That Night, A Forest Grew - d66 Monsters of the Sidhe Dream

A circumstance of para-Moorcockian science-fantasy, rather than a location. 

The subtle dimension allowing the so-called fairy folk to radically change shape and size, demonstrate disproportionate strength and take seven-league steps without suffering the consequences of mundane physics. 

Bypasses rationality, allowing animals to speak, the body to survive dismemberment, and lives to be lived fully between the ticks of a clock. As a hyperspace dimension, it is also a way to other places. 

Most reliably occurs on small islands, along riverbanks, at dawn and dusk, at the crossroads, along the treeline, on the shore, in desert oases, ruins and abandoned facilities, on the old straight track, deep in your cups, on sartain nights of the years, wells and springs, in mines, on train-tracks and at bus-stops, motorway service stations, under-maintained and remote parts of generational colony ships and post-apocalyptic quasi-utopian high-tech mega-bunkers.

Roll d6:

1. Roll d6:

1. Owlboars: Squealing, hooting pack of magical hybrids. A challenging meal, but delicious roasted. Capable of climbing and jumping out of trees. Cough up whole mummified corpses. Filthy and riddled with parasites.
2. Hyacinths: Child-sized with bouncing golden curls, goat eyes, forked tongues. Echo, mimic and ventriloquise to lure you from the path. No language of their own. Possibly telepathic.
3. Ophilines: Languid serpentine cats; wind themselves around branches; cannot constrict but can wrap you up to keep you warm or for auto-bite/claw. Intelligent animals that choose not to talk.
4. Shivery Boys: Blue-skinned and frosty, lost boys left out in the cold. Fairies took them in, then got bored with them. They call themselves Jack or Peter or Robin and are looking for ways back to the mortal world. If not already vampires, they will be once they get back home.
5. Surprise Hunting Boulder (1): Greedy for flesh and blood. Once it has chosen its prey, it can reappear wherever and whenever you aren't looking - including your dreams and understairs cupboard. Moves by rolling and tumbling when under observation, or when it wants to make a lot of ominous approaching noise. Thinks it's a lot more charming than it is.
6. Dire Erudites: Reptilian/dinosaurian druids. More like Hierophant druids than the ones of the mortal sphere.

2. Roll d6:

1. Feliquines: Cat-headed, cat-pawed, cat-tailed, cat-patterned horses; approx. 25% have venomous spines along their flanks. 2 on 2d6 it’s a lone Felicorn (with special abilities and a sought-after alicorn).
2. Corpse Elves: Instinctive glamour to appear as a corpse, often someone you know, making them unnerving interlocutors. Teleport via damaged/dead/dying trees. Meld with living trees to regenerate. Initial Reaction Neutral to Friendly.
3. Mousebear (1): Confused cyclical shape-shifter with a tail attack - damage as dagger for mouse, as polearm for bear, special effects from a monster you’d otherwise not use. Even the bear is afraid of the mouse.
4. Crimson Cattle: Soft red hide thick as plate armour; their meat, milk and blood cure physical, spiritual and societal ills. Glamour makes them seem a blazing, roaring, sun-blotting, town-crushing bovine sky-scape dominating the horizon. Intelligent. Variously capable of speech, spell-casting, prophecy and keeping-their-own-counsel. Have a taste for mortal flesh, but not compulsive gourmands. Horns are magical weapons.
5. Zoogs: Tentacle-faced tree-otters. As likely to track, torture and eat you as to share moonwine and news from beyond the fields you know. Sly, stealthy; pretty much like you’d expect. Implacable foes of the Vroons.
6. Shrill Viridian Things: That haunt bleak rivers. You can hear them from a mile off, but that might be ventriloquism. Maybe cross a Phase Spider with a Quickling for inspiration.

3. Roll d6:

1. Wamps (1-3): Blind, snuffling, mammalian, spider-like profusion of legs. Bat-ears and web-paws bright blood red in contrast to bone white skin and corpse grey fur. Thrive on a diet both ghoulish and vampiric. Mate with and grow/hatch from heads/skulls - detached, dead, whatever.
2. Skandars (Treebeards): Towering, hairy, multiple arms; masters of archery, hammerspace and juggling. Sometimes grow thoughtful and go into an overgrown, Ent-like hibernation.
3. Vroons: Amphibious golden-eyed little octopus folk. Walk upright. Talent for mind- and emotion-affecting magic. Generally benevolent. Sworn enemies of the Zoogs.
4. Sandestins (1-3): Elementals of Primal Chaos, unshackled by Time, hidden from Fate, evading Paradox, circumnavigating Error. Everyone is scared of their open-ended ability to manipulate reality. Comfortingly vulnerable to magical binding and command.
5. Wasp Elves: Aposematic nymphs. You bet they’re going to lay eggs in you. Not hostile, but self-interested and dangerous. Larvae (babies) have ranks of chitinous teeth, which they shed shortly after eating their way out of the host.
6. Piss-a-beds (Gnomes): Natural banded armour and venomous spittle (anaesthetic, anticoagulant, lingeringly diuretic). Pangolin-woodlouse things with a taste for blood. Glamour to look like piglets or great grey grubs.

4. Roll d6:

1. Hairy Nuns: (d6) 1 lascivious lamiae, 2-5 neutral clerics, 6 bloodthirsty Ogres in (magical or unconvincing) disguise. 
2. Tusked Knights: (d6) 1 clumsy buffoons, 2-5 incorrigible but more-or-less honourable duellists and jousters, 6 day-walking Vampire Wereboars. Gorgeously carved wooden plate armour; arrows that sprout into saplings. 1 on d6, they’re mounted on Feliquines.
3. Horned Monks: (d6) 1 satyrs, 2-3 neutral clerics, 4-5 mortal Inquisitors rooting out the devilish and glamour’d to ignore their own horns, 6 bloodthirsty Ogre magi in disguise. 
4. Bastard Uncle Toad (1): Troll/Vodyanoi with aspirations of godhood. Become his cleric (carrying his questionable doctrine abroad) – he grants spells up to 4th level (but you must visit him each time for 3rd-4th level spells), keeps your soul in a crystal pool as security, and calls you back as a zombie if you die in his faith. 
5. Maggot Elves: Magpie-plumaged goblin-harpies that like to eat living brains. Inappropriately friendly and conversational during and immediately after feeding. Can sniff out your dreams and desires, to pick out the most luxurious meals. You can (sort of) survive them eating your brain.
6. Homecomers: Bundles of hair, bone and fingernails, lumps of rocks, rotten stumps, and so on that the fairies leave behind when they steal your babies, but all grown up now and exercising their glamour and right to life. They know they're not people now, but they know who they were before.

5. Roll d6:

1. Janus Elves (1-3): Double-headed psychopomps, precogs and demon-fighters. Numerous Orders and Companies - with elaborate rituals, signature special moves, outlandish weapons, and awesome livery - each made up of no more than three members.
2. Wood Pigs (Gnomes): Armoured moth-bears with powerful climbing, digging, rending claws. Have a taste for gold and other precious metals. Disproportionately tough for their size. Sometimes known as aurumvorax.
3. Grandmother Spider (1): Wizened and kindly (but otherwise trad./RAW) Dark Elf matriarch. Loves all her small and giant charges, in the mundane world or otherwise, and they speak to her, so she knows how many you’ve killed and if you’ve broken any spider laws that you have no chance of knowing in advance. Near to or crouched on top of a cottage-sized obsidian sarcophagus, which can uproot itself like Baba Yaga's chicken-leg hut.
4. Sasquatch (aka Dark Watchers, Owlbears):  Shaggy, Human to Ogre-size darknesses, with three restless white marks (eyespots?) approx. where the heart would be if they are as humanoid as they seem. Presence accompanied by chill, stench, the dampening and disruption of glamour. 
5. Mandragora Mandragon (1): Draconic ceratopsian Dire Erudite and Ogre Mage. The Great Druid to beat to rise to the top of the hierarchy in this continuum (turns Hierophant with good grace if you do). 
6. Sleeping Beauties (1-100): Glamour'd Coffer Corpses.

6. Roll d6:

1. Dark Elves (1-100): Dead white skin, lustrous black hair, blank nacreous eyes. Submerged deep in the Dream, they rarely wake. Bunched close together or standing alone, they sway as if by currents of air and water. Their glamour walks abroad, acting out their dreams and neuroses.
2. Lost Wolves (2-12): Baffled and cautious, the Dream has given them understanding and they would like to get home and go back to being animals, please. 1 on d6 accompanied by a mortal child they are protecting or raising. 1 on d12 this child is a Shivery Boy taking advantage.
3. Light Elves (1-3): Beautiful, noble, radiant. Their backs are always towards you and they are always just out of reach while your eyes are open to see them. Prey on the recently dead, the dying, and dreamers/sleepers. 
4. Mothmen (aka Camazotz): Related/similar to the Sasquatch, but with vast spreading wings and red marks/eyespots. Sandestins fear and hate them. The source of those distant and mysterious whale-songs in the deepest woods.
5. Melancholy Ogres: The Dream changes you, and these anthropophagous brigands feel remorse for their horrible crimes and grisly feedings. Help them back to the mortal world and they will reward you with buried stolen treasures and locations/remains of victims. The Dream fades fast and old urges return.
6. Blood Moon (1): Amorphous, gelatinous, cloud-like; leering aerial-amphibious predator. Frightens your bones to jelly, then sucks them out of your still-screaming body. Can squeeze itself small into a burrow or hollow tree, or spread out over the surface of a pool. Not native; trapped in the Dream, but thriving.

Commentary.

Basic inspiration, Sidhi Dream as featured in Moorcock's Chronicles of Corum colliding with the Lovecraftian Dreamlands.

Pronounce it how you like - it was years before I realised Sidhe didn't rhyme with giddy. But maybe Moorcock's Sidhi does?

Probably also inhabited by variations on the Hjorts, Liimen, Ghayrogs and Metamorphs. Lord Valentine's Castle marked a shift in my mental universe, though it was my springboard into Jack Vance rather than pursuit of Silverberg.

Janus Elves a collision of Majipoorian Su-Suheris and an alien species from The Dead (Pete Milligan and Massimo Belardinelli's 1987 strip for 2000AD).

Elves, Goblins, Trolls, Dwarves, Greys etc are local manifestations of cosmos-/dimension-spanning kindreds you could circuitously eventually identify as Eldar/Eldren - selection/evolution over strange aeons and from settling stranger places.

For existing older-edition supplements that might help with fleshing out encounters and adventures in/adjacent to the Dream: The Nightmare Lands (2e Ravenloft, the eponymous domain), and Blood Spawn (2e Birthright, the Shadow World/ the Seeming). Missed these the first time round. Damn.

Secrets of the Plague Doctors - The Pharmacopeia.

A medicinal miscellany suggested by the Plague Doctor class, or that turned up in the research.

Gary Chalk/ Flight from the Dark/ 1984

No price tags attached, because the Plague Doctors will charge as much as they think you can afford - though not as much as for clerical healing (until they've safely toppled the temples).

Usual * for extra-optional.

Anaesthesia and Pain Relief.

These certainly put you in an Altered State.

Ether/Chloroform: roll 3d6 each round to beat unwilling patient's Constitution (or save vs. poison) to KO them for 1 hour; grapple/Strength to administer via rag or mask.

Patient cannot normally be woken by damage/pain while in effect.

Paralytic: equal to Ghoul's touch. Save vs. coma if two doses overlap.

It's optimistically described as an anaesthetic. At least the surgery can be performed undisturbed. 

*If actually derived from Ghouls, recipients risk exposure to the corpse-eating sickness and/or rising as Ghouls if they die while under the effect.

Sleeping Draught: patient sleeps for 2d4 hours in 3d4 rounds; they are allowed a save each turn if resisting the effect (*slowed and immune to fear during this time).

Double dosing puts the save at disadvantage/penalty and a crit fail leaves the patient in a coma. 

A triple dose is proof against nightmares, dream intrusion and spirit possession. While awake you are temporarily immune to non-lethal damage and are subject to post-hypnotic suggestion.

If you take 3 or more doses in a week, save vs. addiction. If you take 6 or more doses in a week, save vs. addiction at disadvantage/penalty.

If you take triple doses 3 or more times in a week, save vs. coma for each triple dose thereafter.

Double and triple doses are considered effective anaesthesia; a single dose is aftercare. 

Soma: Commandeered from the Druids in the name of science. Makes you feel immortal.

A full dose has the following effects: halves non-lethal/subdual damage taken; -1 hp lethal damage per damage die; +4 save vs. stun, and fight on at 0 hp (to whatever is the negative hp limit used at your table), but make all Dexterity-based rolls at -4.

They will attempt to strip off their armour/clothes and drop their carried equipment if not restrained. 

Lasts d3+1 hours.

If you take it 3 or more times in a week, save vs. each dose or lose 1 Constitution permanently. 

You can take it twice in a day, but must save vs. hallucinations (or second sight). If you take it thrice, save vs. overdose at disadvantage/penalty (effects as for cough medicine, immoderately used, or purgative, plus Constitution loss).

A normal dose (barely a pinprick in a sugar pill) is enough to ease general aches, pains and fevers for d3+1 hours with no other mechanical effect. You couldn't fit enough pills in you to get anything resembling a full dose.

*Possibly derived from a dangerous and/or intelligent mushroom monster (e.g. Violet Fungi, Myconids).

Healing Herbs.

Whatever occurs naturally, that would be processed and prescribed by your setting's herbalists, folk healers and apothecaries, is potentially available to the Plague Doctors.

Some iterations of the Plague Doctor organisation will condemn folk remedies etc. as being superstitious nonsense, and/or perceive them and the practitioners to be a threat.

Healing Salve.

I generally think of healing salve as giving +1 to natural healing, even when active/adventuring (or doubling the effect). Even in a high(er) magic setting, it's a non-magical medical treatment.

You decide whether this stacks with or is already abstracted into the Plague Doctor's Treatment ability.

Or, if you prefer, the more potent version from 2e Sages & Specialists: 1 hp per day active/adventuring, d4 hp per day resting, d4+2 hp per day complete bed rest (*or these could be increments of efficacy, black mummia to alicorn to golden mummia).

Alicorn (Unicorn Horn): whether this actually contains any Unicorn will depend on your setting, but that's what it's branded as.

One dose is equal to a half-strength purify water spell (a 6-inch cube) and, applied to an infected wound, gives a new save vs. infection.

It's also an active ingredient of healing salve (see black mummia), though not necessarily in purity/concentration enough to purify water and fight infection in addition.

Black Mummia: extract of mummy (post-mortem process).

Touted as a general cure-all, but principally an active ingredient in healing salve.

If it has been harvested from an undead Mummy, after 1 week of use you must save vs. addiction. 

Once addicted, you must save after each week of continued use or contract Mummy/Tomb Rot. 

Once this kills you, you rise as one of the undead (d8; 1-5 Zombie, 6-7 Ghoul, 8 Mummy).

Golden Mummia: extract of mellified mummy (pre-, para- and post-mortem process). 

Touted as a sovereign cure-all, but principally an active ingredient in healing salve.

It is no more effective than black mummia, but significantly more expensive and renowned.

If it has been harvested from an undead Mellified Mummy (approximately, Mummy + Adherer), after 3 consecutive uses you must save vs. addiction. 

Once addicted, you must save every 3 uses or contract Honey Rot (as Mummy Rot, but also produce 2 pints of Killer Bee honey per day - anyone consuming this must save vs. disease).

Once this kills you, you rise as one of the undead (d8; 1-5 Ghost, 6-7 Mellified Mummy, 8 Vampire with bee affinity/abilities).

Prophylactics.

An ounce of prevention and all that.

Graverobber's Balm: goes by a number of other names, such as Four Thieves Vinegar.

Gives advantage/bonus to saves vs. disease for d6+6 turns. Additional doses extend duration, but are not cumulative.

It gives an additional small bonus (c. 5% or +1 or equivalent) to saves vs. diseases and parasites carried/spread by the undead. 

*Depending on your setting assumptions, this could be applied to Ghoul paralysis, too.

Mithridate: advantage/bonus on saves vs. disease/poison for 3+d3 hours.

If doses are overlapped, you are nauseated for that time.

If you take theriac while taking mithridate, they neutralise each other.

Remedies.

Tried and tested. No snake oil here. Some of them might put you in an Altered State.

Cordial: new save vs. non-magical conditions (excluding disease and poison); +1 save vs. non-magical cold for d4+4 turns.

Once per night, a dose of cordial allows you to ignore the effects of fatigue for d4 turns. It will also delay the effect of sleeping draught for the same amount of time. Further doses feel restorative but have no mechanical effect. 

More than 3 consecutive doses in 1 hour is emetic. Pace yourself.

Cough Medicine: gratifyingly effective.

Used immoderately, for d8 hours the patient suffers weakness, has second sight and must roll for astral/ethereal/psionic random encounters. Save vs. poison or lose 1 Constitution permanently.

Probably an opiate of some kind.

Elixir: restores patient to 1 hit point if at 0 hp/Casualty State, and/or down to -10 hp if administered within 6 rounds (use your judgment).

Gives advantage/bonus vs. aging damage and on non-magical death saves for 6+d6 turns.

Emboldening Vapours (Smelling Salts): immediate recovery from unconsciousness (including sleep) and nausea, and you get a new save vs. non-magical shock, stun, fear (including any secondary effects such as paralysis or weakness), and confusion.

It will restore 1 hp to someone currently reduced to 0 hp by non-lethal and/or subdual damage.

Patient is staggered (later-edition condition if no rules) for the round in which vapours are administered. 

They may also ignore any effects of fatigue for the next d3 rounds, and each dose delays sleeping draught for 1 turn.

Emetic: if taken within half the onset time of ingested poison (or within 6 rounds if not using onset time), patient gets an extra/new save (or save at advantage/bonus).

You are nauseated for 2d6 rounds (as the later-edition Poisoned condition, if you don't have rules already).

Also works on some internal parasites, and could be ruled helpful vs. certain magical potions (and other consumables).

Nepenthe: medicine for sorrow and post-surgery trauma; patient must fail their save in order to forget (the last 24 hours, or 3d8 hours if you prefer dice rolling).

Combine with hypnotic suggestion to suppress specific memories

After the 3rd effective dose, patient must save vs. addiction (or use some rules for opiates).

Panacea: effective against any non-magical negative condition.

New save if administered while suffering (oral or injection). 

Save at advantage/bonus if administered in the same round as the condition is bestowed/takes effect (injection only - Plague Doctors can do this automatically as long as they are not incapacitated/restrained and are within range; other characters must roll Dexterity or Initiative to do so).

Purgative: save vs. poison; success=weakness d6 hours, failure=sickness (as Centipede, Giant).

Even if you make the save, you're narratively shitting and puking for the duration.

Works on some poisons (see emetic) and some internal parasites, but it's mainly used as part of a general treatment programme (regardless of whether it's useful).

Allows a new save vs. addiction when you first become addicted.

Theriac: gives a new poison /venom save if administered within one-third of onset time (or within 6 rounds if not using onset times).

Multiple consecutive doses can be administered.

Supplements.

Not every discovery has a clear medical use.

Ambrosia (Beauty Cream): the economic cornerstone of the pharmacopeia.

One dose gives +1 to Comeliness, and if you use it consistently for 10 days, then daily thereafter, the bonus is +2.

As nobody uses Comeliness, this is meaningless.

*Source is 2e Sages & Specialists and it's a Charisma bonus (cf. philtre).

Aphrodisiac: it contains enough emboldening vapours (stimulant), nepenthe, sleeping draught and soma to make you think that it's doing something - particularly when taken in the appropriate circumstances (at a party, in the boudoir). 

Social overuse mechanics can be reskinned drunkenness rules.

*Aphrodisiac is also a commercial euphemism for abortifacients, contraceptives and bogus fertility treatments.

Emboldening Vapours (Stimulant): ignore levels of fatigue for d6 hours at a cost of temp. -1 to Wisdom, Dexterity, Charisma per dose.

You can hold off fatigue for max. 36 hours before needing to save vs. d6 temp. Strength and Constitution damage per dose.

After 3 consecutive doses, save vs. addiction per dose.

Once the effect has worn off, you immediately suffer all levels of fatigue at once and you need +50% recovery time from normal.

Cancels out sleeping draught.

Philtre: once taken, the next person to communicate with you has 2d4 temp. Charisma (to you only) for the next 4+d4 turns.

Once the effect wears off, you can roll Intelligence to realise you were influenced. Even if you don't, prior low-regard for the influencer might be intensified by the sudden contrasts in Charisma.

This is no more effective that the friends spell.

Availability and distribution is clandestine, on a par with poison (and at least twice the price).

Spagyric: one dose will increase the effectiveness of 1 attribute of another pharmaceutical by 50%.

By itself, purgative.

Weird Alchemy.

The processes of extraction and production are jealously guarded secrets. 

Luminiferous Ether: two substances in a vessel that, when mixed, produce a light source as good as a jar of glow worms that fades over d4 turns.

If you pay more, you can get one guaranteed to last 3 turns.

It is not extinguished by exposure to water, nor lack of air. It is not fire, so unaffected by magic etc. working on that element.

Counterintuitively for some, it does not contain/require phlogiston.

Manna ('Drow Lembas'): alchemical food that is instantly destroyed by exposure to sunlight.

Exposed to air, but kept in darkness, properly wrapped, it will last 60 days before disintegrating. Eat it darkness or low light conditions, quickly.

Lightweight and nutritionally dense (equal to one day's ration), it is not appetising. The same property that prevents it being poisoned, putrefied or diseased (including parasites) means it cannot be seasoned.

Kept in an unopened packet it is good for a year.

Manna is not a cost effective way to feed oneself, let alone end world hunger.

*It can be fed to constructs/undead to quell their appetite for human flesh/life energy, if it seems appropriate in context.

*The process of creation exposes the Plague Doctor to mild radiation poisoning.

Miasma: the quintessence of disease. 

It has the general properties of stinking cloud cast at minimum level (3rd), plus exposure to the disease it is derived from.

Neutralised by universal solvent. 

Phlogiston: the quintessence of flammability. 

Exposed to air, it instantly burns up as bright flame, so can be used to dazzle or ignite low flash-point material. 

It is unstable and cannot be stored for any length of time or in quantity in its elemental form. 

Stored in airtight darkness, it deteriorates in 30+d20 days; 2d6 days once exposed to air and light.

Universal Solvent: discovered while attempting to develop a cheap substitute for holy water, this is a broad spectrum disinfectant, cleaning solution and weedkiller. 

Applied directly to a wound, it causes 1 hp lethal damage but will neutralise any disease in there. It will also neutralise parasites and poison if administered in time (if no rules for this, then no later than the end of the next round).

It inflicts d8 lethal damage to plant, filth and disease monsters.

It is a poison if drunk (min. effect purgative) but there's no way you could disguise it in food or drink (effectively putrefying it).

It can be used to purify water, but makes it poisonous.

Commentary.

Nothing here is meant to be as good as or to directly compete with magical healing. That's the point.

None of them are magical of themselves (i.e. they do not detect as such), but they probably require a magical background environment to exist.

All can be administered as pills, potions, injections, and liquid, smoke or powder pumped into various bodily openings. Some can be smoked, whether or not mixed with newly-discovered, precious, life-sustaining tobacco.

For some more pseudo-historical/thematically appropriate general medicine, plus henbane, opium, and all the other good stuff in the doctor's bag, I direct you to the Ghastly Affair Presenter's Manual.

Same overall acknowledgements for source material as for the Plague Doctor.

I always liked that the Citadel/Warhammer Plague Elemental was a sub-type of Air Elemental (and the Life and Death Elementals as sub-types of Earth) - at least until they were re-branded as daemons.

Tony Ackland/ L - R: Life, Death and Plague Elementals, plus Balrog (Baalrukh?)

Beowulf Rolls a 1

Wiglaf hearing about Beowulf's 1.
J.R. Skelton (1908)

Something of a shower thought, this one.

If a 20 is ruled/house-ruled as a crit, it often follows that a 1 is a fumble.

Very reasonably, higher level Fighters complain that this means they end up fumbling more often than less-skilled characters.

When a non-Fighter rolls a 1 to hit, it's a fumble, and they drop/break their weapon or wound themselves or trip over an imaginary invisible turtle.

When a Fighter rolls a 1, it's goddamn heroic:

• At 1st level, they break their weapon (causing normal damage) and all unlevelled and max. 1 HD/level monsters/NPCs who witness it must make a Morale Check.
• At 4th level, they break their weapon (full damage) and all max. 3 HD/level monsters/NPCs who witness it must make a Morale Check; unlevelled and lower than 1 HD/level NPCs/monsters auto-fail the Morale Check.
• At 8th level, they break their weapon (crit/double damage) and all max. 4+1 HD/level monsters/NPCs who witness it must make a Morale Check; all max. 3 HD/level monsters/NPCs auto-fail their Morale Check; unlevelled and lower than 1 HD/level NPCs/monsters auto-fail their Morale Check and must save or be rooted to the spot in awe/fear for d3 rounds.

Alternatively (or in addition), instead of the Morale Check on witnesses, you could bestow some later edition Barbarian Rage on the Fighter (1 round at 1st level-3rd level, 4 rounds at 4th to 7th, 8 rounds from 8th).

This should be enough to pull off a monster's arm or wield a giant-forged sword.

Magic weapons can be exempt from this rule, although I'm happy to see them shatter. Furthermore, the heroically shattered weapons of 4th and 8th level Fighters make suitable materials for making other magic items/weapons (cf. Narsil/Anduril).

As a general rule, if a monster can only be hit by special and/or magical weapons it's not likely to be affected mechanically even if the broken weapon is magical. 

At lower character levels and/or lower-magic settings, a non-magical weapon broken on a 1 could be ruled to cause to damage to otherwise invulnerable monsters and be eligible for re-forging as a magical weapon.

Commentary.

This is because of Beowulf, but he's not the only one to break a sword on the hero's journey.

Beowulf as foundational fantasy rpg text, via The Lord of the Rings, and as an OSR exemplar via The Eaters of the Dead/ The Thirteenth Warrior.

In a combat-focussed d20 system, this is going to happen often enough to add a dimension of the ridiculous - so you could either a) save it up for narratively significant fights or b) boringly make non-Fighters fumble on a 1, but Fighters only miss.

Not Quite Canon: BYAKHEE for Old School Fantasy & Horror

Byakhee/ Lisa Free

A re-model rather than a conversion; * for optional.

The TLDR/Basic Byakhee.

Hybrid winged things composed of conventional material. Summoned by mortal sorcerers as guardians and mounts. Called by cultists to receive sacrifices. 

Have the ability to probability travel anywhere in the universe in 1-12 hours. They cannot enter a planetary atmosphere this way, but they can leave - vanishing without trace.

They can carry a single adult human and their equipment on these journeys. They always arrive hungry.

Armour Class: As Leather.

Hit Dice: 4 (Medium/ Human-sized; wingspan comparable to Gargoyle or Harpy).

Movement: 50% of Normal Human on the ground; x2 Normal Human in flight in the lower atmosphere; x3 in upper atmosphere; x6 through space (if not using probability travel).

If carrying an adult human at the same time, reduce flying speed to x1 in lower atmosphere and x2 upper atmosphere. Encumbrance does not affect space flight or probability travel.

Attacks: 2 per round (all +1 for Strength):

• Claw/hoof/paw d3 damage.
• Bite/ram/slam d6 damage.
• Horn/spike/sting/tail d4 damage.

Special Attacks:

• If both claws hit, auto-bite or carry off (max. adult human) next round.
• If bite hits, can drain d3 pints of blood etc. per round. Will continue until you're empty, not just dead.
• If sting hits, save vs. venom as for Centipede, Giant. You will have nightmares of flight and space and cold *and Carcosa while sick.
• Swoop with surprise for double-damage; crit/natural 20 to carry off (max. adult human).
• Victims carried off can be dropped from height for falling damage.

Special Defences:

• Immune to cold (magical and normal), disease, poison, radiation, sleep and vacuum/asphyxia.
• *blink away (as Blink Dog) if it uses probability travel to escape.
• *can see invisible, ethereal, duo-dimensional and out-of-phase things.

*Spells: 40% chance of 1-4 spells. These can be blur, light, mage hand and minor illusion, if you like.

Morale: 9 (*10 vs. Mi-Go; 12 if commanded by Hastur).

Alignment: Neutral Hungry, or compatible with Hastur.

*Traditional association with Hastur as worshipper-servitors and co-inhabitants of Carcosa.

Grenadier Byakhee.

Advanced Byakhee.

They were not altogether crows, nor moles, nor buzzards, nor ants, nor vampire bats, nor decomposed human beings; but something I cannot and must not recall.

…hybrid winged things that no sound eye could ever wholly grasp, or sound brain ever wholly remember.

Bits in bold are more important than the rest of the description.

While Byakhee are composed of conventional material, they are not anchored in conventional space-time.

Not being anchored in conventional space-time means they exhibit certain characteristics of hyperspace entities. This accounts for the mortal inability to absolutely perceive their objective physicality; also the wild variations in size and appearance from encounter to encounter.

You do not wholly see Byakhee, you interpret them: ‘winged’ is an abstraction, much like ‘hound’ is for the tindalosi.

Byakhee visually de-code as devils, hippogriffs, bees, wasps, valkyries, youwarkees, skeletal butterflies with stone knives on their wings, harpies, imps, bats, angels, nightgaunts, tyranids, pterodactyls, pegasi, wyverns, star vampires, shantaks, flying polyps, jabberwockies, and -men (hat-, moth- and shadow-).

And they can also look like whatever you are primed for a Byakhee to look like (whether you've been reading The Festival or The House on Curwen Street).

Byakhee are immune to enlarge/shrink and polymorph. Neither can they be dismembered or decapitated. Certainly, not by mundane mortals.

They are affected by spells etc. as are summoned creatures - even in Carcosa.

Intelligence: Average (human-level), but rarely credited.

Telepathic and understand all languages, but communicate only in clicks, croaks, screams, squawks, squeals and whistles. Traditionally respond to whistled directions and simple commands.

Capable of mimicking a surprising range of sounds, including laughter, weeping, and incomprehensible muttering, as well as following (and formulating) complex plans.

They are unconcerned with the morality of actions they are bound/commanded to perform, as well as ethical concerns over their choice of sustenance. They mostly (privately?) find humans to be ridiculous things - fragile, limited, pliable.

Size: Roll d4:

1. Small: imp

• HD 1-1 (or d6 hp)
• 1 attack per round
• reduce damage dice increments by one step; no damage bonus for Strength
• drains 1 pint of blood in d6 rounds
• if sting hits, save vs. poison or d3 non-lethal/subdual damage
• Swoop with surprise for x2 damage, but cannot carry off targets

2. Medium: gargoyle

• as the Basic Byakhee
• if it's carrying you off, you are at -2 to hit it and score only minimum damage, but it is at -2 to hit you

3. Large: wyvern

• HD 6 to 7
• 3 attacks per round; can split between 2 targets
• +2 to damage for Strength/size
• does not drain blood, but auto-bites/continuous damage
• if sting hits, save or 0 hp/Casualty state
• can carry an armoured adult human without flying movement penalty
• Swoop with surprise for x2 damage; crit/natural 18-20 to carry off (max. armoured adult human)
• can carry off in its jaws as well as its claws
• if it's carrying you off, you are at -2 to hit it and score only minimum damage, but it is at -2 to hit you

4. Giant: dragon

• HD 10 to 12
• 4 attacks per round; can split between 3 targets
• +4 to damage for Strength/size
• does not drain blood, but auto-bites/continuous damage
• if sting hits, save or die and d3 acid splash damage to everyone within 5' of the target
• can carry up to three armoured adult humans without flying movement penalty
• Swoop with surprise for x2 damage; crit/natural 16-20 to carry off (max. armoured horse)
• can carry off in its jaws and tail as well as its claws
• if it's carrying you off, you are at -2 to hit it and score only minimum damage, but it is at -2 to hit you
• Morale +1

Their size changes relative to mundane mortals because they are arriving from fourth-dimensional hyperspace - the Byakhee is always the same size from its own perspective.

Armour Class: Roll d6:

1. Tough hide (as Leather)
2. Scaly hide (as Leather + Shield)
3. Chitinous (as Chain + Shield)
4. Hard carapace (as Plate)
5. Equivalent of descending Armour Class 0
6. Invulnerable Monster/ magic weapon to hit, and reroll for AC; any additional 6s increase the + of the weapon needed to hit

Tactile feedback does not necessarily correspond to visual expectation.

*Personal Reality Distortion: Roll d8 (except when encountered in space or Carcosa):

1. blurred (-4 to hit it the first time, then at -2 thereafter; Byakhee gets +1 to all saves)
   
2. displacement (it appears to be 3’ from where it actually is; -2 to hit it; Byakhee gets +2 to all saves)
   
3. duo-dimension (as the spell, but no portion of the Byakhee extends into or is vulnerable from the Astral Plane)
   
4. ethereal (can only harm and be harmed by other ethereal beings, but can use its spell-like abilities; can semi-materialise for feeding only; cf. Ghost)
   
5. gaseous form (as the spell, but can use its spell-like abilities; can semi-materialise for feeding only)
   
6. improved invisibility (-4 to hit, +4 to saves)
   
7. mirror image (recasts d6 rounds after images destroyed/dispelled)
   
8. statue (as the BECMI spell; the Byakhee cannot move except by probability travel, but gets AC equivalent to descending -4, plus immune to normal and magical fire; can use its spell-like abilities; can partially de-petrify for feeding only)

Stacks with and/or overrules Armour Class results.

Tactile feedback does not necessarily correspond to visual expectation. 

*Spells: 40% of 1-4 spells from this list (taken from A Ghastly Affair). Roll d10:

1. bewitch cattle

2. blacken sky

3. blast crops

4. change/steal gender (only 1 per day)

5. obtain oracle (on another's behalf)

6. protection from bullets/normal missiles (depends on milieu)

7. rain of blood/ fish/ frogs/ flesh/ shower of stones (only 1 per day)

8. raise storm

9. steal milk

10. witch’s mount (on another's behalf)

All spells are supplementary effects of the ability to probability travel - they detect as psionics rather than magic, but are vulnerable to dispel magic.

It can know spells other than these, and is able to grant a casting to, as well as perform them on behalf of, another - given the right incentives.

*The Black Man at the witches' sabbat is not Nyarlathotep.

Loic Muzy/ Byakhee vs. Shantak - not much between them, eh?

Space Mead.

Whatever space mead is and however it is made/obtained (sometimes a bee-like by-product of the Byakhee themselves), it is an absolute requirement for mortals accompanying Byakhee when they probability travel. As well as protecting the imbiber from the physical effects of space travel, it also places them in a hypnotic stupor that lasts until they arrive at their destination.

The journey takes 1-12 hours (depending on distance and/or random factors) for purposes of strict time records, but for anyone travelling without space mead it will be longer than you think and they must immediately retire the character on arrival at their destination, either dead or irrevocably, self-destructively insane.

There are theories as to why and what, but no-one alive knows for sure.

*Maybe space mead is only the best known and most widely available product for surviving probability travel with the Byakhee, and there could be rare/unique alternatives.

Erol Otus/ 1e AD&D Deities & Demigods

Commentary.

Visual shorthand is space bees and alien vultures. General consensus is that they're the things described in The Festival, but otherwise they're extrapolations in the Derleth-Petersen tradition.

I'm going to guess that they're not many people's Mythos favourites, but only the most fervent Lovecraft purist would leave them out of the bestiary - how else are you getting to Carcosa?

The RAW CoC rpg Byakhee is at the lower end of the threat range (for comparison, my conversion comes out at 3+3 HD, AC as Leather), and has no special defence against a hail of bullets, so you too could exterminate a genuine sapient extra-terrestrial in your own back yard with a few of your friends.

The Byakhee in A Happy Family (Adventures in Arkham Country). It's only pretending to be bound. I misremembered it as having chosen to do so for comfort and security - my foundation for their psychology.

Tiny B & W photograph of the Grenadier miniatures in White Dwarf had me de-coding Byakhee as winged humanoids, wearing beaded skirts and clawed gauntlets before I ever opened the CoC 2e rulebook.

In Biblical Carcosa, they de-code as Pre-Colombian Meso-American cyber-Skeksis.

A PLAGUE DOCTOR Class for Old School Fantasy & Horror.

The modern archetype - Plague Doctor from Darkest Dungeon (II) - a self-medicating, grenade-tossing, trailblazing young woman and general badass.

Approximately early edition D&D-ish system agnostic; * means optional. 

Description: A sub-class of the Assassin and the Cleric, the Plague Doctor is a pioneer and practitioner of scientific medicine in a world with magical healing, the harbinger of a scientific and technological revolution that will never come.

They seek to oppose and dismantle the exclusionary racket of magical healing (see 1e DMG pp. 103-104) - to replace it with their own rational and enlightened exclusionary racket based on cutting edge science (leeches, miasmas, humoral theory, astrology, phrenology, haruspicy etc).

Despite their alien appearance and grisly reputation (the traditional regalia is believed to date back to the first Plague Doctors who tended to the dying and tallied the dead when epidemic outpaced cure disease), Plague Doctors are serious professionals attempting to fill a gap in the landscape of healing.

Sometimes known as Leeches, Tallymen, or whatever their mask most resembles. They prefer you address them as Doctor or Master.

XP, attack matrix, saving throws:  As Cleric.

Hit Dice: d6 (*or 2d4 at 1st level, d4 each level thereafter for monastic Plague Doctors).

Prime Requisites: Dexterity and Intelligence.

Armour: Anything they like but it will hamper them as it would a Thief.

Plague Doctors prefer the distinctive and traditional uniform of their profession (equal to Leather plus closed helm, gauntlets and protective boots). Here's some unflavoured mechanics:

• Mask: Advantage/bonus to save vs. airborne disease, stench, smoke, poison gas, foul air etc. and/or doubles minimum safe time in those conditions. Also protects the eyes as (game) logic dictates.
• Surprise, listening and perception-type checks penalised by c. 20% due to restriction of hearing and peripheral vision. Can't detect anything by scent.
• You need to replenish the supply of medicinal herbs/neutralising substances in the mask daily and/or after exposure (1 unit of common currency every time) or the mask loses its protective properties.
• Depending on the tech level of the setting, the mask can be connected to an air pump or tank.
• Robes: Pre-modern hazmat suit. Advantage/bonus to save vs. splash, touch and other contact effects and/or doubles minimum safe time in applicable conditions.
• Protective, not indestructible.

Weapons: Knife and grenade-like missiles.

*Syringes, clysters and reinforced bellows for administering gaseous and liquid cures; surgical instruments (such as the cleaver, dagger, hand axe, and notched heavy cutting blade); firearms (for dispersing miasmas and frightening disease spirits); mancatcher, staff, club, spear, blackjack, net, whip, blowgun (for subdual and crowd-control); close range bolt guns (air, string, spring or powder) for administering end of life care. Flame-throwers. Burning oil and flaming torches. Poison and venom. Chloroform-soaked rag.

*Magic: Plague Doctors affect a pose of 1e Unearthed Arcana Barbarian detestation of magic (though they hold Clerics in lower regard than Magic Users).

But in reality they're not averse if it gives them an advantage, as long as they can plausibly ad/or stealthily deploy it while maintaining their public professional stance.

*XP awards for destroying magic items as part of their mission; incorporation of Barbarian First Aid to the Plague Doctor special ability.

Alignment: Any Evil - sub-class of the Assassin; in opposition to the healing gods.

The older, satirical archetype - Dr. Beaky.

Special Abilities.

Autopsy: Spend 2-4 hours (-1 turn for each level over 3rd; minimum 2 hours) dissecting and otherwise examining a corpse, and you have a 60% + 2% per level of accurately determining time and cause of death.

Sometimes cause of death is obvious/commonplace and will not need a roll/take the usual time. The older the corpse, the less accurate the results.

*% penalties if the corpse is non-human, non-humanoid and/or magical. Though you might learn something anyway.

Diagnosis: INT check to determine the medical problem (and the methods of treatment): mundane wounds, disease, poison, diet, age, madness etc. Cumulative +1 at 3rd, 6th and 9th level. Situational bonus or auto-success for having appropriate medical treatise/specialist diagnostic tools at hand. 

Sometimes the problem is obvious/commonplace and will not need a roll. Sometimes the doctor will make something up.

Sometimes the diagnosis cannot be made without communication and cooperation from the patient.

*In a magical world, a medical doctor may also be able to diagnose whether the problem is magical in nature, if not the specifics.

*Disadvantage/penalty if the patient is non-human, non-humanoid and/or magical.

First Aid: Term of convenience - tweak to suit your setting if it breaks immersion. This is bandaging or sewing wounds, applying ointment, irrigating, applying tourniquets, cauterising etc.

In combat, heal d3 with a DEX check; after combat, heal d4 without a check; within an hour, heal d2 (no check). 

It's a round action in combat, up to an exploration turn afterwards. You might need to make a check out of combat if you are under some other kind of pressure (e.g. field hospital under fire; ongoing natural disaster; demonic incursion; exam conditions; your patient is the king).

Max. once per per person per day at 1st level; twice at 4th level; thrice at 8th level. Only new wounds from combat or accident, not hp farming during downtime. Not cumulative with giving aid to 0 hp/Casualty state characters, or special assistance laid out in (e.g.) individual monster rules.

You can treat poison/venom up to the end of the round after it was administered (or within half the onset time, if using those rules), and you and the victim must sit out the next d4 rounds (d3 @ 4th level, d2 @ 8th). At the end, roll a new save. Success is equivalent to slow poison (1 hour/level). Max. per person per day as for First Aid.

*Nausea, sickness, stun, bleeding, choking, disease, parasitic infestation etc. could be treatable by a Plague Doctor in combat.

*Depending on the background logic of the setting, things such as Ghoul paralysis and lycanthropic transmission might also be dealt with this way. 

Kate Sherron. If you're in an Altered State, they look like moths/mothmen.

Knife Specialist: Automatically proficient at 1st level; automatically specialised at 4th level.

From 3rd level, you cause a bleeding wound on a crit or scoring 4 over the target number. 

A pint is lost every d3 rounds unless the wound is treated. Every pint past the 1st, lose one-third hp and 2 CON.

Only vs. approx. humanoid/human-sized targets with circulating blood.

You Backstab as a Thief of the same level.

*It might be cool to be able to use this on Vampires.

Languages: You are able to learn ancient/dead languages from 1st level.

If your INT is 15+, from 4th level you can learn the special languages of other alignments, druids, and thieves. 

In addition, if they exist in the setting, you can also learn the tongue of ghouls, the cant of grave robbers, the priestly languages of the cults of the dead and the undead.

This is to access obscure medical treatises and privately discuss treatment with reticent patients, so we are told.

Leechcraft (Bleeding): Remedial bloodletting, including application of leeches. It is recommended for a broad spectrum of disorders of the body, mind and soul.

Bleeding is rarely more than a few ounces at a time (max. damage = d3 non-lethal, d6 if you're prone to fainting). Otherwise, use rules for bleeding wounds.

It doesn't work.

Placebo Effect: Base 1% per level, plus your CHA modifier.

This is the chance an ineffective medicine or procedure has a beneficial material effect on the patient's condition.

*Further adjustments for renown of the remedy or the professional, expensive treatments, rare ingredients, how it's administered (e.g. placebo pills of different colour, placebo injections/enemas > pills, cutting you open, rummaging around and sewing you back up > injections), time spent, cultural factors, hypnotic suggestion etc.

Surgery: INT check, and the number rolled is the number of rounds/turns/hours of surgery, and the number of DEX checks you'll need to make. +1 bonus at 4th level; +2 at 8th.

If you roll a critical fail, you cause a bleeding wound and d6 appropriate Ability Score damage.

Every normal fail causes d3 lethal damage. Any surgery always cause min. d3 lethal damage.

If you succeed in all (or most, or enough) of your DEX checks, then the procedure was a success - but what does success look like in the pseudo-historical milieu of your choice?

As a starting point, think about what surgical procedures were carried out in the ancient to pre-modern period: trepanning (actually prehistoric), bone-setting, amputation (judicial and medical), circumcision, various degrees of castration, cataract removal, lancing and draining, abortion, cutting for the stone, a surprising amount of what we would now call reconstruction, aesthetic and remedial body-modification, prolonged torture.

Simple and commonplace procedures don't need multiple DEX checks, except if you want to roll for critical fails.

*Assistants, whether just an extra pair of hands or another trained professional, can improve chances of success and/or reduce the negative consequences.

*Transplants and grafts may be possible, if that works for the game/setting.

*This is also a Torture special ability - successful checks indicate the victim survives, not that they tell the truth.

The Vivisect - surgical possibility in a magical world. From The Talisman of Death. Art by Bob Harvey.

Thief Skills: You Pick Pockets, Move Silently, Hide in Shadows, Read Languages and Hear Noise as Thief of 2 levels lower (min. 1). You need to take your mask off to Hear Noise, unless using a stethoscope.

*You can never get one over on a Thief of the same (full/Plague Doctor) level as you, but you can an Assassin.

Treatment: Being cared for/treated by a Plague Doctor with at least basic kit/resources improves natural healing:

• +1 hp per day of normal activity (adventuring)
• +2 hp per day of light activity (downtime between adventures)
• +3 hp per day of complete rest (deliberately recuperating)
• +4 hp per day in an actual hospital (or equivalent)

In lieu of promoting natural healing, if the Plague Doctor makes an INT check, care/treatment allows a +2 to a save vs. disease or poison/venom, if allowed. +3 with access to decent medical supplies and conditions, +4 in an actual hospital (or equivalent).

Soft cap max. 6 patients per day (-1 hp for everyone for each patient over 6; penalty also applies to relevant supplies and ability checks).

*With assistants, decent medical supplies and ideal conditions you can offset some of the penalties for more than 6 patients.

*Concentrating on one patient at the expense of the others gives advantage/bonus for them, disadvantage/penalty for everyone else. If you only have one patient, you can't concentrate on them any more than you already are.

Actually Slough Throt, a skinless sorcerer from 2000AD's Slaine, but I think the character design illustrates another visual possibility, or one for a pseudo-historical time period significantly earlier than quasi-medieval/early modern. Art by Mike McMahon.

In Practice.

Research/Training.

You must perform dissections equal to your current/old level in order to progress to the next level.

If not, then:

• you do not gain a level (you do not lose the XP)
• all your ability checks, saves etc. for medical practice are at disadvantage/penalty
• lose specialisation bonus with knife; cannot inflict bleeding wounds
• no level bonus for autopsy (and roll at disadvantage/penalty)
• all treatment inc. First Aid only 50% effective

To regain these abilities, you need to do twice as many dissections as you failed to do.

Dissections must be of a intelligent humanoid cadaver and take 2-4 hours each (not including prep time; autopsy time saving for level doesn't count).

Autopsies carried out do not add to this total.

The Price of Knowledge.

In a magical setting, your explorations converge with those of the Necromancer, and intimacy with death elides with undeath. Meaning that you are vulnerable to arcane corruption.

*Ravenloft Powers Checks could also apply, or be used as an alternative corruption system.

10% chance at 3rd level, 30% at 4th. Otherwise, you get your first at 5th level, then one every level thereafter: roll d10. 

Everything advances a Stage on rerolls. Living Death trumps Cadaverous Appearance. Allergies will be to things that are hard to avoid in your professional practice, your darker nature, the façade of a normal life, adventuring.

1. Allergy: Stage 1: save vs. contact/exposure or -1 to all rolls for d4 turns per contact/turn of exposure; nausea (-2 all rolls) 1 day if consumed; Stage 2: auto-fail save vs. contact/exposure for -1 to all rolls for d6 turns per contact/round of exposure; sick as per Cave Locust spit if consumed. Stage 3: any contact/exposure and -3 to all rolls for d3 days; save or die if consumed.
2. Animal Aversion: Stages: -1, -3 then -6 Reaction Roll for animals and children; at Stage 3 any roll of doubles means carnivores attack, herbivores stampede.
3. Cadaverous Appearance: Roll d8 and count up the scale from Skeleton: that's the type of Pseudo-undead you're going to start resembling (min. 3 Stages).
4. Exposed to a Disease: Stage 1 is just a normal exposure (though most likely to be Mummy/Tomb Rot); Stage 2 is especially virulent/the previous exposure compromised your immune response - saving/recovery rolls at disadvantage/penalty; Stage 3 you'll always be a carrier - treat regularly to halt/reverse symptoms and prevent spread (*these might be two separate problems).
5. Living Death: Roll d8 and count up the scale from Zombie: that's the type of Undead you're going to start resembling (min. 3 Stages). Weaknesses, compulsions/diet/habits first, then immunities/resistances, then special abilities. You are Turned as a Special, but you are not fully undead until you die.
6. Morbidity: Stages: -1, -3 then -6 to Charisma, and cumulative +1 save vs. horror per Stage - so obsessed with wounds, disease, death, dying, surgery, questionable medical paradigms, and ethically-challenging thought experiments that you're not pleasant to be around.
7. Nocturnal/ Heliophobic: Stages -1, -3 then -6 as a Goblin/Orc vs. sunlight. In addition, at -3 you are also at disadvantage/penalty vs. light-based attacks; at -6, you gain dark-/infra-/night-vision, you auto-fail saves vs. light-based attacks and will be blinded until you recover for d4 hours in total darkness.
8. *Unholy Compulsion: Look up the Sacrifice table from the Necromancer class by Lew Pulsipher in White Dwarf issue 35 - this is your new (additional) dissection schedule. Same penalties for not doing these as Research/Training dissections, and you need to do twice as many to make up. Compulsive dissections do not count towards Research/Training. These are neither medically necessary nor possible to pass off as such.
9. Weakness/ Fatigue: +1 level of permanent Fatigue unless you take progressively more addictive, expensive and hard to source drugs.
10. Weakness/ Stat Damage: -1, -3 then -6 (d3) CON, DEX or STR, unless you take progressively more addictive, expensive and hard to source drugs.

If Unholy Compulsion as written is too strong a flavour, how about you pique the interest of the Order of the Gash, or the Practice (Book of Unremitting Horror/ Invasive Procedures for Fear Itself rpg) instead?

Another visual possibility. Art by Alberto Ponticelli.

What Was Left Out.

Masks: Different types and philosophies based on their masks/regalia.

Granbretan Beast Orders; various Egyptian deities (and Stargate); the Order of the Fly; Dream's Helm (from Sandman); Venetian/masquerade masks; the early masks/helmets of fire-fighters and diving suits; things that resemble bad taxidermy elephants, rabbits (floppy eared), ducks, foxes and koala bears; single and multiple tentacle-trunk-faces; ballooning throat pouches.

Hazmat Robes: straw raincoat-style, feathers, hair, hides (like Slough Throt), waxed cloth, oiled silk, monster skins, rubber.

Special Materials for Surgical Instruments: silver (anti-bacterial properties), obsidian (still used today), jade.

Specialists: the alchemists, the apothecaries, the alienists, the anatomists; warrior-surgeons and war criminals; actual assassins; medical martial artists; perfumiers.

Organisation: Practices, Colleges, Orders, Guilds. The infirmary; the hospital; the asylum; the sanatorium.

More in common with 1e AD&D Assassins and Monks gaining followers than a sensible community health recruitment policy.

How prestigious (as compared to folk and clerical healers)? Ancient establishment or recent disruptors?

Medicine: remedial and recreational (see the Apothecary and both Chiurgeons, below).

Apothecarial Arsenal: poison gas, Greek fire, smoke bombs, flash pellets, zombie powder, extreme hygiene flame throwers, a cheap alternative to holy water.

Anonymity/Secret Identity: That Plague Doctors rarely to never allow themselves to be seen unmasked or unrobed; that the regalia can take on the attributes of the wearer, that these can persist and be transmitted.

Commentary.

Someone's done Darkest Dungeon heroes for LotFP. The Plague Doctor is a Cleric with vial bombs and remove fear memorised. I think that's pretty good.

The Treatment special ability is mostly the Medicine NWP from 2e Masque of the Red Death. Because Medicine is better than Healing? (The Plague Doctors certainly think so)

Some of the other Plague Doctor homebrew out there: for B/X; 5e Darkest Dungeon conversions; for Ye Olde School Games (and Black Hack) - this one both minimalist and flavoured. 

The Apothecary and the Healer NPC classes from 2e's Sages & Specialists. The Apothecary is a minor Magic User with a laboratory for identifying and brewing potions, also a number of other interesting things (including stimulants and painkillers, as well as an aphrodisiac that makes you think your Charisma's raised and beauty cream that apparently underwrites their whole business). The Healer has a herb garden and can heal more people better by filling NWP slots with duplicates of Healing and Herbalism.

Andrew Wyatt's Chiurgeon class from the 2e Ravenloft Book of Secrets was a really useful foundation - thank you.

There's also a 3.5e prestige class (con)version (which I only just found while looking for the link to Wyatt's).

Both are more effective at what they do than my Plague Doctor, as they're more in the Victor Frankenstein/Dr. Moreau/Herbert West direction, whereas I'm leaning into the pseudo-historical - "the procedure was a success, but the patient died" - and extrapolation in an implied setting.

A Ghastly Affair has questionable medicines (including mercury for your syphilis) that would fit right in here. And drugs on the edge of medicine/magic which might also. And a bit of the Mad Scientist class.

Sub-class of the Cleric, because so is the Pulsipher Necromancer - a thematic ancestor.

Also ancestors, (barely) the dead alchemist from The Philosopher's Stone 1e AD&D scenario (White Dwarf #66) and (in outlook) the 1e AD&D Artificer class from White Dwarf #68.

Sub-class of the Assassin. It just seems appropriate - I originally wondered if I could use the 1e Assassination table for a medical procedure or something. 

(Table for payment by level of 1e Assassin vs. level of victim could be used to determine how much a Plague Doctor charges for how grand a patient)

Obligatory #BOSR reminder that the implied setting of D&D is an American one, right down to your expensive life-saving medical care being denied by an unassailable power.