23

Deadly Disease

The world, for all its occasional beauty, is a filthy place. Monsters aren't the only threat to your survival—plague and disease stalk the land, destroying villages and decimating cities. Sometimes the greatest threat isn't the wild dragon—it's the child with a cough.

This chapter provides rules on catching and treating contagious diseases, and a selection of pre-made diseases to use in your game.

What is a Disease?

A disease is some form of ongoing sickness that causes harm to your character and, potentially, spreads to those around you—such as flu, chickenpox, or plague.

Diseases become more severe over time, progressing through 4 stages—so try to stay healthy.

InfluenzaTouch, Air · DC 10

Disease, Common2 days

A harmless cough and a slight fever can quickly turn into something much more serious without bed rest.

Effects
Stage Effect
1 You have a bad headache and a runny nose. You have -2 INT, and -2 WIS.
2 Your entire body aches and your throat is sore. You have -2 STR, -2 DEX, and -2 CHA.
3 You have a terrible fever and hallucinations. You cannot move under your own power.
4 Your internal organs fail and, after slipping into a coma, you die within a few hours.
Cured You have an annoying cough for one week.

Contracting Disease

Adventuring is not a clean business. Filthy sewers, rabid animals, rusty swords—there are countless ways in which a person might contract a debilitating disease.

There are three basic steps to follow when dealing with disease: contact, incubation, and first symptoms.

Step 1. Contact

First, your character needs to come into contact with an active disease. There are four ways this might happen:

  • Direct Contact: You touch an infected person or diseased fluid—such as blood, sweat, or pus.
  • Indirect Contact: You touch something that has been contaminated with a diseased substance or fluid—a doorknob, a shared bed, a knife.
  • Bites: Something bites you—a fly, a tick, a leech—and injects the disease directly into your body.
  • Consumption: You eat/drink something that's been contaminated—foul water, moldy bread, rotten meat.
  • GM:As you lean over the corpse to unclasp the necklace, Viridian, the zombie's stomach bursts with a sickening pop. Roll a Dexterity saving throw.
  • Viridian:Son of a... (rolls 3) ...damn zombies.
  • GM:Black ichor and pus splatter you in thick, wet clumps. The smell of rotten flesh is overwhelming.
  • Viridian:Gross. This can't be good.

Once your character has come into contact with a contagious disease, there is a chance of infection—the incubation period automatically begins.

Step 2. Incubation

All diseases have an incubation period—a period of time where, infected or not, you display no symptoms. At this stage, you have no idea if you're actually infected yet—all you can do is wait and hope for the best.

Step 3. Infection

Once the initial incubation period has passed, it's time to see if your character was infected and displays any symptoms. Make a Constitution saving throw against the DC of the disease—this is called an Infection check:

Success: You are not infected.

Failure: The disease has infected your body and you begin to display the first symptoms.

  • GM:During your week in town, Viridian, you notice you've developed a small cough. It's inoffensive, but persistent. Make a DC 10 Constitution saving throw.
  • Viridian:Damn it... (rolls 8).
  • GM:One morning, as you wake from a particularly fierce cough, you notice some thick green phlegm in your handkerchief. It smells foul.
  • Viridian:The flu? Again? Every. Time. I. Swear. Where's a cleric when you need them...

Wounds and Multiple Exposure

If you had any open wounds when you were exposed to the disease—or you were exposed multiple times—it becomes much more likely that you were infected. Make your Infection check with disadvantage.

Living with Disease

Once your disease starts to display symptoms, the battle begins. A runny nose, a splitting headache, a bad cough—manage your pain as best you can while you fight back.

Escalation

Periodically, your disease will try to attack your body and spread further. Each time the incubation period passes, make a Constitution saving throw to see if your disease changes—this is called an Escalation check:

Success: Your symptoms have peaked. Your disease improves by one step and goes into decline.

Failure: Your disease worsens by one step.

  • GM:After another week of illness, Viridian, you feel your symptoms begin to change. Roll a DC 10 Constitution saving throw.
  • Viridian:Fingers crossed... (rolls 18) ...finally.
  • GM:Your fever has broken at last, and you think you're over the worst of it now. Your flu is in decline.
  • Viridan:Great. Now who can I cough on...

First-Aid & Bed Rest

If you are treated with the appropriate first-aid, medicine, or bed rest during your illness, you can make your next Escalation check with advantage.

Decline

Once your symptoms have peaked and gone into decline, you automatically succeed every subsequent Escalation check until the disease finally leaves your system.

Relapse: If you come into contact with the disease again, you risk a relapse. Your illness stops its decline—make your next saving throw as normal to see if your disease escalates.

Recovery

You have managed to recover from your disease—well done. But some diseases may leave a lasting effect on your body—marks, scars, weakness—and you may also still be contagious to others at this point, so be careful.

Spreading Disease

Most diseases are highly contagious—once you have one, it's very easy to pass it on to someone else. There are two main ways you can pass on a disease while you are contagious: by touch and through air.

Touch

Your blood, sweat, and spit are rife with sickness. Anyone who makes physical contact with you while you are contagious risks infection. Things you touch with your bare skin—door handles, cutlery, tools—also become contaminated and remain so for an hour.

To avoid making accidental contact when touching someone who is diseased—for example, when administering first aid—make a DC 15 Intelligence or Wisdom saving throw. Wearing gloves, medical robes, and other protective gear can help defend against contamination—make your check with advantage.

Air

As you breathe, cough, and sneeze, the air around you becomes thick with sickness. Anyone that comes within 5ft of you is at risk of infection. Additionally, if you spend an hour in an enclosed room, it becomes contaminated and remains so until an hour after you leave—proper ventilation and thorough cleaning can help prevent this.

By wearing a face mask, you can minimize the spread of your airborne sickness by trapping coughs and spittle. However, wearing a basic mask or holding your breathe offers no protection against infection—disease is still able to infect you via your eyes and skin.

  • GM:The guard blocks you at the door to the lord's chambers, Clanda. "Sorry ma'am, Lord Marin has ordered us not to let anyone in. Personal matters."
  • Clanda:Ugh, I don't have time for this. I cast Friends and order him to let me pass.
  • GM:The guard pulls a hasty salute, his resolve temporarily weakened by your magic—"Yes ma'am, at once". He opens the door and you step forward into the lord's dark chambers.
  • Clanda:Why is it so dark in here?
  • GM:The curtains are drawn, and the air is thick and sickly. Lying in bed, coughing wetly, is Lord Marin. He opens one red eye. "You... should not... be in here."
  • Clanda:Oh you stupid lord, why didn't you say you were sick! I'll open the windows quickly to air out the room. If I fall ill, I swear I'll murder him.

Becoming Contagious

You are contagious once your hit points are below a certain threshold—this represents you bleeding slightly, or breathing harder, or sweating more. The more severe the spread of your disease, the more of a risk you become to other people.

When you take damage, check the Spreading Disease table to see if you become contagious or not.

Becoming Contagious

Severity Contagious
Stage 1 Less than 25% hit points remain
Stage 2 Less than 50% hit points remain
Stage 3 Less than 75% hit points remain
Stage 4 Always contagious

Death

If you die from a disease, your corpse becomes a breeding ground for your sickness. Your body remains contagious for the next week.

This goes for any corpse, so be careful of touching the dead—you never know what disease they may carry.

Diagnosis

When you contract a disease, it's not always obvious what you have from the first symptoms alone. Many diseases share similar symptoms at the beginning—headaches, fevers, rashes—so you may want to get your sickness diagnosed to prevent any nasty surprises.

To make a diagnosis, roll a Wisdom or Intelligence check against the rarity of the disease. You must be trained in Medicine. A Healer's Kit will also prove useful, granting advantage on your diagnosis attempt.

Diagnosing Disease

Rarity DC Description
Common 10 A frequent occurrence
Rare 20 Sporadic with sudden outbreaks
Mythic 30 A unique or magical sickness

Magical Healing

Magic is a great tool for healing the body, but it is not infallible—the body is a complicated, delicate machine. When you use magic to remove a disease, the sickness is not immediately purged but instead goes into decline.

Magic Strength

Not all magic is powerful enough to fight every disease. When using a spell or effect to treat sickness, compare the spell level to the disease DC to see if it will work.

Magic Strength

Spell Level Max DC Examples
0-5 15 Lesser Restoration, Lay on Hands
6-8 25 Heal
9 30 Mass Heal

Magical Immunity

Some class features may grant immunity to diseases—such as a paladin's Divine Health. In these cases, your immunity is not absolute—the resistance depends on the level of the effect (class level, item level, spell level, etc.).

Magical Immunity

Level Immunity
01-05 Diseases up to DC 15
06-10 Diseases up to DC 20
11-15 Diseases up to DC 25
16-20 All diseases

Disease Compendium

There are many diseases out in the world—some a mild inconvenience, some an almost-certain death sentence.

This section details a number of example diseases, and includes guidance on creating your vile illnesses.

Creating a Disease

To surprise your players with a sickness unique to your world, follow these steps to brew your own diseases.

Step 1: Rarity

First, decide how well-known the disease is in your world—common, rare, or mythic. The more common the sickness, the easier it is to make a correct diagnosis.

Step 2: DC

Next, decide how contagious the disease is. The higher the DC, the harder it is to resist the disease—use a small DC if you want characters to recover quickly.

When deciding on the DC, consider any rare items that your characters might need to hunt for to overcome their sickness—rare flowers from the Fetid Swamp, crushed dragonbone from the Ancient Graveyard, or a horse's heart from the Yellowgrass Plains.

Disease DC

Description DC
Easy to recover from, most people will only be ill for a short time before they fight it off. 05 / 10
These diseases hang around for a while, and most people will need to consider bed rest or some medicine to help them get better. 15 / 20
These diseases are almost impossible to recover from. Most people have no chance at stopping this sickness and can only accept their fate if no actual cure is possible. 25 / 30

Step 3: Incubation

Now choose how long the disease takes to escalate in severity. The longer the period, the longer it will be before any first symptoms start to show.

Step 4: Transmission

Next, pick how your disease is transmitted. Usually this is through touch or air, but there may be other triggers.

The GM is creating a mythic, magical disease that spreads through sound—resonant flux. This unusual disease is transmitted through audio waves whenever an infected person says the word "symphony".

Step 5: Stages

Now it's time to decide on the specific effects of your disease. Every disease has 4 stages, each increasing in severity. Describe the physical effects, and assign a mechanical penalty of some kind.

Effects are cumulative, so be careful not to assign too many effects at each step. At the same time, avoid having stages with no mechanical effect.

These are some effects you might like to consider:

  • -1/-2 to an ability modifier.
  • Fall into a coma, or death.
  • Reduced movement, or total paralysis.
  • Advantage or disadvantage on certain rolls.
  • Halve your speed.
  • Vulnerability to certain damage.
  • Lose some or all of your hit dice.
  • Gain a level of exhaustion.

Step 6: Cure

Finally, decide on any lingering effects on recovery from the disease—scars, weakness, immunity, etc. This is a good way to leave a lasting mark on characters and NPCs—even recovery has a price.

Diseases

Name Description Rarity DC Inc. Transmission
Bubonic Plague Horrible buboes spread across the body Rare 25 1 day Touch
Chickenpox Tiny, itchy spots spread across the body Common 20 2 days Touch, Air
Cholera Diarrhea and dehydration Common 10 1 day Touch (excrement)
Diphtheria A bad throat infection that can permanently scar the skin Rare 15 3 days Touch, Air
Dysentery Stomach cramps and vomiting Common 20 1 day Touch (excrement)
Influenza Fatigue, headaches, and fever Common 10 2 days Touch, Air
Smallpox Large, pus-filled spots cover the body Rare 15 4 days Touch, Air
Stonescale The skin turns grey and cracked, and the mind turns feral Mythic 30 4 weeks Touch
Syphilis A persistent fever that eventually attacks the mind Common 20 4 weeks Touch (sore)
Tapeworm A parasite that feeds inside the body causing weight loss Common 15 1 week Touch (excrement)
Typhoid Fever A bad fever and diarrhea Common 15 1 week Touch (excrement)
Whooping Cough Coughing fits violent enough to break bone Common 15 1 week Air

Bubonic PlagueTouch · DC 25

Disease, Rare1 day

Often mistaken for influenza at first, swollen buboes mark the body and a near-certain death sentence.

Effects
Stage Effect
1 Your body aches and you have a slight fever. You have -2 to all ability modifiers.
2 Painful buboes appear around your arm, groin, and neck. You have disadvantage on all rolls.
3 Your fever burns extremely hot and you can't stop sweating. You fall into a coma.
4 Your internal organs fail and you die.
Cured Your body is scarred by the buboes.

ChickenpoxTouch, Air · DC 20

Disease, Common2 days

Tiny, itchy spots that spread across your entire body. Very contagious, but not usually life-threatening.

Effects
Stage Effect
1 You have a slight fever and feel weak. You have -2 STR and -2 DEX.
2 You have noticeable pox marks across your body. You have disadvantage on all social checks.
3 You are covered in itchy spots. You have disadvantage on concentration checks.
4 Your fever is burning hot. You have disadvantage on all rolls.
Cured You have a few small scars from the pox. You are permanently immune to chickenpox.

CholeraTouch (excrement) · DC 10

Disease, Common1 day

One drink of bad water and you'll be curled up by the toilet for a week—or die from dehydration.

Effects
Stage Effect
1 You feel sick and nauseous, and eating food causes you to vomit. -2 DEX and -2 WIS.
2 You have diarrhea. -2 STR, -2 CHA, and you gain thirst at twice the normal rate.
3 You have lost noticeable weight. You are dehydrated and have disadvantage on all rolls.
4 Your body goes into shock from severe dehydration, and you die.
Cured You can't eat rich food for the next week without being sick.

DiphtheriaTouch, Air · DC 15

Disease, Rare3 days

A nasty infection of the throat that can cause permanent scarring if it penetrates the skin.

Effects
Stage Effect
1 You have a sore throat and headache. You have -2 CHA and disadvantage on concentration checks.
2 You have swollen glands in your neck and it's very painful to swallow. You have -2 STR and -2 DEX.
3 Large, painful ulcers appear on your skin. You have -2 CON and disadvantage on social checks.
4 Pus-filled blisters appear on your legs, hands, and feet. You have disadvantage on all rolls.
Cured You have permanent scars from your skin ulcers.

DysenteryTouch (excrement) · DC 20

Disease, Common1 day

Easy to catch and painful to endure, one sip of dirty water can be enough to ruin your whole week.

Effects
Stage Effect
1 You suffer painful stomach cramps. You have disadvantage on all saving throws.
2 You have a mighty need to use the restroom. You have -2 to all ability modifiers.
3 You can't keep any food down. You gain thirst and fatigue at twice the normal rate.
4 Your body is too weak to stand. Your speed is reduced to 0.
Cured You can't eat rich food during the next week without being sick.

InfluenzaTouch, Air · DC 10

Disease, Common2 days

A harmless cough and a slight fever can quickly turn into something much more serious without bed rest.

Effects
Stage Effect
1 You have a bad headache and a runny nose. You have -2 INT, and -2 WIS.
2 Your entire body aches and your throat is sore. You have -2 STR, -2 DEX, and -2 CHA.
3 You have a terrible fever and hallucinations. You cannot move under your own power.
4 Your internal organs fail and, after slipping into a coma, you die within a few hours.
Cured You have an annoying cough for one week.

SmallpoxTouch, Air · DC 15

Disease, Rare4 days

Tiny spots that quickly become large, painful blisters across your entire body, leaving you with pox scars.

Effects
Stage Effect
1 You have a slight fever and feel weak. You have -2 STR and -2 DEX.
2 You have a persistent headache and flat, red spots on your face, hands, and forearms. You have -2 INT, -2 WIS, and -2 CON.
3 Your spots become large, painful, pus-filled blisters. You have disadvantage on all rolls.
4 Your fever is extremely hot. You fall into a coma.
Cured You have severe scars from the pox.

StonescaleTouch · DC 30

Disease, Mythic4 weeks

As your skin turns grey and cracked, your mind decays to that of a wild animal. Kill them before they kill you.

Effects
Stage Effect
1 The skin around your eyes turns noticeably grey. You have disadvantage on social checks.
2 Your skin is grey and cracked. Movement is painful. You have -2 to all ability modifiers.
3 You become very forgetful and increasingly aggressive. You have advantage on all STR rolls, and disadvantage on all INT, WIS, and CHA rolls.
4 You have lost your mind and become a wild beast.
Cured Your skin is permanently marked with stonescale.

SyphilisTouch (sore) · DC 20

Disease, Common4 weeks

The flesh is weak. Let your guard down for one night and you might still be paying for it years later.

Effects
Stage Effect
1 A highly-contagious sore opens near your lips or groin. You have disadvantage on social checks.
2 A rash appears on your hands and feet, and you have a fever. You have -2 DEX and -2 CON.
3 More sores appear on your body, and you are easily exhausted. You have -2 STR and gain fatigue at twice the normal rate.
4 You have lost noticeable weight and your mind is fuzzy. You have -2 INT, -2 WIS, and -2 CHA.
Cured You still carry the disease and can infect others.

TapewormTouch (excrement) · DC 15

Disease, Common1 week

Tiny parasites that hide away in rotten meat and excrement. Watch what you eat.

Effects
Stage Effect
1 You always seem to be hungry. You gain hunger at twice the normal rate.
2 You have lost a significant amount of weight. You have -2 CON and -2 STR.
3 You suffer from terrible headaches and some memory loss. You have -2 INT and -2 WIS.
4 The parasites have reached your brain. You fall into a coma and die.
Cured You have painful stomach cramps for one week.

Typhoid FeverTouch (excrement) · DC 15

Disease, Common1 week

Sometimes it's better to go thirsty than take a drink of filthy water. Don't risk it—boil it.

Effects
Stage Effect
1 You have a fever, a headache, and frequent nosebleeds. You have -2 to all modifiers.
2 Red spots appear on your skin and you are easily exhausted. You gain fatigue at twice the rate.
3 You suffer diarrhea. You gain thirst at twice the rate and have disadvantage to all social checks.
4 Your fever is burning hot and you are delirious. You cannot move or act on your own power.
Cured You feel fragile for the next week.

Whooping CoughAir · DC 15

Disease, Common1 week

Fits of violent coughing followed by a 'whooping' inhale of breathe—and sometimes, broken ribs.

Effects
Stage Effect
1 You have a mild cough and disadvantage on concentration checks.
2 You cough in loud, uncontrollable fits with a gasping inhale. You have -2 STR and -2 DEX.
3 Your coughing fits are violent enough to cause vomiting. You have disadvantage on all rolls.
4 Your cough is so violent you have broken some of your ribs. You have 0 hit dice and cannot move without immense pain.
Cured You have an annoying cough for the next week.

Contents