VERISIMILITUDE: Adventurers who wade through sewers, sleep in dungeons, and fight rats should occasionally get sick. Disease grounds fantasy in consequence.
RESOURCE DRAIN: A party that can trivially heal combat damage faces new challenges when remove disease spells become precious resources.
ADVENTURE HOOKS: “The princess is dying of Moonblind – only tears from the Moon Goddess can save her” creates instant motivation.
ENVIRONMENTAL STORYTELLING: Different regions feel distinct when swamps carry Gloom Spores while mountain tombs inflict Fossil Creep.
TACTICAL DEPTH: Players must weigh risks. Do we explore that mummy’s tomb? Can our cleric spare the spell slot?
CHARACTER MOMENTS: How does the noble paladin react when afflicted with disfiguring leprosy? What happens when the wizard loses INT to Word Rot?
When NOT to Use Diseases
AVOID DISEASES IF:
Your players find bookkeeping unfun – disease tracking requires record-keeping
Your campaign is heroic power fantasy – diseases undermine power levels
You lack time for cure quests – diseases deserve resolution, not forgotten character sheets
Your table lacks trust – disease can feel like DM fiat punishment
Your game is already gritty enough – don’t pile misery on misery
SKIP DISEASE CHECKS WHEN:
The party just suffered major losses
Disease would derail important plot moments (use sparingly – consequences matter!)
It’s been less than 3 game-months since last disease incident
The affliction would be boring rather than dramatic
Disease as Drama vs. Disease as Punishment
GOOD USE – DRAMA: “You contracted Serpent’s Kiss from the yuan-ti priest’s dying curse. Your blood runs cold. The expedition into the frozen north just got complicated – but the Fire Lily growing there might cure you…”
BAD USE – PUNISHMENT: “You failed your save. You have Gutter Grit. You lose 1 STR and 1 CON per week until you get remove disease cast. Next?”
THE DIFFERENCE:
Drama creates story opportunities
Drama involves player choice and agency
Drama has interesting consequences beyond numbers
Drama offers multiple solutions (magical, mundane, exotic)
Punishment just removes numbers from the sheet
Punishment offers no choices
Punishment makes players feel helpless
GOLDEN RULE: Every disease should create at least one interesting decision or story opportunity. If it doesn’t, skip it.
II. CORE MECHANICS
Contraction & Exposure
When to Check for Disease
MONTHLY CHECKS (Routine): Roll once per game month during normal adventuring. This represents accumulated exposure to normal hazards.
WEEKLY CHECKS (Hazardous Conditions):
Very hot weather or hot, moist weather
Filthy, crowded conditions in warm weather
Swamp, jungle, or marsh exploration
Siege conditions or refugee camps
Extended dungeon delving (4+ weeks underground)
IMMEDIATE CHECKS (Direct Exposure):
Bitten by diseased creature
Drinking contaminated water
Eating spoiled or cursed food
Attacked by disease-carrying monster (mummy, rot grub, etc.)
Exposure to disease trap or environmental hazard
Sharing enclosed space with infected person for 1+ days
Triggering specific disease curse
Base Contraction Chances
STANDARD DISEASES: Base Chance: 2%
Modifiers:
Currently diseased or parasitically infested: +1%
Crowding (city, encampment, shipboard): +1%
Filth (garbage, sewage, poor sanitation): +1%
Character is old (age 50+): +2%
Marsh, swamp, or jungle environment: +2%
Hot and moist climate: +2%
Character is venerable (age 70+): +5%
Exposure to carrier of communicable disease: +10%
Cool weather or climate: -1%
Cold weather, high mountains: -2%
Shipboard after 2+ weeks at sea: -2%
PARASITIC INFESTATIONS: Base Chance: 3%
Modifiers:
Filth (garbage, manure, sewage): +1%
Improperly cooked meat: +2%
Polluted water: +5%
Swamp or jungle environment: +5%
Cool weather, desert climate: -1%
Cold weather, high mountains: -1%
MAGICAL DISEASES: These typically don’t use percentage chances. Instead:
Monster attack: Save vs. Poison/Death or contract disease
Cursed item: Automatic contraction, Save determines severity
Trap: Save as trap level indicates
Environmental: Exposure time determines automatic contraction
Constitution Modifiers to Disease Rolls
Apply AFTER determining base chance, when rolling for specific character:
Constitution
Occurrence Modifier
Severity Modifier
-2 and Under
+2
+2
-1
+1
+1
0
0
0
+1
-1
0
+2
-1
-1
+3
-2
-1
+4
-2
-2
Additional Modifiers:
Has chronic disease/disorder: +1 to both
Severe parasitic infestation: +1 to both
Under 25% of normal HP: +1 to both
Roll of 0 or less = no disease contracted
Occurrence Types
ACUTE (Single Attack)
Disease runs its course once and is done. Character either recovers or dies. Most common type.
Examples: Gutter Grit, Bog Lung, Dungeon Fever
Determination: Roll 1d6 when disease contracted:
1-3: Chronic
4-6: Acute
(Some diseases are always one or the other – noted in description)
CHRONIC (Recurring)
Disease becomes part of character’s system, recurring periodically. Each recurrence follows normal severity progression.
Recurrence Schedule:
Roll 1d6 months for first recurrence
Roll 1d4 months for subsequent recurrences
Stress, injury, or environmental triggers may cause immediate recurrence (DM discretion)
CRITICAL RULE: If two chronic diseases occur simultaneously, BOTH increase one severity level. Chronic Mild + Chronic Mild = both become Severe. This makes chronic diseases genuinely threatening.
SYMPTOMS: Character coughs up black spores, breath rattles wetly, fever develops.
MILD: Cannot perform strenuous activity. Disadvantage on physical checks. Each day make STR save or lose 1 CON (temporary). Duration 1d3 weeks.
SEVERE: Totally disabled 1d2 weeks, then mild 1d2 weeks. Lose 1 CON per day. Each severe attack has 10% chance of permanent CON loss. Coughing fits cause 1d4 damage.
TERMINAL: Death in 1d12 months. Character drowns in own fluids as lungs fill with fungal growth. At death, body releases massive spore cloud (20′ radius, all must save vs. Bog Lung).
CURE:
Smoking rare mushrooms (herbalism check) + bed rest halves duration
Remove disease cures immediately
Dry, clean air and sunlight gives +2 on saves
DUNGEON FEVER
Spread by rats, fleas, and contaminated water in underground ruins.
Contraction: Rat bites, flea bites, drinking stagnant dungeon water Occurrence: Acute (always) Severity: 1d6 System: Blood/General
SYMPTOMS: Alternating chills and fever, hallucinations, weakness, pale skin.
MILD: -2 to all rolls. Cannot perform strenuous activity. Duration 1d3 weeks with bed rest.
SEVERE: Disabled 1d2 weeks, then mild 1d2 weeks. -4 to all rolls. Hallucinations cause confusion (10% chance per hour of acting randomly for 1d6 rounds). HP reduced to 50% maximum.
TERMINAL: Death in 1d12 days from organ failure. Character suffers seizures, violent hallucinations (may attack allies), and internal hemorrhaging.
CURE:
Complete bed rest for one week in clean environment
Remove disease cures immediately
Herbal tea (wintergreen + yarrow) gives +2 on saves
Cool compresses reduce fever, halve duration
GRAVE TOUCH
Contracted from contact with undead or disturbing ancient burial sites.
SYMPTOMS: Flesh grows cold and gray, wounds won’t heal naturally, purple pustules form on neck and hands.
MILD: -2 to CHA. Commoners feel instinctively uncomfortable around infected. Wounds won’t heal naturally (magical healing works normally). Duration 1d3 weeks.
SEVERE: HP reduced to 50%. Disabled 1d2 weeks, then mild 1d2 weeks. Lose 1 STR and 1 CON per week. Magical healing only half effective. Skin looks corpse-like.
TERMINAL: Death in 1d12 days. Character becomes pale and cold, cannot eat or drink. 50% chance of rising as a wight 1d3 days after death.
CURE:
Touch of a true monarch (traditional cure)
Consecration by cleric + bathing in holy water for three nights
Remove disease works
Submersion in mercury (takes 2d6 damage but cures disease)
GUTTER GRIT
Common in cities – contracted from rat bites, spoiled food, or contaminated wells.
Contraction: Rat bites, spoiled food, contaminated city water Occurrence: Chronic (always) Severity: 1d6 System: Blood/Gastro-intestinal
SYMPTOMS: Blood thickens with toxins, severe digestive problems, vomiting, bloody stool.
MILD: Cannot perform strenuous activity, must rest. Chronic cases lose 1 STR and 1 CON per week until cured. Duration 1d3 weeks.
SEVERE: Lose 1 STR and 1 CON permanently. Disabled 1d2 weeks, hemorrhaging internally, vomiting blood. Then mild state 1d2 weeks recovery.
TERMINAL: Death in 1d12 weeks from organ failure and blood poisoning. Character cannot hold down food or water. Body expels blood from all orifices.
CURE:
Clean environment, herbal purges, and magical healing
Remove disease cures
Requires 1 week of clean water and fresh food after cure
RED AGUE
A blood disease carried by giant insects and stirges.
SYMPTOMS: Crimson splotches on skin, fever, joint pain, lethargy.
MILD: -1 to DEX per day (minimum 3). Cannot perform strenuous activity. Duration 1d3 weeks.
SEVERE: As mild, plus disabled 1d2 weeks, then mild 1d2 weeks. HP reduced to 50%. Lost DEX returns at 1 point per day after cure.
TERMINAL: Death in 1d12 weeks. Skin turns completely red. Blood becomes toxic – anyone drinking infected blood must save vs. poison or contract Red Ague.
CURE:
Herbal poultices (requires herbalism check) and enforced rest
Remove disease cures immediately
Lost DEX returns at 1 point per day
RUST LUNG
Industrial disease from mining operations, forge-work, or rust monster attacks.
SEVERE: 10% chance per occurrence to permanently lose 1 STR and 1 CON. Totally disabled 1d2 weeks, then mild 1d2 weeks. Chronic severe attacks accumulate losses. Coughing causes 1d4 damage per day.
TERMINAL: Death in 1d12 months from respiratory failure. Character drowns in oxidized fluids. Metal objects rust faster near them (1 week exposure ruins normal metal).
CURE:
Purified air, mountain rest, and heal spell
Remove disease stops progression but doesn’t restore lungs
SYMPTOMS: Flesh begins rotting from point of contact, spreading slowly. Smell of decay follows character. Wounds turn black.
EFFECTS:
Character immediately has STR drained by 1d3
Cannot heal naturally
Magical healing only half effective
Each day, lose 1 STR
At STR 0, character dies and rises after 1d6 days as a mummy
CURE:
Must be cured by remove curse or remove disease before STR reaches 0
Heal spell works
If STR reaches 0, only wish or resurrection can bring back (prevents mummy transformation)
LYCANTHROPY
Creatures who suffer from lycanthropy become able to change into a wereanimal form.
Contraction: Lycanthrope bite (failed save), cursed items, full moon rituals Occurrence: Chronic (always) Severity: Roll 1d6 (determines initial control) System: Special (transformation)
SYMPTOMS: After infection, 1 day incubation. After 2d6 days the infected character transforms fully and disease can no longer be healed with basic magic.
MILD (1-2): Character has good control. Can transform at will by taking 1 Stress.
SEVERE (3-5): Character has moderate control. Must save vs. WIS when wounded or stressed or transform involuntarily.
TERMINAL (6): Character has poor control. Transforms every full moon automatically and may transform when wounded (save at disadvantage).
LYCANTHROPY TRAIT: You can take Stress to turn into your wereanimal form by choice. While in wereform:
Immune to mundane weapons
Cannot cast spells or wield weapons
Only light armor survives transformation
+2 to STR and CON, +4 to damage
Natural weapons (bite/claws)
LOSS OF CONTROL: Whenever you suffer Wounds, whether in wereform or not, make WIS save to prevent losing control. If you lose control, you turn into wereform for 1 Turn and will attempt to indiscriminately slaughter those around you.
CURE:
Remove curse or remove disease works ONLY in first 2d6 days
After full transformation, requires wolfsbane potion drunk under new moon, or wish
Killing the lycanthrope that infected you sometimes works (50% chance)
KNUCKLE ROCK (Petrification Creep)
A disease that slowly locks up the infected’s joints and turns their skin to stone.
Contraction: Basilisk gaze (partial), medusa blood, cursed stone statues, primordial tar Occurrence: Chronic (always) Severity: 1d6 System: Bone/Connective Tissue
SYMPTOMS: One limb begins to stiffen and turn gray. Skin feels rough. Movement becomes painful.
MILD: One limb stiffens (roll randomly: 1-2 arm, 3-4 leg). Suffer Break on all DEX rolls. Movement reduced by 5′. Duration 1d3 weeks.
SEVERE: Disabled 1d2 weeks (stiffness spreads to torso), then mild 1d2 weeks. Lose 1 DEX per day as skin slowly turns to stone. HP reduced to 50%.
TERMINAL: Complete petrification in 1d12 weeks. Each week another body part turns to stone:
Week 1: One limb
Week 2: Second limb
Week 3: Third limb
Week 4: Fourth limb
Week 5+: Torso and head
At DEX 0 or full petrification, character becomes stone statue.
CURE:
Stone to flesh cast at exact moment of final transformation
Basilisk tears applied daily (halts progression)
Remove disease works if caught early (before 3 limbs affected)
SPELL BUG
A parasite which feeds on the affected character’s magic energy.
SYMPTOMS: Tiny ethereal insects visible only to spellcasters. Character feels mental “itching” when casting.
MILD: Take double Stress when casting spells. Always roll on Blunder table after casting. Duration until cured.
SEVERE: As mild, plus spell bugs eat character’s brain, draining 1 WIL per week. HP reduced to 50%. Character occasionally coughs up small white moths.
TERMINAL: At WIL 0, character becomes mindless vessel controlled by spell bug colony. Will seek out other spellcasters to infect. Death in 1d8 weeks unless WIL drain reaches 0 first.
CURE:
Remove curse + dispel magic cast simultaneously
Fasting from all magic for seven days (no casting, no magic items)
Consuming anti-magic field effect (risky – 50% chance of killing bugs, 50% chance of spreading them)
PURPLE-EYE FEVER
A fever which ravages the body’s immune system and colors the white of the eyes lavender.
SYMPTOMS: Eyes turn lavender, high fever, extreme weakness, vulnerability to everything.
MILD: Automatically fail saves against other diseases or poisons. When exploring dungeons or engaging in strenuous activity, roll 1d6 every Turn. On a 1, gain 1 Stress. Duration 1d3 weeks.
SEVERE: As mild, plus disabled 1d2 weeks, then mild 1d2 weeks. HP reduced to 50%. All damage taken increased by 50%.
TERMINAL: If not magically healed, fever runs its course after two weeks, but permanently reduces each attribute by 1. Character survives but is permanently weakened.
CURE:
Remove disease cures and prevents attribute loss
Heal restores lost attributes
If attributes already lost, requires restoration to recover
CHROMATIC CHILLS
A wizard’s disease born from mishandling unstable spell components.
SYMPTOMS: Body temperature fluctuates wildly with emotions. Glows faintly (random color).
MILD: When stressed, character glows (random color each time) and suffers 1d4 damage. Disadvantage on stealth. Duration 1d3 weeks.
SEVERE: As mild, plus WIS save each day or glow intensifies. HP reduced to 50%. At night, character’s dreams become visible as colorful auroras around them (30′ radius).
TERMINAL: Death in 1d12 days from thermal shock. Character alternates between burning (1d6 fire damage per hour) and freezing (1d6 cold damage per hour). Explodes in colorful burst at death (6d6 damage, 20′ radius, save for half).
CURE:
Bathing in moonlit water while dispel magic is cast
Remove disease works
Drinking liquid from a chaos elemental (rare)
CLOCKWORK CONSUMPTION
Contracted from ancient automaton workshops or clockwork dragon breath.
SYMPTOMS: Internal organs develop tiny gears and springs. Character makes clicking and ticking sounds. Movements become slightly mechanical.
MILD: Must wind self (special action, 10 minutes) each morning or suffer -2 to all physical actions. Cannot benefit from natural healing – only magical healing or mechanical repairs work (tinker’s tools required). Duration 1d3 weeks.
SEVERE: Character needs winding every 4 hours. Lose 1 CON and 1 DEX per week. When performing strenuous activity, must save or “jam” (lose action, take 1d4 damage from internal grinding). Disabled 1d2 weeks, then mild 1d2 weeks.
TERMINAL: Character has 1d12 weeks before complete mechanical transformation. At end, becomes a mindless clockwork automaton unless cured.
CURE:
Oil blessed by a technomancer or artificer
Remove curse + restoration
Immersion in anti-magic field for 24 hours (risky)
DREAM LEECH INFECTION
Parasitic thought-forms from the Ethereal Plane attach to victim’s dreams.
Contraction: Shared sleeping spaces with infected, dream-vapor traps, night hag attacks Occurrence: Chronic (always) Severity: 1d8 System: Brain/Psychic
SYMPTOMS: Character cannot rest properly. Dreams become violent and vivid. Dark circles under eyes.
MILD: Character cannot benefit from rest unless someone guards their dreams (requires full night watch by conscious ally). Lose 1 WIS per occurrence. Duration until cured.
SEVERE: Lose 1 INT and 1 WIS per occurrence. Dreams become real – each night, something from character’s nightmare manifests nearby (GM determines, usually hostile). Totally disabled 1d2 weeks (constant hallucinations), then mild 1d2 weeks.
TERMINAL: Death in 1d12 hours as dreams completely consume reality. Character’s mind fragments into multiple personalities, each fighting for control. At death, all nearby sleepers must save or contract Dream Leech Infection.
CURE:
Entering character’s dreams and defeating the dream leeches in psychic combat
Remove curse + heal
Dreamcatcher woven by a lunar elf
Never sleeping again (character becomes afflicted with permanent exhaustion after 1 week)
FOSSIL CREEP
Contracted from disturbing ancient burial grounds or touching primordial tar pits.
SYMPTOMS: Character’s bones begin turning to stone, starting from extremities. Skin becomes rough and age-marked.
MILD: One limb stiffens. -2 DEX, movement reduced by 5′. Cannot perform strenuous activity. Duration 1d3 weeks with treatment.
SEVERE: Lose 1 STR, 1 DEX, 1 CON permanently per month afflicted. Disabled 1d2 weeks (cannot move without help), then mild 1d2 weeks. Chronic severe attacks accumulate – character slowly becomes statue. Joints crack audibly.
TERMINAL: Complete petrification in 1d12 weeks. Character transforms into a fossil. Only stone to flesh cast at exact moment of final transformation can save them.
CURE:
Daily massage with rare oils (halts progression)
Remove disease works if caught early
Stone to flesh reverses advanced cases
Time travel to before infection (extremely dangerous)
MOONBLIND
Caused by staring at magical moons, lunar curses, or selune moth swarms.
SYMPTOMS: Eyes develop silvery film. Under moonlight, character sees everything in silvery monochrome.
MILD: -2 to vision-based checks. Under moonlight, character sees in strange silver vision. Cannot rest under moon (counts as no sleep). Duration 1d3 weeks.
SEVERE: Totally disabled 1d2 weeks (functionally blind except under moonlight), then mild state 1d2 weeks. Under moonlight must save or be completely blinded, staring at moon unable to act.
TERMINAL: Permanent blindness in one or both eyes (50/50 chance). Eyes turn completely silver and reflective. Character can only see during full moon (and then sees everything in painful detail, giving terrible visions).
CURE:
Tears of a moon goddess
Regenerate restores lost sight
Never looking at the moon again (wear blindfold at night)
Making peace with lunar deity
SERPENT’S KISS
Mystical affliction from snake cultists, yuan-ti venom, or serpent god curses.
SYMPTOMS: Blood becomes cold and reptilian. Character becomes cold-blooded, skin begins scaling.
MILD: Character becomes cold-blooded – sluggish in cold weather (-2 to all rolls below 60°F). Must rest, cannot perform strenuous activity. Chronic cases lose 1 STR and 1 CON per week until cured. Duration until cured.
SEVERE: Lose 1 STR and 1 CON per week until cured. Totally disabled 1d2 weeks (hypothermic even in normal temperatures), then mild 1d2 weeks. Skin begins scaling (lose 1 CHA per week, 10% chance permanent).
TERMINAL: Death in 1d12 days from complete metabolic transformation. Character becomes cold-blooded reptilian creature (save vs. polymorph to resist). Tongue splits, scales cover body completely.
MILD: Lose 1 random language (temporary). Cannot perform strenuous activity. Cannot cast spells with verbal components reliably (50% failure). Duration 1d3 weeks.
SEVERE: Lose 1 INT and 1 DEX per occurrence until cured. Totally disabled 1d2 weeks (cannot communicate at all, incoherent babbling), then mild 1d2 weeks. Chronic cases lose languages permanently. Character speaks in word salad.
TERMINAL: Death in 1d12 hours from brain hemorrhage. All language ability destroyed – character forgets how to think in words, loses all INT, reduced to animal intelligence.
CURE:
Heal spell + learning to speak again from scratch (takes months)
Speaking with a sphinx and answering riddle correctly
Wish restores immediately
True name magic (risky)
EXOTIC AFFLICTIONS
PETRIFICATION CREEP
(See Knuckle Rock above – same disease, different name)
SHADOW WASTING
Contracted in the Shadowfell or from wraith attacks.
SYMPTOMS: Character’s shadow begins to fade. Feels disconnected from reality.
MILD: Shadow lightens each day until disappearing (1d6 days). While fading: disadvantage on saves vs. shadow/darkness effects. Duration until cured.
SEVERE: As mild, plus when shadow is gone: character casts no shadow and suffers 1d4 damage per hour in direct sunlight. HP reduced to 50%. Disabled 1d2 weeks, then mild 1d2 weeks.
TERMINAL: At shadow’s complete disappearance, character begins fading into Shadowfell. Becomes translucent. Death in 1d12 days as character becomes shadow themselves (transforms into shadow creature).
CURE:
Defeating the creature that infected you (shadow returns immediately)
Remove curse cast at dawn
Sewing new shadow to feet (requires shadow from willing donor)
Traveling to Shadowfell and reclaiming shadow (dangerous quest)
SONG OF THE SIREN
Magical compulsion from harpy songs or enchanted music boxes.
Contraction: Harpy song, siren call, cursed music boxes, bard curses Occurrence: Acute (always) Severity: 1d6 System: Brain/Compulsion
SYMPTOMS: Character hums tune constantly. Cannot sleep properly. Obsessed with reaching water.
MILD: Hums constantly (disadvantage on stealth). Cannot sleep properly (count as one level of exhaustion). Duration 1d3 weeks.
SEVERE: As mild, plus each day WIS save or become convinced must reach specific body of water to sing properly. At water, will attempt to walk in unless restrained. Disabled 1d2 weeks, then mild 1d2 weeks.
TERMINAL: Character will stop eating, drinking, and sleeping to reach the water. Death in 1d12 days from exhaustion/dehydration or drowning. Character sings hauntingly at death (all who hear must save or be affected by Song of the Siren).
SYMPTOMS: Spellcasting causes character to vomit coins. Terrible magical nausea.
MILD: Each time casting a spell, must make CON save or vomit up 1d20 copper pieces (lose equivalent GP from belongings or take 1 damage per missing coin). Vomiting takes 1 round. Duration until cured.
SEVERE: As mild, but:
After 4th level spells: vomit silver pieces
After 7th level spells: vomit gold pieces
After 9th level spells: vomit gems Lost wealth is permanent unless collected (disgusting). HP reduced to 50%.
TERMINAL: Each spell cast causes 1d6 damage from violent vomiting. Character cannot keep down food. Death in 1d12 weeks from starvation/internal damage. Body becomes magical conduit – valuable metals pour from corpse.
CURE:
Fasting from all magic for seven days (no spells, no magic items)
Wish spell (ironic – might trigger final vomiting)
Remove curse + greater restoration
Completing quest for archmage who laid the curse
HOARD SICKNESS
Transmitted through cursed treasure or dragon breath.
MILD: Must make WIS save to give away or spend any coins/gems. Each day, save or steal something shiny from party or NPCs. Duration until cured.
SEVERE: As mild, plus skin develops metallic scale-like patches (1 AC bonus per week infected, up to +3). Must sleep atop possessions or suffer exhaustion. Will attack anyone approaching “hoard.” Disabled 1d2 weeks (arranging and counting treasure obsessively), then mild 1d2 weeks.
TERMINAL: After one month, character begins full draconic transformation. Sleeps atop hoard 20 hours per day. Attacks any who approach. Death in 1d12 months – transforms into small dragon-like creature, losing all sentience.
CURE:
Giving away ALL wealth and possessions (very difficult for afflicted)
Remove curse
Dragon’s forgiveness
Defeating and looting a dragon (ironic – 50% chance of worsening disease)
INK PLAGUE
Spread through cursed books or attacks by living ink creatures.
SYMPTOMS: Black veins spread across skin like spilled ink. Obsessed with writing.
MILD: Wisdom-based checks at disadvantage. Each day, character must spend 1 hour writing or suffer 1d4 WIS damage. Writings become increasingly bizarre. Duration until cured.
SEVERE: As mild, plus writings covered in strange glyphs that move and writhe. Lose 1 WIS per day. Disabled 1d2 weeks (writing constantly, covering every surface), then mild 1d2 weeks. Skin turns parchment-like.
TERMINAL: At WIS 0, character becomes a living book – their skin covered in constantly-shifting text containing all knowledge they ever possessed. Body flattens and stiffens. Death in 1d8 weeks.
CURE:
Burning a book bound in white leather under a full moon
Remove curse + restoration
Never reading or writing for one month (very difficult)
Having skin tattooed entirely in protective runes
PARASITIC INFESTATIONS
BONE WEEVILS
Microscopic parasites that burrow into skeletal structure.
Contraction: Contaminated bone dust, undead attacks, ancient burial sites Occurrence: Chronic (always) Severity: 1d8 System: Bone
SYMPTOMS: Faint clicking sounds from inside body. Bones become hollow and brittle.
MILD: Character hears clicking (disadvantage on perception checks from distraction). Each week, make STR save or suffer permanent -1 to STR as weevils hollow out bone mass. Duration until cured.
SEVERE: As mild, plus sudden impacts may cause bones to shatter – take additional 1d6 damage from any source of physical trauma. Lose 1 STR per week (permanent). Disabled 1d2 weeks, then mild 1d2 weeks.
TERMINAL: At STR 3 or lower, any physical shock causes catastrophic bone collapse. Death in 1d8 months. At death, thousands of weevils pour from corpse (20′ radius, all must save).
CURE:
Drinking solution of fermented vampire dust
Remove curse works but bones remain weakened (restoration needed)
MILD: Must eat twice normal rations or suffer exhaustion. -1 to CON. Cannot perform strenuous activity. Duration until cured.
SEVERE: Lose 1 STR and 1 CON per occurrence (permanent from severe attacks). Vomits up worms occasionally (horrifying). Disabled 1d2 weeks, then mild 1d2 weeks.
TERMINAL: Worms multiply exponentially. Death in 1d12 weeks from internal damage. At death, character’s body bursts with hundreds of worms.
CURE:
Anti-parasitic herbs (successful healing check)
Remove disease
Drinking alcohol for one week straight (Constitution checks required)
SYMPTOMS: Character forgets small details. Occasionally coughs up small white moths.
MILD: Each day, forget one piece of information (DM’s choice – name, face, recent event). After one week, lose proficiency in one random skill. Duration until cured.
SEVERE: As mild, plus after two weeks, begin forgetting languages (one per week). Character occasionally coughs up white moths that dissipate in sunlight. Others who touch these moths experience random memories from infected.
TERMINAL: After 1d12 weeks, character forgets who they are entirely. All memories gone, INT reduced to 3. Becomes blank slate. Body produces hundreds of moths containing all lost memories.
CURE:
Drinking tea made from elephant tears and never-forget flowers
Contraction: Earth elemental exposure, stone giant territories, petrification magic backlash Duration: 2d6 days System: Skin
EFFECTS:
Skin hardens to stone-like texture
+2 AC
-1 DEX
Advantage on saves vs. petrification
Sink in water (cannot swim effectively)
Skin appears gray and craggy
Fades naturally. Some stone masons consider it a blessing from their patron deities.
V. RUNNING DISEASES AT THE TABLE
Tracking Disease Progression
The Disease Sheet
Create a simple tracking sheet for each diseased character:
CHARACTER: _________________
DISEASE: ___________________
OCCURRENCE: Acute / Chronic
SEVERITY: Mild / Severe / Terminal
DAY/WEEK: _____ (track progression)
ABILITY LOSSES: STR ___ DEX ___ CON ___ INT ___ WIS ___ CHA ___
SYMPTOMS: _________________________
CURE PROGRESS: _____________________
NOTES: ____________________________
Session-by-Session Management
AT START OF SESSION:
Review all active diseases
Roll progression (if weekly/daily checks needed)
Apply ability score losses
Describe symptoms briefly
DURING SESSION:
Remind players of penalties when relevant
Describe symptoms during dramatic moments
Note when conditions worsen (stress, injury, poor environment)
AT END OF SESSION:
Update disease progression
Mark any treatment received
Note if cure quest initiated
Time Management
DON’T:
Roll disease checks every single day in real-time
Bog down game with constant tracking
Make players calculate everything
DO:
Abstract time between adventures (“Two weeks pass…”)
Roll disease checks at dramatically appropriate moments
Use disease as scene transition (“As you recover from Bog Lung over the next week…”)
Player Agency & Cure Quests
Give Players Choices
Every disease should present decisions:
IMMEDIATE CHOICES:
“Do we use our last remove disease now or save it?”
“Can we afford three weeks of bed rest?”
“Should we seek the healer or continue the mission?”
STRATEGIC CHOICES:
“Do we accept this quest for the Fire Lily cure?”
“Should we risk the dangerous surgery?”
“Can we find an alternative to restoration‘s cost?”
Designing Cure Quests
SIMPLE CURE QUEST (1-2 sessions):
Objective: Obtain specific rare component
Location: Nearby dangerous area
Obstacle: Single major challenge
Example: “Fire Lily grows on northern glacier. Yeti guards it.”
MODERATE CURE QUEST (3-4 sessions):
Objective: Multiple components or complex ritual
Location: Journey to distant land
Obstacles: Multiple challenges, rival seekers
Example: “Need vampire dust (from vampire), moonlight water (from Moon Temple), and blessing (from hermit sage in mountains)”
COMPLEX CURE QUEST (5+ sessions):
Objective: Legendary cure requiring epic journey
Location: Multiple exotic locations
Obstacles: Major antagonists, moral dilemmas, impossible choices
Example: “Only the Fountain of Life can cure your terminal Void Rot. It lies in the City of Brass in the Elemental Plane of Fire. The Efreeti Sultan controls access…”
Turn weakness into strength (exploit beneficial side effects)
Balancing Lethality
The Lethality Scale
LOW LETHALITY (Heroic Fantasy):
Most diseases are Mild or Severe, rarely Terminal
Remove disease readily available
Cure quests short and achievable
Ability loss mostly temporary
Use diseases for color and resource drain
MEDIUM LETHALITY (Standard OSR):
Mix of all severity levels
Remove disease limited but obtainable
Some cure quests required
Permanent losses possible but rare
Use diseases as significant threats
HIGH LETHALITY (Gritty/Hardcore):
Terminal diseases common
Magical healing rare or expensive
Most cures require quests
Permanent losses frequent
Transformations permanent
Use diseases as major campaign elements
Adjusting Difficulty
TO INCREASE DIFFICULTY:
More Terminal results
Faster progression
Higher cure costs
Multiple diseases simultaneously
Limited access to magic
TO DECREASE DIFFICULTY:
More Mild results
Slower progression
Cheaper/easier cures
Fewer chronic diseases
Available magical healing
When to Pull Punches
CONSIDER REDUCING SEVERITY IF:
Player already dealing with major setback
Character concept relies on threatened ability
Party lacks resources for cure
Disease would end character permanently without player input
It’s just not fun anymore
HOW TO REDUCE GRACEFULLY:
“Your Constitution is high – the disease doesn’t progress this week”
“The healer recognizes this strain – she can help for reduced cost”
“You find ancient text describing an easier cure method”
“The disease enters remission (Chronic goes dormant)”
Disease-Based Adventures
Adventure Seeds
THE PLAGUE TOWN: Party enters quarantined town. Must discover source of mysterious plague while avoiding infection. Cure lies in abandoned temple in town center.
THE CURSED ARTIFACT: Party member picks up cursed idol, contracts exotic disease. Curse can only be broken by returning idol to original tomb and appeasing ancient spirit.
THE LYCANTHROPE DILEMMA: Party member becomes lycanthrope. Must choose: seek cure, learn to control it, or accept transformation. Rival lycanthrope pack wants to recruit them.
THE HEALER’S PRICE: Only one person can cure party member’s terminal disease – an evil wizard who demands terrible price (kill innocent, retrieve dangerous artifact, etc.).
THE EPIDEMIC: Disease spreads through city. Party must track source, find cure, distribute remedy before entire population dies. Political factions interfere.
THE TRANSFORMATION: Character’s disease doesn’t kill – it transforms (clockwork, stone, shadow). Quest becomes about preventing/accepting transformation before deadline.
Sample Adventure: THE MUMMY’S CURSE
SETUP: Party loots ancient tomb. Fighter touched by mummy, contracts Mummy Rot. Has 2 weeks before STR reaches 0.
ACT 1 – DISCOVERY (1 session):
Fighter’s STR drops 1d3 immediately
Local priests can’t cure (beyond their power)
Research reveals only Pharaoh’s Scepter can cure Mummy Rot
Scepter is in possession of rival adventuring party
ACT 2 – THE RACE (2 sessions):
Chase rival party across desert
Fighter loses 1 STR per day (time pressure mounting)
Encounters with desert dangers, hostile tribes
Catch up to rivals at entrance to Second Tomb
ACT 3 – THE TOMB (1 session):
Fighter now at low STR, getting desperate
Uneasy alliance with rivals (or combat)
Navigate deadly tomb traps
Face guardian mummy
Retrieve Scepter
CLIMAX:
Fighter at STR 2 or 1
Use Scepter to cure rot
Decision: keep Scepter or give to rivals who also need it?
COMPLICATIONS:
Rivals are actually sympathetic, also trying to save friend
Scepter has limited charges
Using Scepter awakens ancient evil
Fighter’s player might actually want to become a mummy (undead PC!)
VI. DISEASE CREATION TOOLKIT
Building Your Own Diseases
Step-by-Step Process
STEP 1: CONCEPT What’s the core idea? One sentence:
“Disease that makes you forget words”
“Infection that turns flesh to crystal”
“Parasite that feeds on magic”
STEP 2: SOURCE How is it contracted?
Environmental (swamp, desert, cold)
Creature (specific monster)
Magical (curse, wild magic)
Mundane (poor hygiene, contamination)
STEP 3: SYMPTOMS What does it look like? Pick 2-3 vivid details:
Visual (color changes, growths, transformations)
Auditory (coughing, clicking, voices)
Behavioral (compulsions, personality changes)
STEP 4: MECHANICAL EFFECTS What does it do in game terms?
Choose system affected:
Blood/Bone: STR and CON loss
Brain: INT and DEX loss
Respiratory: STR and CON loss
Special: Unique effect
STEP 5: OCCURRENCE Acute or Chronic?
Acute: Single attack, cures or kills
Chronic: Recurring threat
STEP 6: SEVERITY Roll 1d6 or 1d8?
1d6 for standard diseases
1d8 for more lethal
STEP 7: PROGRESSION How fast does it worsen?
Slow: Per week
Medium: Per day
Fast: Per hour
STEP 8: CURE How can it be cured? Give multiple options:
Easy: Remove disease works
Moderate: Requires specific component
Hard: Requires quest
Extreme: Requires rare magic or acceptance
Example Creation
CONCEPT: “Disease that makes flesh transparent”
SOURCE: Exposure to ghosts, ethereal plane
NAME: Ghostflesh
SYMPTOMS:
Flesh becomes transparent and insubstantial
Can see organs and bones through skin
Feel disconnected from physical world
SYSTEM: Special/Transformation
OCCURRENCE: Chronic (1d6: 1-3 Chronic, 4-6 Acute)
SEVERITY: 1d6
EFFECTS:
MILD: Hands and arms become translucent. -1 to STR as flesh weakens. Advantage on stealth. Duration 1d3 weeks.
SEVERE: Half of body transparent. Lose 1 STR and 1 CON per week. Can accidentally phase through objects (10% chance when grasping). HP reduced to 50%. Disabled 1d2 weeks, then mild 1d2 weeks.
TERMINAL: Complete transparency in 1d12 weeks. At STR 0 or full transparency, character becomes ghost.
CURE:
Eating solid food blessed by cleric for seven days
Remove disease works if caught early
Restoration reverses transparency
Embracing ghosthood (become ghost PC – DM discretion)
Themed Disease Tables
UNDEAD DISEASES (d8)
Roll
Disease
System
1
Mummy Rot
Connective tissue
2
Grave Touch
Cardiovascular
3
Tomb Dust Fever
Respiratory
4
Ghoul Fever
Blood/Transformation
5
Spectral Wasting
Special/Shadow
6
Lich Touch
Brain/Necrotic
7
Bone Curse
Skeletal
8
Death Chill
Cardiovascular
ELEMENTAL DISEASES (d8)
Roll
Disease
Element
1
Cinder Lung
Fire
2
Frost Creep
Cold
3
Stone Rot
Earth
4
Storm Sickness
Air
5
Rust Plague
Metal
6
Sap Blight
Wood
7
Acid Blood
Acid
8
Lightning Nerves
Lightning
FEYWYLD DISEASES (d6)
Roll
Disease
1
Feybloom
2
Pixie Pox (uncontrollable shrinking)
3
Satyr’s Curse (compulsive revelry)
4
Hag Hex (aging acceleration)
5
Fairy Ring Rot (mushrooms grow from skin)
6
Glamour Sickness (appearance shifts constantly)
PLANAR DISEASES (d10)
Roll
Disease
Plane
1
Abyss Corruption
Abyss
2
Celestial Burning
Mount Celestia
3
Limbo Madness
Limbo
4
Shadow Wasting
Shadowfell
5
Feywild Bloom
Feywild
6
Infernal Contract Plague
Nine Hells
7
Astral Drift
Astral Plane
8
Ethereal Fade
Ethereal Plane
9
Far Realm Taint
Far Realm
10
Elemental Flux
Elemental Planes
Regional Disease Lists
SWAMP/MARSH DISEASES
Common in wetlands, marshes, bayous:
Gloom Spores (fungal, respiratory)
Swamp Rot (skin, bacterial)
Bog Lung (respiratory, fungal)
Blood Flukes (parasitic)
Marsh Fever (viral, similar to malaria)
Leech Curse (magical, blood-draining)
Contraction Modifier: +3% disease, +5% parasites
DESERT DISEASES
Common in arid regions:
Desert Fever (dehydration-based)
Sand Madness (brain, heat stroke)
Scorpion Venom Sickness (toxic)
Dune Mummy Rot (undead curse)
Sun Blindness (eye affliction)
Thirst Curse (magical, water dependency)
Contraction Modifier: -1% disease, but specific diseases more common
ARCTIC/MOUNTAIN DISEASES
Common in cold regions:
Frost Creep (freezing transformation)
Mountain Sickness (altitude, respiratory)
Yeti Plague (magical cold disease)
Ice Madness (brain, isolation)
Snow Blindness (eye, temporary)
Hibernation Curse (magical sleep)
Contraction Modifier: -2% disease, but exposure is major threat
URBAN DISEASES
Common in cities:
Gutter Grit (sewers, rats)
City Pox (crowding)
Plague (epidemic)
Dungeon Fever (poor sanitation)
Guild Rot (occupational diseases)
Noble’s Gout (rich food disease)
Contraction Modifier: +2% in cities, +4% in slums
JUNGLE DISEASES
Common in tropical forests:
Jungle Fever (parasitic)
Vine Rot (fungal, grows vines from body)
Monkey Madness (primate-borne)
Carnivorous Plant Spores (plant-based)
Heat Delirium (temperature)
Poison Dart Sickness (toxin)
Contraction Modifier: +3% disease, +5% parasites
UNDERGROUND DISEASES
Common in dungeons, caves, Underdark:
Gloom Spores (fungal)
Dungeon Fever (general)
Mine Lung (dust, respiratory)
Cave Blindness (light deprivation)
Deep Madness (isolation, brain)
Stone Sickness (mineral exposure)
Contraction Modifier: +2% disease, more with poor ventilation
QUICK REFERENCE TABLES
DISEASE SEVERITY QUICK TABLE
Roll 1d6 when contracting disease:
Roll
Severity
HP
Duration
Ability Loss
1-2
Mild
Normal
1d3 weeks
Temporary, -1/week
3-4
Severe
50%
2-4 weeks
Often permanent, -1/week
5-6
Terminal
Varies
Days to months
Permanent, rapid
CURE COST REFERENCE
Cure Type
Gold Cost
Availability
Herbal remedy
10-50 gp
Common
Professional healer
100-500 gp
Towns
Remove disease scroll
300-600 gp
Cities
Hire cleric
500-1000 gp
Cities
Heal scroll
1500-3000 gp
Rare
Restoration
1000 gp + components
Rare
Quest cure
Variable
DM determines
TREATMENT EFFECTS
Treatment
Effect
Bed rest
Halves mild duration
Proper care
Prevents severe→terminal
Herbal remedy
+1 to +2 on saves, reduces duration 25-50%
Magic healing
Restores HP only, not disease
Remove disease
Cures most diseases immediately
Heal
Cures all diseases + HP
Restoration
Restores 1 lost ability point
APPENDIX: SAMPLE DISEASES BY ALPHABET
A
Abyss Corruption (planar)
B
Berserker’s Blood (beneficial)
Bog Lung (mundane)
Bone Weevils (parasitic)
C
Carnival Plague (magical)
Chromatic Chills (magical)
City Pox (environmental)
Clockwork Consumption (magical)
D
Demon Itch (exotic)
Desert Fever (environmental)
Dream Leech Infection (magical/parasitic)
Dungeon Fever (mundane)
E
Echo Sickness (exotic)
F
Feybloom (magical)
Fossil Creep (magical)
G
Ghostlung (magical)
Gloom Spores (environmental/magical)
Grave Touch (mundane)
Gutter Grit (mundane)
Gut Worms (parasitic)
H
Hoard Sickness (exotic)
I
Ink Plague (exotic)
Ironblood Fever (beneficial)
J
Jabberwock’s Tongue (exotic)
Jester’s Curse (magical)
Jungle Fever (environmental)
K
King’s Evil (exotic)
Knuckle Rock (magical)
L
Labyrinth Vertigo (exotic)
Lycanthropy (magical)
M
Memory Moths (parasitic)
Mirror Sickness (magical)
Moonblind (magical)
Mountain Sickness (environmental)
Mummy Rot (magical)
P
Petrification Creep (exotic)
Prophet’s Palsy (beneficial)
Purple-Eye Fever (magical)
R
Red Ague (mundane)
Rust Lung (mundane)
S
Sea Plague (environmental)
Serpent’s Kiss (magical)
Shadow Wasting (exotic)
Siege Sickness (environmental)
Song of the Siren (exotic)
Spell Bug (magical)
Stone Skin Pox (beneficial)
Swamp Rot (environmental)
T
Timerot (magical)
Tomb Dust (environmental)
V
Void Rot (exotic)
W
Wild Magic Rash (magical)
Wizard’s Bane (exotic)
Word Rot (magical)
Wyrdlung (magical)
FINAL NOTES FOR THE DUNGEON MASTER
The Golden Rules of Disease
Make it Dramatic, Not Drudgery: Every disease should create story opportunities, not just bookkeeping.
Player Agency Matters: Always give players choices and paths to cure.
Respect the Tone: Adjust lethality to match your campaign’s feel.
Be Flexible: Pull punches when necessary, but maintain consequences.
Use Sparingly: Disease is a spice, not the main course.
The best disease in your game isn’t the deadliest – it’s the one that creates the most memorable story. The party rushing across the desert to find the Fire Lily before the fighter succumbs to Serpent’s Kiss. The wizard struggling with Word Rot while trying to decipher the final scroll. The paladin choosing between accepting lycanthropy or seeking the dangerous cure.
These are the moments players remember years later.
Use this guide as a toolkit, not a rulebook. Modify, invent, and adapt to serve your table’s fun.
