Diseases

A plague devastates the kingdom, sending adventurers on a quest to find a cure. An adventurer emerges from an ancient tomb, sealed for centuries, and soon finds themselves suffering from a devastating disease. An arcanist offends some dark power and contracts a strange affliction that spreads every time they cast spells.

A simple outbreak might amount to little more than a small drain on the group’s resources, curable with lesser restoration. A more complicated epidemic can form the basis of one or more adventures, with the characters searching for a cure, stopping the disease’s spread, and dealing with its consequences.

A disease that does more than infect a few members of the group is, essentially, a plot device. The rules help describe the effects of a disease and how it can be cured, but the details of how a disease behaves aren’t bound by a common set of rules. Diseases can affect any creature, and a given disease may or may not pass between members of one origin or creature type and another. A plague might affect only constructs and the undead, or ravage an entire vastaya tribe while leaving other species untouched. What matters is the story you want to tell.

Disease Examples

The diseases here illustrate the range of ways they can act within the game. Feel free to change the saving throw DCs, incubation period, symptoms, and other traits of these diseases to suit your campaign’s needs.

Sewer Plague

Sewer plague is a generic term for a broad category of diseases that incubate in sewers, garbage heaps, and stagnant swamps, and are sometimes transmitted by the creatures that inhabit those areas, such as rats and raxinim.

When a humanoid creature is bitten by a creature carrying the disease, or comes into contact with filth or waste contaminated by the disease, it must succeed on a DC 11 Constitution saving throw or become infected.

It takes 1d4 days for the symptoms of sewer plague to appear in an infected creature. Symptoms include fatigue and cramps. The infected creature suffers one level of Exhaustion and regains only half the normal number of hit points from spending Hit Dice, and none from finishing a long rest.

At the end of each long rest, an infected creature can make a DC 11 Constitution saving throw. On a failure, the character gains one level of Exhaustion. On a success, the character’s level of Exhaustion decreases by one. If a successful save reduces the infected creature’s Exhaustion level below 1, it recovers from the disease.

Eye Rot

This painful infection causes bleeding from the eyes and eventually blinds its victim.

A beast or humanoid that drinks water contaminated by eye rot must succeed on a DC 15 Constitution saving throw or become infected. One day after infection, the creature’s vision begins to blur. The creature takes a −1 penalty to attack rolls and ability checks that rely on sight. At the end of each long rest after the symptoms appear, the penalty worsens by 1. When it reaches 5, the victim becomes Blinded until their vision is restored by spells such as lesser restoration or full heal.

Eye rot can be cured using a rare flower called Eyebright, which grows in certain swamps. Over the course of about an hour, a character proficient with an herbalism kit can turn the flower into a dose of ointment. Applied to the eyes before a long rest, one dose prevents the disease from worsening after the rest. After three doses, the ointment cures the disease completely.

Laughing Fever

This disease affects humanoids. While dealing with it, victims frequently succumb to fits of uncontrollable laughter, which gave the disease its most common name and also its morbid nickname: “the screams.”

Symptoms manifest 1d4 hours after infection and include fever and disorientation. The infected creature gains one level of Exhaustion that can’t be removed until the disease is cured.

Any event that causes the infected creature to suffer stress — including entering combat, taking damage, facing its fears, or having a nightmare — forces it to make a DC 13 Constitution saving throw. On a failure, the creature takes 5 (1d10) psychic damage and becomes Incapacitated by uncontrollable fits of laughter for 1 minute. The creature can repeat the saving throw at the end of each of its turns, ending the Incapacitated condition and the uncontrollable laughter on a success.

Any humanoid creature that starts its turn within 10 feet of an infected creature in the middle of a laughing fit must succeed on a DC 10 Constitution saving throw or also become infected with the disease. Once a creature succeeds on this saving throw, it becomes immune to that particular infected creature’s laughing fit for 24 hours.

At the end of each long rest, an infected creature can make a DC 13 Constitution saving throw. On a success, the DC to resist and to avoid a laughing fit drops by 1d6.

When the DC drops to 0, the creature recovers from the disease. A creature that fails three of these saving throws randomly gains a form of Madness for an indeterminate amount of time, as described in the Running the Game - Madness chapter.