his torso merges into the horse where the rider would normally be seated. Its head is ten times the size of a human, pig-like with an enormously wide mouth. The horse itself has a singular red eye that burns with a red flame. The nuckelavee is skinless, a creature of raw flesh and pulsing black veins.
The nuckelavee’s breath is a horrid poison, blighting flora and causing disease in animals. The sea-devil is blamed for livestock disappearing, plagues and epidemics, and prolonged droughts. An unusual quirk of the nuckelavee is that it takes great offence to the burning of seaweed; the mere sight of it driving it into an uncontrollable rage. Once, it vented its wrath by inflicting every horse on the island of Stronsay with the deadly disease mortasheen (likely what is now known as glanders).
According to folklorist Walter Dennison:
“This being was looked upon with unutterable horror, was regarded with mortal terror, and spoken of with bated breath. He was a monster of unmixed malignity, never willingly resting from doing evil to mankind. Indeed, if not restrained by the Mither of the Sea in summer, and winter by his terror of fresh water, he would long ago have made Orkney a manless desert.”
Indeed, the only weakness the nuckelavee is said to have had is its intense fear of fresh water. If you encounter it, your only hope is to make it across a loch, river, or stream. If you can’t do that, then all that’s left for you to do is to pray for rain.
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II. Mither of the Sea
No mortal can stand against the nuckelavee, which means the people of Orkney must rely on the benevolent Sea Mither/Mither of the Sea to protect themThe spirit of spring and summer days, she quells the turbulent sea waters around the north isles of Scotland. Nowadays, locals and fishermen invoke her name as protection against the Devil.
In Orcadian folklore, the Sea Mither is locked into a continuous battle against her arch-enemy, the winter spirit Teran. Their back-and-forth struggle creates periods of peaceful summer weather (when the Sea Mither is victorious and imprisons Teran) and periods of terrible winter storms (when Teran breaks free and forces her to retreat to rest). An annual problem then is that the Sea Mither also keeps the nuckelavee trapped in the ocean depths during her summer months, meaning the demon can roam free when Teran is in charge.
So, I guess what I’m saying is that maybe you should line up any future Scottish vacations with warmer weather.
III. Dangerous Company
No discussion of the nuckelavee can be complete without noting that it’s in prestigious company. Water horses, such as Scotland’s famous kelpie, are a recurring creature throughout world mythologies. I wouldn’t recommend taking a ride on any of them though, just in case.
We’ve actually already discussed a topic with such a creature—Queen Malgven and then King Gradlon of Ys ride the water horse Morvarc'h, capable of galloping over the waves.
I have no doubt that the nuckelavee and Morvarch’d won’t be the only times this subject comes up—humanity loves putting a horse in water!
Using the Nuckelavee in Your Game
Now you know the story, how can you use it in your game?
Delving a Water Temple
The nuckelavee hasn’t menaced the coastal villagers of your fantasy kingdom for some time, ever since great heroes in the past helped a sea goddess seal it away for good. But now, enemies of the kingdom have found a more devious way to defeat their foe than simple open warfare—getting the nuckelavee to do their job for them! They’ve travelled into an undersea temple or dungeon* in search of freeing the devil from its prison. Can the party stop them in time?
*Everyone loves a water temple, right? Here’s your chance to include one!
Like so many folkloric creatures, the nuckelavee is a creature that brings with it poison and sickness. In the case of the sea-devil in particular, it once cursed all the horses on an island with the deadly disease mortasheen. If you abstract the effects to be more fantastical, a race against time to lift the curse of mortasheen from their horses and livestock could make a great rural adventure in a fantasy or pre-modern setting (e.g. Vaesen).
Linking with our themes of fresh water, perhaps our party needs to locate and travel to an ancient sacred spring. It’ll be a dangerous trek, one heading deep into a dark forest or treacherous mountain range, but the alternative is tragedy. Only through the healing water of the spring can the livestock of their home be saved.
Nuckelavee Statistics (Old-School)
Armor Class: 3 
Hit Dice: 9** (40 hp)
Attacks: 2 x hoof (1d6), man: 1 x weapon (1d6 or by weapon), horse: 1 x bite (2d6) or 1 x breath (3d6 + disease)
THAC0: 12 [+7]
Move: 120’ (40’) / 180’ (60’) swimming
Save As: Fighter 9
▶ Attack pattern (horse head): 50% chance of breath attack, otherwise bites.
▶ Breath weapon: Can be used up to three times per day. Creates a poisonous cloud 50’ long, 40’ wide, 20’ high. All caught in the area suffer damage (save versus breath for half) and become diseased (save versus poison to avoid, +4 if the save versus breath was successful).
▶ Disease: The victim is sick for ten days (no physical activity possible except half speed movement).
▶ Mundane damage immunity: Can only be harmed by magical attacks.
▶ Poison immunity: Unharmed by any form of poison.
▶ Magic resistance: Unaffected by illusions, sleep, charm, and hold spells. Can detect invisible creatures within 60’.
The poison expelled by the nuckelavee immediately kills all vegetation and creatures with less than 1 HD within range, then dissipates after 1 round.
And that’s it for the nuckelavee!
Thanks for reading; our next column places us squarely inside Yuletide, so we’ll be finishing the year by taking a look at Yule’s least well-behaved cat!
Penny for your thoughts: What’s the nastiest demon or devil you’ve fought in a role-playing game?
~ A.C. Luke
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Dennison, Walter Traill. 1891. “Orkney Folklore. Sea Myths”. The Scottish Antiquary, or, Northern Notes and Queries 5.19: 130-133.
Westwood, Jennifer, and Kingshill, Sophia. 2012. The Lore of Scotland: A Guide to Scottish Legends. Random House: London.
Dennison, Walter Traill. 1891. “Orkney Folklore. Sea Myths”. The Scottish Antiquary, or, Northern Notes and Queries 5.19: 131.
Marwick, Ernest. 2011. The Folklore of Orkney and Shetland. Birlinn: Edinburgh.
I love your work. I was excited to see today’s topic, because I’ve actually heard of this one! It was used as a big bad guy in a book series I read.