DRIDER: Monster Conversion - AD&D 1e to Call of Cthulhu 5e.

Closer to what I'm thinking of than a search for Drider brings up.
Thanks to Arachne, Dante, Dore and Wikicommons for this.

Unless you've already ported Lolth into your Call of Cthulhu campaign (in which case I'm interested in what it looks like now), Driders are 'just' spidertaurs - and the spider part isn't even a spider, really.

Driders aren't a species to themselves, and will be known by chosen/given names or possibly by a local/legendary name for spidertaurs (eg. Jorogumo).

In this conception, Driders have nothing to do with Lolth or the Drow; are no more common in Japan than anywhere else, and have no association with Atlach Nacha or Leng unless they themselves seek it - they can expect no particular favour for similarity of form.

No silk (this is 1st edition AD&D), no Drow spells. Unless you want to.

Drider,  Venom Bloated Composite Multipede.

You become a Drider because you find a way to bind yourself to a giant spider-like body in order to extend your lifespan to study the foul & forbidden, because the Mi-Go do elective/involuntary surgery on you, or because you are struck by a curse. 

You will live well beyond a human lifespan without loss of vigour, as long as you do not succumb to violence or the venom your monstrous body produces. This is ideal for continuing your awful studies, to carry out the will of the Mi-Go, or to prolong your suffering.

Blood is now the perfect food for you, although you can subsist on anything high in protein and/or iron, as long as it’s at least semi-liquid. If you like, you can continue to eat human food for appearance and pleasure, but it is not compatible with your radically altered internal organs and body chemistry - it won't sustain you long term, but it won't do you any harm.

You have fangs, retractable or otherwise, in your human mouth to deliver venom and drain blood. It seems reasonable that you may be able to open your jaw much wider than you used to.

While other configurations are possible, the Drider you are expecting is a spidertaur. The spider section only superficially resembles an arachnid, and could easily have four or a dozen legs as eight. They can be hairy, scaly, chitinous, slimy - anything you like.

The human portion looks as it did in its previous life, although swollen, puffy, discoloured with venom, eventually leaving a permanent mark despite frequent purges (see below). Venom accumulates in the humanoid part at 2 POT/ day, and is uncomfortable to excruciating, with accompanying emotional and mental distress. 

At 12 POT + the Drider will be violently irritable, even destroying allies and important research. 

At 16 POT + it takes a poison attack per day for d6 temporary STR, CON, INT & DEX damage. Once venom is below 16, characteristics recover 1 point per day.

At any time it can purge by biting, ‘milking’ its fangs, or directly tapping its sacs with a blade or syringe - some will have spigots permanently inserted to make this easier. There is bound to be a nefarious text somewhere claiming the venom is the source of the Drider's longevity.

A Drider is composed of conventional matter, albeit unconventionally and incompatibly. They are natives of mundane space/time.

Humanoid Part (when operating on a human scale, eg. embroidery, throwing rocks, picking pockets)

STR 3d6 (10.5)     SIZ 3d6 (10.5)     DEX 3d6 (10.5)     Damage bonus nil

Arachnoid Part 

STR 3d6+6 (16.5)     CON 4d6+6 (20)     SIZ 4d6+12 (26)     INT 2d6+6 (13)     POW 2d6+6 (13)

DEX 3d6+6 (16.5)

Hit Points av. 28       Damage Bonus +2d6     Move 8 

Weapons:

• Human weapons, base % + Humanoid DEX, no db. No particular reason a Drider wouldn't use a bow-and-arrow, and no reason it wouldn't use a revolver either. 
• Grapple, base % + Humanoid STR & DEX. Against human scale targets only; if successful, will Bite on the next round. 
• Bite, automatic if Grappled. 1d4 hits + venom (the Drider can use some or all of its accumulated venom) and/or blood drain (d4 STR per round until dead or set free).
• Crush, 50%, damage = db. A Drider is big enough to crush multiple adult human-sized targets, one for every 12 whole SIZ points its spider body has. If able to jump or drop onto targets, it's 1 for every 

Armour: 2 points on the humanoid part; 4 on the arachnoid. It can choose to wear armour, if available.

At 0 hp or lower, the Drider is dead (unless blown to pieces, disintegrated etc.), but will continue to fight on for three more rounds before finally coming to a stop, even if it’s on fire. It can only make crush attacks & is working on instinct only. The humanoid part flops and flails. 

The same applies if the humanoid part is decapitated, but not if major organs are destroyed. This is not common knowledge - the Drider may not know.

Skills: Dodge (DEXx2 + INT); Climb 90% (but can climb any surface & hang from ceilings); Jump (STR+DEX); Hide 60%; Sneak 75%; Sense Vibrations 40%; Cast Horrendous Shadow 75%.

Spells: Any average Drider will know 0-7 (d8-1). These are unlikely to be directly Mythos related, unless the Drider's state is due to Mythos intervention. 

If a Drider has POW 12+, it knows one spell per point over. 

Habitat: not too far from a plentiful supply of blood, with space for books and experimental equipment.

Sanity loss: 0/1 to see a Drider’s horrendous shadow; 1/1d6+1 to see a Drider; 1/d10 to realise that you have become one.

MUCALYTIC: Monster Conversion - Fighting Fantasy to D&D adjacent and Call of Cthulhu 5e.

It is a MUCALYTIC and you must fight it!
(John Blanche)

From Out of the Pit (p. 84): SKILL 8, STAMINA 9, 2 Attacks, Average Intelligence; stinks so bad you lose 2 STAMINA, and if it hits you three times in a row you get a lungful of its fatal breath.

In the Sorcery! series, you can encounter them in Khare and in Mampang, where they will try to pull the same trick on you - pretending not to be able to hear well or talk above a mutter, then give you a lungful when you lean in.

They left an impression on me.

Mucalytic for D&D adjacent.

Armour Class +2     Hit Dice 4/5    Move 75% Normal Human     Save Fighter 4/5     Morale 8

• The stench of a Mucalytic is as foul as and has the same effect as that of a Troglodyte or a stinking cloud (your choice).
• The breath of a Mucalytic is deadly poison (save or die, or save or 2d6/2d8 hits: your choice), but it has no ranged attack.
• It attacks with 2 blows for d4 or d6 each; it can fight two opponents at once if it wants.
• If both blows hit a single victim, they are grabbed and pulled close - the Mucalytic breathes on them at the start of the next round.
• Anyone slain in a Mucalytic lair will be broken down into a repulsive slime within 3d6 turns if not retrieved. Only their bones remain.
• Mucalytics have Average Intelligence, and can speak & understand other languages.
• It seems reasonable for Mucalytics to share spaces with oozes, slimes and jellies, and to be found in BECMI Black Hag entourages.

Mucalytic, Trunk-Snouted Ascetics of Decay.

In some dismal and filthy wallow, the Mucalytic sits in darkness, murmuring and muttering who knows what to itself. Its indistinct croaking whispers tantalise with the enlightenment found in degradation and decay: "Come a little closer, step into the sacred mire, and receive the Blessing and the Secret."

Mucalytics are composed of conventional matter, being creatures of the mundane space/time continuum. They can see in the dark, and don't like the sun or running water - nothing supernatural, they just dry out/ wash away their beloved slime.

Of course a Mucalytic will pretend to be Chaugnar Faugn or one of its avatars/representatives if that conclusion is drawn; wouldn't you?

STR 2d6+6 (13)     CON 4d6 (14)     SIZ 3d6+10 (20.5)     INT 3d6 (10.5)     POW 3d6 (10.5)

DEX 2d6+6 (13)

Hit Points 17-18    Damage Bonus +1d6     Move 6

Weapons: 

• Sloppy Bash 45%, d4 + db
• The Mucalytic can strike twice in a round, against either one or two opponents. If both attacks hit a single target, it will Grapple them (STR/SIZ vs. STR/SIZ).
• The Blessing 100% if Grappled; poison breath equal to curare (POT 25, immediate onset, muscular paralysis & respiratory failure). The Mucalytic takes no other action.
• Those killed or incapacitated in the Mucalytic's lair will receive the Secret, becoming one with the slime and ooze within 3d6x10 minutes. Only their bones remain, beautifully stripped and clean.
• The stink of a Mucalytic and its surroundings is so rank, all appropriate roles are penalised by 10% unless proper precautions are taken.

Armour: 2 points of muck-plastered hide. 

Skills: Hide 75%; Fool You Twice 35%; Cthulhu Mythos min. INTx2; unaffected by penalties due to slippery, greasy or waterlogged conditions.

Spells: A Mucalytic can expend magic points one-for-one in an attempt to overcome those of a target; success means the victim will approach and bow their head in readiness for the Blessing.

Otherwise, if INT and POW are both 13 or greater, the Mucalytic knows d6 spells - usually Contact spells, and those dealing with extrasensory communication.

Habitat: sewers, storm drains, toxic waste dumps, slimy caves, silted ruins, blighted water meadows - you get the idea. 

Sanity Loss: 0/1d6 to see a Mucalytic; 1/1d6+1 to survive the Secret; 0/1d4 to smell a Mucalytic having encountered one before and failing to overcome it (esp. if you saw someone receive the Blessing).

Commentary.

In converting to D&D adjacent, I'm fortunate that the OotP entry describes them as being 'about the size of a bear'. A SKILL of 8 converts to a 4-5 HD monster according to a conversion document I've seen, so the BECMI Black and Grizzly Bear fit the bill quite nicely.

2d6 Morale & Misery: A Work-in-Progress Subsystem.

Because I think adventures are miserable and scary, and that PCs don't come heroic to the table, amongst the things I wanted is/was some kind of subsystem for that.

Ideally, to satisfy my personal homebrew design conceits, it draws on a limited pool of old school source material, so it's not going to be elegant game design. That said, I also point to the excellent games Best Left Buried and Mothership, which already have dedicated mechanics for this, as well as owing a debt to this post (a good source for Relief and Suffering alternatives, too) by Spwack, which really helped bring it together for me.

This is not meant to be a mental health simulator, and Misery as a mechanic doesn't actually mean you're/your character is sad. 

I'm writing with dungeoneering horror fantasy in mind, but it could easily be tweaked to work for other play styles and settings. It should also bolt onto lots of other systems, as it doesn't have an absolute link to (say) levels or ability score bonuses.

Morale & Misery.

The implied Morale score of a BECMI or B/X PC is 12, because they are exempt from Morale checks. 

Eating away at your Morale of 12 is your Misery, which is the accumulation of fear, horror, grief, emotional damage, dread, shock, and suffering over your adventures. 

Adventurers can start with 0 Misery, if they're well-adjusted, keen to right wrongs, and eager to upend plots against the common weal. Or if they have no idea of what's waiting for them out there.

Otherwise, they start with 2 Misery - this can be the fruit of your tragic backstory, or from your Dark Secret, or because you must be in some dire straits if your best/only option is to go down into the dark, looking for treasure.

Tiers of Misery.

• 0-1: no problem; go about your business as normal - seeking Relief might actually be counterproductive.
• 2-5: it is up to you whether you seek Relief or take on Suffering. At this tier, Misery might drop back to 2/0 when you're between adventures.
• 6-10: on any failed Misery Check, you must immediately (or as soon as practical) seek Relief or take on Suffering.
• 11-12: you can/will do nothing except seek Relief or take on Suffering until your Misery is taken down to 5 or lower. If you fail a Misery Check at this tier, you are Enfeebled and Spent till you can be taken somewhere safe to start your recovery (magic or fantasy healing might help in situ, if that's a thing in your setting).

The Misery Check.

• You can call it a Morale Check if you like, and I sometimes do, because it's different for PCs than for monsters.
• Roll 2d6; you want to roll over your current Misery to pass (so you can't on 12 Misery).
• Rolling a 2 is always a fail, even if Misery is 0 or 1.
• You make a Misery/Morale Check whenever circumstances would call for (for example) a SAN check or save vs. fear. You can also use for tests of courage and resisting temptation. 
• If you fail, you suffer the situational consequences. If you pass, you can carry on.
• Sometimes the consequence is to gain Misery, and a pass might decrease it.

Sources of Misery.

These things can give you +1 to +3 Misery, and you normally get to make a Misery Check as a save.

The following are meant as suggestions; nothing is adamantite, and how you rate and apply them will be dependent on the tone of the game, the setting, and the characters. You can get used to some of the Sources, so that they have no effect in future - this is not always a good thing.

• night out in the cold & wet
• being in a dungeon/wilderness
• just being a 1st level adventurer
• having a Dark Secret
• lithotomy
• surprised by a corpse, a mangled corpse, a monster
• your life is threatened by another
• the first time you have to kill
• reduced to 0 hp (or equivalent state in your game/system)
• the same circumstances as would trigger a Morale Check in monsters
• hungry & thirsty
• trapped/imprisoned
• no chance of surrender/mercy
• robbed
• pinned down and unable to escape/retaliate
• Tired, Exhausted or Spent
• Encumbered or Overburdened
• a really big monster, even just evidence of its presence
• the undead, generally
• supplies run out/spoiled/taken
• difficult moral/emotional choice
• sanity-blasting cosmic horror
• cursed
• lost
• excommunicated
• price on your head
• plague, volcano, earthquake, tsunami, cave-in etc.
• bad omens
• buried alive/wake up in a morgue
• signs of the apocalypse
• alone
• horrifying revelations
• studying forbidden lore
• failure
• betrayal (both directions)
• living under tyranny
• bereavement
• left for dead
• poverty
• addiction/withdrawal
• guilt/shame
• disappointment

Relief & Suffering.

These are the two ways of buying down Misery. Either can be taken immediately to reverse a failed check, but some are more appropriate for downtime activities.

Relief buys down 1, 2 or (exceptionally) 3 Misery. As with Sources, you can get used to a form of Relief and it stops working for you (some have this attribute incorporated).

• Drink and/or drugs. Take 3 times in a row or 5 in total to become Addicted (as the Suffering, but you don't reduce Misery for it). Costs money, could get you into other trouble.
• Retreat. The more you buy down, the more reckless the retreat and vulnerable you are. The only attacks your allowed to make are against those in the way of your escape, friends and innocents included.
• Hot meal, clean clothes and a good night's sleep in the warm and the dry.
• Pampering. A bit of personal self-care, or a full spa day/weekend. Takes time and costs money.
• Asceticism. Gets more effective the longer & more often you do it, until it peaks and effectiveness diminishes but time needed continue to increase.
• Placebo. The first one works, whatever it is, but each one afterwards needs you to pass a Misery Check for it to work. Fail 3 times in a row or 5 in total to realise it was always useless (+2 Misery).
• Faith. A source of comfort, but also mechanically/narratively similar to Drink/drugs, Asceticism and Placebo.
• Rational Explanation/False Scare. If you are convinced that it wasn't what you thought it was, you can buy down the specific Misery you took.
• Charity. Can also be part of Faith; buying down your Misery by actually buying it down. Includes other good works and acts of kindness.
• Swoon. Covers staggered/shaken, involuntary jump back, dropping your weapons, dizzy spell, actual fainting.
• Lash out. Against the Source of Misery, against the nearest thing, living or not. Probably includes going berserk.
• Bloodletting. In a quasi-medieval grimdark fantasy setting, you can get this done professionally (possibly as a Placebo). Being cut in combat might work for you. Equally, it might be someone else's blood that you need to see flow.
• Defend. Shorter term version of Pacified/Demoralised (see below). Boss fights might be exempt, but might not.
• Not being in a dungeon/wilderness. Just go home for a bit.
• As an option, some characters might be able to relieve some Misery - I'm thinking bards, priests (not necessarily the mace-and-plate cleric), druids (in vanilla form) and (why not?) Heroes and Superheroes and paladins; possibly based on Charisma, Wisdom or relative experience.

Suffering is a longer term consequence, but buys down 3 or 6 Misery. You can get Sufferings removed, but that takes time - during which they have a significant mechanic/narrative effect.

• Change Path. You abandon your current class/profession/passion and take up another to pursue; your previous abilities and experience are blocked.
• Doom Seeker. Dig out the AD&D Cavalier class (or better yet, Mockman's comic version) - their combat honour code, you act like that now. Some people think you're really amazing because of it; everyone else thinks you're a monster.
• Addiction. No matter what else you do, feeding your addiction is your primary goal.
• Nervous Collapse. If you do not take to your bed or a sanatorium for a long rest cure, you are Enfeebled.
• Insomnia/Nightmares. Whichever you think is most appropriate - the effect is largely the same - Misery Checks every night or progressively Tired/Exhausted/Spent.
• Crushing Self-doubt. Your confidence in your own abilities is broken, reroll every success unrelated to your recovery.
• Swords into Ploughshares. You turn your back on the adventuring/investigating life. Maybe take up beekeeping, or retreat to the cloister. You can combine this with Asceticism, Faith and Pacified, if you like.
• Ruled by Omens. You spend all the time and money you can on charms and oracles. When the signs are not auspicious, you Suffer Crushing Self-doubt.
• Debauched. You might think you're okay and you're just enjoying a surfeit of Relief. 
• Bad Luck. All your rolls are at -1; this eliminates any bonuses from Ability Scores or abilities, but does not affect existing penalties - they do not get worse.
• Lost in a Fog. Reroll all successes related to Intelligence and Wisdom.
• Wretched. Reduce Charisma by twice as many Misery you buy down (ban or modify this one if Charisma doesn't affect much or is a dump stat in your game). While Wretched, any Relief buys down Charisma 1-for-1. 
• Pacified/Demoralised. The former appears to be a deliberate ethical/moral choice, but the effect is much the same - you will not make attack actions, only defensive. This might save your life.
• Relapse. Take a Suffering you've previously had and recovered from. It probably buys down less than it did, or it's more severe than last time.
• Sycophancy. You try to curry favour from the most important/powerful, available/immediate figure, whether friend or foe. You are effectively charmed whenever the situation presents itself.
• You Monster! You are now able to buy down Misery by inflicting the equivalent on others, you horrible bastard.

Other Methods.

These are not so much things you can do as things that can happen to bring down your Misery.

• Successfully completing an adventure (as defined by the game).
• Gaining a level (or equivalent in unlevelled systems).
• The feeling of security possessing a magical item brings.
• The feeling of security being an expert in your field brings.
• Having a certain amount of wealth.
• Not dying.
• Vicarious victory.
• Becoming a Hero (4th) or Superhero (8th) should probably reset your Misery to 0 or 2 (though it might not get rid of Sufferings), as well as rendering some Sources superfluous.
• Divine intervention.
• Discovery and exploration.
• Falling in love (you can't just declare it; otherwise it's just a specific Sycophancy, and is creepy).
• Recovery from injury and disease (including by beloved others).
• Going to see the Great Clown perform (doesn't work for the Great Clown).

Commentary.

This probably works as presented, but I don't think it's necessarily finished. And it certainly hasn't been play tested, so I'm not even sure that 12 points is enough for an extended game.

As well as the implied D&D PC Morale of 12, I looked to Fighting Fantasy, a 2d6 system.

In House of Hell, your FEAR is the maximum you can bear before you die of heart failure. However, it's tied up in the puzzle of the book and the ratings are all over the place (being threatened with a knife is as scary as witnessing a climactic demonic transformation, for example). You need an absolute minimum of 8 to survive to the end (so can be doomed from the start), and the only chances to recover from FEAR are right at the beginning (when you might have 0 FEAR anyway), and when you have a false scare (which only cancels out the point you just gained).

Beneath Nightmare Castle uses WILLPOWER as a SAN stand-in, and degrades by a point every time you have to Test it - you lose your mind and the game if you hit 6. It is stated that 'you are already tired' (you've been ambushed and imprisoned), which is why you lose your mind at 6 or lower, implying - I think - this would not be the case if you were in a better starting state.

Keep of the Lich-Lord uses RESOLVE, with a loss if you fail a Test, a gain if you succeed. I've not played this book, so I don't know how it feels as a mechanic.

Vault of the Vampire (and its sequel) has FAITH, but this works more like the ability of a paladin-like character than a universal mechanic.

 

Nagpa/Skeksis for Call of Cthulhu 5e

Nagpa from the Creature Catalog (DMR2). Definitely not a Skeksis.

The Call of Cthulhu setting is already infested with ancient humanoids, so here's another one to help fill in some of those millions of years of secret history.

You can go full Dark Crystal with them if you like, but I'm pitching them as another form of 'immortal inhuman sorcerer' and basing them on the D&D Nagpa (which appeared the year after the film was released).

Nagpa, Withered Scholar of the Wastes.

With a vulture-like head and features of both avians, reptiles and mammals, the Nagpa are remnants of an elder humanoid species (though when they flourished in history/prehistory or if they are even native to this dimension/world is unknown).

Hunched over, sometimes crawling on all fours, a Nagpa appears shorter than it actually is, and multiple layers of clothing and ornamentation disguise its emaciated, spindly-limbed (though tough and sinewy) body. Clothing and equipment are usually of conventional materials, albeit remarkably preserved considering the decrepit state and obvious age.

Cursed with immortality, a Nagpa crumbles to dust when slain by violence and then spontaneously reincarnates -fully formed- from a leathery egg sac in some lonely secret place half a world away.. From there, it must begin its miserable existence again, seeking out sources of ancient science and sorcery in an attempt to solve the endless, aching cycle of being.

Nagpa are usually solitary, as they cannot bear the presence of their own kind for long, but do maintain relations with each other, via magical or technological means. They cooperate for preservation, trade in servitors and artefacts, and the advancement of their researches, but each would betray another in a dusty heartbeat for the chance of true death.

While a Nagpa cannot actually 'die' of fatigue or starvation, they feel the effects and can suffer permanent damage within their current incarnation, so they eat, drink and rest as required by their own metabolism and any modifications they have applied.

The Nagpa have a materialistic theological objection to the deities of the Mythos and don't believe in them.

STR 2d6+6 (13)     CON 2d6+12 (19)     SIZ 3d6 (10.5)     INT 3d6+6 (16.5)     POW d6+12 (15.5)

DEX 3d6 (10.5)                                        

Hit Points 14-15    Damage Bonus nil     Move 8

Weapons:

• Skinny claw 30%, d3
• Staff 50%, d6 (Parry 50%, 20 hp)
• Sword 35%, d8 (Parry 70%, 10 hp)
• A Nagpa may also have access to other armaments, including energy weapons, and could have converted those of other monsters to its own use. They will understand contemporary firearms and explosives readily enough, but are unlikely to have previously encountered such human instruments.

Armour: none naturally, but layers of clothing equivalent to d4 points and may wear additional protection.

Skills: 

• At least INT x 2 + any base chance in all appropriate Knowledge skills. Nagpa will specialise in several areas - they have the time and the need to do so.
• Can read, speak, write or otherwise understand multiple languages, potentially including Aklo, Atlantean, Benthic, Cimmerian, Enochian, Lemurian, Muvian, Pnakotic and/or Valusian, as well as ancient/lost human languages, and those of Mythos beings. However, they may be ignorant of modern human languages.
• Hide 50%, Sneak 75%, Mmm. Mmmmm? Mmmmm! Mmmm. 80%

Spells: at the cost of 1 magic point, Nagpa can cast the following spells (these cannot be learned by/taught to non-Nagpa, although a Yithian possession would be able to use them until it left the host):

• create flames sets a non-living, flammable object alight, which will burn as normal until extinguished; it must be visible to the Nagpa. For 3 magic points and an uninterrupted 10 minutes of concentration and visualisation, the Nagpa can cause to ignite an object not present that is has seen within the last 24 hours.
• corruption causes a visible non-living object to rot/rust/disintegrate within the space of a combat round. For 3 magic points, it can do as with create flames. 
• darkness plunges a 'room' into normal darkness; extant light sources are not extinguished. The room must be visible to the Nagpa, but does not need to be completely enclosed (it could also be a tent or a clearing, at the Keeper's discretion). Nagpa can see in the dark.
• paralysis costs 1 magic point per person affected, and the Nagpa must overcome POW vs. POW to do so (it can expend further magic points to boost its effective POW). Victims are unable to move for 1-4 combat rounds, but are aware of what's going in. Nagpa usually use this spell to make their escape or to cast more spells.
• illusion can be static or animated, but makes no noise, is the same temperature as the air, and has no scent; it is dispelled by the touch of naked flesh. The illusion cannot cause actual harm, but how you react to it -thinking it to be real- might.
• (optional) telepathy within-sight universal translator mental communication in case you don't want the language barrier to be a problem/puzzle, or give this power to devices (ill-fitting circlets, for example) found during the scenario.

In addition, a Nagpa will know or have easy access to spells at least numbering the average of their INT and POW. One of these is likely to be Resurrection, for its reverse may hold the key to final dissolution if modified properly. Brew Space Mead and Summon/Bind Byakhee are also common, as most Nagpa will have at least once hurled itself into a star or black hole.

Habitat: anywhere there are the scientific and sorcerous resources for their researches, preferably far from humans: lost cities, abandoned Mi-Go outposts, remnants of Atlantis etc.

Sanity Loss: 0/1d6 SAN to encounter a Nagpa.

Commentary.

I like fiddling with the Mythos canon because it's become so concentrated and static (and this is a criticism that has been levelled all the way back to Derleth), so this is not for purists. 

The Nagpa/Skeksis conversion came about as a side-effect of working on a Random Monster table for Interstellar Space (as the next step on from The Low Moon Itself) - I had a train of thought about non-canonical Byakhee looking like a Skeksis space bee. The Nagpa conversion is the first stop on the way there (and returned the favour with the Space Mead-chugging, Byakhee-wrangling, nuclear-heart-of-the-Sun-plunging idea).

d66/d18 Monsters of the Low Moon Itself.

On the far edge of the Taiga/Tundra, where it meets the Deep Ice, the Moon hangs so low it’s like you could pluck it from the night sky.

 

Under the right circumstances, if you try this, you will find yourself instantly transported there. This is not the only way.

 

Not utterly unlike our own moon - craters, mountains, dust, rocks, a dark side – but it’s a dungeon-studded, factional, fantasy wilderness.

 

D&D adjacent if not system agnostic, and not balanced for probabilities.

 

d66
11,12	Lunar Puddings. Probably clustered in a crater waiting for the sun to charge them up. Less aggressive and less corrosive (½ damage) than Black Puddings – they won’t automatically try to eat you. They go to the dark side to hunt, radiating their solar charge as a slow effect. Cannot consume lunar metals (mercury, silver, magnesium), stone, crystal or glass.
13,14	Gargantuan Shriekers. Sequoia-trunked mushrooms clustered mainly on the moon’s dark side – your efforts are too small and feeble to activate them, but their collective shrieks could level cities – who knows what predators that would attract?
15,16	d666 Ghouls. Not just Ghouls, but d666 Ghouls, so a minimum of 111. There’s not much flesh to be found on the moon, so they’re going to be ravenous, mad with hunger. Only a few of these undead will have intact/ functioning hearing organs.
21,22	d66 Wights. Fortunately for them, an energy level doesn’t need to be drawn from a fleshy or even living thing. But it has made them strange, and they do still desire mortal life energy.
23,24	Pearl Jelly. Lachrymiform translucent ooze-monster. Slowly drags itself around or squats in one place, wobbling. If you lock eyes with something through it, you transfix and hypnotise each other. As well as leaving you both largely helpless and abnormally suggestible during this time, at some point the jelly will identify you as prey and hurl itself at you in a writhing coil of voracious pseudopods. Unintelligent, but migrate across space on moonbeams.
25,26	Cube Warriors. From 5 to 10’ in each dimension, these metallic cubes are remnants of some long-lost civilisation. When activated they sprout a leg and an arm from each face and take up whatever arms are available. No one has ever tried talking to one, or noticed the subtle features etched into their surfaces.
31,32	Lost Goblins. There shouldn’t be any Goblins on the moon, but they sometimes end up here having got lost while travelling by moonlight. They don’t like being on the moon (because Goblin magic doesn’t work here) and they can’t get back the way they came.
33,34	Gargantuan Undead Shrieker (1). Effectively a Wight, with an energy drain touch. Utterly silent. With the right precautions they are a source of exotic resources and won’t object to being hollowed out/ strip mined.
35,36	Mi-Go. Maintain a base/staging post/space port on the dark side of the moon. If you’ve made it as far as the moon, they’ll consider you worth talking to (but not as anything like equals). Field generators on the Astral Plane hide it from Ultraterrestrial Mi-Go.
41,42	Insect Mummies. A lot more Mummies than you’d normally encounter and not of a humanoid species. Prefer their airless, dusty cave-cities and the ageless, fathomless darkness than being disturbed by the living (or other undead). Like the sensation of being full of warm blood.
43,44	Green Spore (1). Splice an underwhelming, low intelligence Beholder or Beholderkin with a Gas Spore and an Ascomid. Spore blasts and Violet Fungus tentacles instead of eye rays. Quivering lens of watery jelly instead of a central eye. No bite or mouth, but it looks like it’s very glum.
45,46	Mercury Nymphs. Mercury in the shape of fem. presenting humanoids, elementals that adapt their appearance to the expectations of the observer. Mesmerising colours play across their shining skin. Their touch is poisonous to mortals, but they do not understand this. Rapidly learn any language spoken to them, but will forget it once they cannot practice. Mildly telepathic.
51,52	Dust Gnomes. Pangolin-like humanoids no higher than your knee. Live in clifftop burrows where the Wights can’t get at them. Herd and ride Strider Fungus. Rolled into a ball, they are impervious to most normal attacks, crushing and falls (poison gas works). Very high mineral content (iron, magnesium, starmetal) and mercury for blood means Ghouls won’t eat them. Unfriendly, but will negotiate for trade.
53,54	Starmetal Pleiad (1). Meteor Nymph from deep space, formed of starmetal (whatever you want that to be), and able to extrude protective plates and offensive flanges to become a war-machine. Tough and fair enough to not need to be hostile, but is a galactic peacekeeper you don’t want to get on the wrong side of.
55,56	The Wight Queen (1). She is very beautiful for an ancient hungry undead thing. If Wights as-a-rule are unintelligent and speechless, she is the exception. Has a radiance that extends her energy drain. Commands the Wights of the moon, but this might be due to a magic item. Has no court or castle, save where she settles at the time. Even though she wanders alone, there will be Ghouls and Wights to call on if need be.
61,62	Strider Fungus. Woody mushrooms with three to seven stems each, standing up to 15’ tall. If disturbed, they will stampede like herd animals.
63,64	Magnesium Nymphs. Look like they’re tightly wrapped in metallic bandages. Languages and telepathy like Mercury Nymphs. Only mildly curious about any business but their own, and not hostile. Unharmed by, but if exposed to fire, they instantly blaze with an intense white flame: will blind/ dazzle you for 4d6 hours if you don’t look away or protect your eyes. While blazing, they are berserkers. Show remorse afterwards.
65,66	Ultraterrestrial Mi-Go (1-3). Accompanied by hideous electronic shrieking buzzing darkness that causes the living to spontaneously haemorrhage - they bring their own dimension with them as they cannot survive long in mundane space. Looking at or near them makes you ill. Treat mundane space Mi-Go as Mi-Go treat mortals.

 

d66/d36 Monsters of the Taiga and Tundra.

From the Glowering Mossy Moors, we find ourselves tramping through snowy forests of conifers that run right against the treeless expanse that encircles the mysterious and unexplored Deep Ice. Nights and days can be measured in short hours or long weeks, and boiling water can freeze in an instant when taken from the flame. Summers, while short, are wet and fecund.

 

The Taiga and the Tundra are not unsettled, nor utterly hostile, but this is about the monster part of worldbuilding.

 

As usual, these are system agnostic but D&D adjacent, and the spread of probabilities has not been balanced.

 

d66	Result
1,1	The Mother of All Bears (1). Bigger than any bear you’ve seen; wears jewellery; prehensile tail; telepathic; spells & magic items. Judge, benefactor and avenging fury of this place.
1,2	Waterwolf (1). Giant carnivorous otter/seal. Haunts the marshes and rivers, but also at home in the forests and on the deep ice. Feared and venerated.
1,3	Furry Hunters. Shaggy carnivorous humanoids armed with long-barreled muskets; very protective of their young. Nomadic, follow the migrating herds. Believed to come from the deep ice, where they use kite- and sail-powered sleds.
1,4	Ogres. Dual-wield cleavers and/or butchering knives; campfire gatecrashers; can be bought off with wine, but will track you down later. Under-dressed for the weather. Surprisingly graceful dancers.
1,5	Goblins. Blue with cold, long red noses; skirts of hide, fur, skin, decorated with jangling scraps; jagged stone knives & flaming torches that won’t blow out; play a selection of instruments made of bones, toenails, tendons and skin. Complain about the cold but will melt away if they spend too long by the fire.
1,6	Elves. Naked, so white, with all-black eyes & jagged bright red hands and mouths; you can never see their feet; live in Frost Drake tunnels; raise human children as shaman/sorcerers; vulnerable to iron, but not to holy. Can remain unseen to mere mortals.
2,1	Frost Drake (1). Multiple pairs of legs, scales, pelican jaw, shaggy mane head to tail tip, alicorn; superheated insides; curious, not-unfriendly, intelligent animal; excavates/melts extensive tunnel lairs.
2,2	Blood Puddings. Leathery pods containing a meat-like ooze. Use charm to have you keep it close to your body, keep it warm and protect it. Finds it easier to convince you to let it take small amounts of blood, but prefers you to kill so it can feast. Intelligent, but selfish and unimaginative. They are found in groups initially, but one with a host will have it destroy the others.
2,3	Hyperboreans. Bearded redheads from prehistory (reskinned B/X Elf). Stone Age equipment. Invisible environment-controlled dome cities full of wondrous and mysterious technology, hidden in the ice. Vulnerable to vampirism. Friendly with Hairy Brutes.
2,4	Abandoned Creations. Odds/evens, they’re frozen solid (but can be revived/thawed); undead, flesh golems, clockwork, living statues etc. How long have they been here? Why are there so many?
2,5	Wind Walkers. Gruesome aerial ghouls; levitate and then drift/fly on the winds; burrow under the earth/ice/snow during the day, but can go out just fine in a blizzard. You can never see their feet.
2,6	Squid Heads. Low-rent, off-brand mindflayers; hate Furry Hunters; black-powder spear guns; levitate and fly like Wind Walkers; conquer & move into lairs; hunt Frost Drakes. Skinny, warty and mauve.
3,1	Father of Toads (1). It’s just a name; giant, shaggy toad; can survive freezing solid; can squash itself down to hide in shallow water/long grass; grows as big as food allows; long drawn out roar from throat generates confusing vibrations; swallows whole; carries its young in its pelt.
3,2	Winter Dryads. If more than 1, it’s the mustering of a warband. Human civilization might not be their target. Friendly with Hairy Brutes.
3,3	Nomadic Worm (1). Colossal armoured tank of a thing; two huge feathered mandibles; huge gem-like eye spots all along its body blink with coloured lights; blast furnace gut/jaws; emerge as Ravenous Larvae in the taiga, survivors devour all in its path to the ice to pupate.
3,4	Phoenix Moth (1). Adult form of the Nomadic Worm; vast, fiery and beautiful; fertilisation by eating the males; females then fly to the taiga to lay eggs, then die; extinguish, discolour and liquefy in a matter of hours; residue is highly prized.
3,5	Ravenous Larvae. Lucky for you, they’re just as keen on eating each other; unlucky for you, they’re eating everything anyway. As long as they don’t all start coming after you at once, you should be able to get away.
3,6	Dwarves/Trolls. You can’t really tell the difference between them; friendly, welcoming, generous through the long night; at daybreak, they’ve taken down their tents, put out their fires and left you asleep in a snowdrift. Outdoors, under the moon, they become flesh-eating killers. Can see Elves and smell Goblins.
4,1	Hairy Brutes. Don’t speak your language; they’re definitely subhuman cannibals that need to be wiped out. A sophisticated, highly cultured society that hasn’t been given a decent break since your kind started competing for space on the savannah. The Mother of All Bears loves them like her own cubs.
4,2	Mounted Wights. (d6) Palanquin carried by Winter Woses; Sleigh pulled by Skeletal Giant Elk(s); Howdah on a Skeletal Mammoth; Saddled on a Skeletal Sabre-tooth; Cage carried by a Skeletal Giant Bird; Warband on Ghoul Horses.
4,3	Vampires. There’s tension between the locals and the tourists. Tourists have cordial relationships with Squid Heads and share their lairs. Locals don’t like sharing the endless night, nor the disruption to infiltrated prey communities.
4,4	I-nomes. Brutal elementals; hairless naked Dwarves of solid ice; strong as giants; vulnerable to fire, but extinguish it; they can just about tolerate Vampires and Winter Dryads, but all other things must bow and perish before the snow. Have never bested the Mother of All Bears.
4,5	Boreal Bugbears. Much shaggier than their subterrene kin; grey to white fur; know where Black Ichor bubbles to the surface and where lie the old Hyperborean temples to Tsathogghua.
4,6	Mi Go. Mining rare elements either from the earth, or the ice itself; searching for something buried in the ice from ancient days, so know where lots of other things are; disguised as Furry Hunters, Hairy Brutes or Boreal Bugbears, they are almost convincing. Uneasy truce with Hyperboreans.
5,1	Shaggy Beast (1). A hill of a thing; a baggy, boneless mound of elephant hide on stumpy legs that come and go. Draped in writhing hair, with an unanchored mouth flap that can extend and twist into a trunk. People say it’s a rogue bear or possibly an extant mastodon, but they’ve never seen it. Horribly strong, barely sentient.
5,2	Flickering Eidolon (1). Reskinned Boggart (1e AD&D MM2). Believed to be spirits of the dead, but who can say if it’s true.
5,3	Children of the Pines. Sap-infused undead children riding white-and-red Elf Hounds (Elves transformed with a special bridle); reskinned B/X halflings that get AC bonus vs. human-sized. They want to drive adults off, rather than kill them – but will: the taiga is their Neverland.
5,4	Lonely Shoggoths. Vaguely humanoid lumps of leathery flesh. Split-off from their main mass, they want to be reunited; miserable in a way individual intelligences can’t understand; enjoy poetry and music; sometimes tag along with Goblins.
5,5	Winter Woses. Much like Wood Woses, but look more like Hairy Brutes. Hate Vampires, especially tourists.
5,6	Land Kraken (1). A dynamic colony of lichens and fungi with inchoate sentience and dim awareness of the universe; animals that eat it regularly may become intelligent, capable of speech, loyal to the colony; intelligent beings can commune with the universe using colony as a conduit; the colony does rather like to be nourished with blood from time to time; can extrude puffy tentacles if needed. Are there several or does one cover thousands of square miles?
6,1	Tusked Moles. Nocturnal/subterranean burrowing mammals; undermine and eat what falls in; killed instantly by sunlight or enough water; not very bright; enjoy moonbathing; at home in earth or deep snow; horrible screeching.
6,2	Psychic Eels. Hefty freshwater eels; good eating; zap you with random psionic abilities as a defence (or enfeeble, paralyse, charm if you’re not using psionics); unintelligent. Squid Heads can’t use their powers while in or against those in eel waters.
6,3	Fire Cats. Roam the taiga, gather at volcanic springs and lightning strikes; alarming blue faces and orange-tipped pale fur; can cough up a sputtering fireball. Actually a species of ape, but felidiform.
6,4	Greater Wood Troll (1). Becoming more like a vast and ancient tree as it survives the centuries. Rarely talks anymore, because it’s so sad. Can pass without trace, despite its size and spread. It is an old friend of the lightning and the wind, and can call on them for aid.
6,5	Liver Eaters. Stride with great padding footsteps, muffled by the carpet of needles or the snow. Sometimes towering, other times small enough to hide in your backpack. Bright-eyed, waxy-skinned, skeletal. Just want to eat the little bit of your liver that means you’ll waste away and die.
6,6	G-nomes. Brutal elementals; naked, hairless Dwarves of tree trunk and creeper; strong as giants; despise all non-plant life. Plant trees to extend the forests, watered with blood and fed with crushed bone.

 

As well as the Moors, one can find their way back to the Great Grim Gloomy Forest which interfaces with the Taiga at various points.