Diseases (En Publishing)

First, decide if the illness you are creating is mundane or supernatural. This choice will inform the disease’s three components: transmission method, symptoms, and cure. Mundane components mimic those found in the real world, and supernatural components are the kind that can only happen in a fantasy game. A supernatural disease can have mundane components, but it must have at least one supernatural component.

Transmission Method

A transmission method is the way a disease infects creatures.

Mundane diseases can be airborne, foodborne, contact, and intimate. Contact diseases are spread by interacting with other creatures via skin to skin contact and intimate diseases require more than a handshake (like drinking from the same glass or kissing).

Supernatural transmission methods include spells, attacks of certain monsters, alchemical products, and exposure to foreign planes.

When a creature is exposed to a disease’s transmission method, it is allowed a saving throw to resist being infected. Most diseases require a Constitution saving throw, but some supernatural diseases which affect the mind could require an Intelligence, Wisdom, or Charisma saving throw. Marginally contagious diseases require a DC 10–11 save, moderately contagious diseases require DC 12–15, and highly contagious diseases require DC 16–20. If a disease has a transmission method which guarantees a lot of exposure, such as airborne, consider giving its saving throw a lower DC so all your PCs don’t take a week off from adventuring to fight the flu instead of orcs.

Note any specific creatures who might be immune to the disease. Immunity could be random and unexplained in very rare cases. In areas where a disease is most prevalent, some creatures have developed an immunity over the ages, while others carry the disease, but never experience its ill effects. Part of a disease’s transmission method is an incubation period. Most diseases need time to infect a target before symptoms appear, usually a few hours to a few weeks. Keep incubation periods shorter than a month, otherwise you might forget a PC is infected.

Symptoms

Most diseases have multiple symptoms which increase in severity if untreated. Mundane diseases have typical symptoms like coughing, sneezing, and vomiting while supernatural diseases have otherworldly symptoms like limbs turning into jelly or growing tentacles.

Assign symptoms a mechanical effect. A disease which causes a creature to vomit uncontrollably imposes levels of exhaustion, representing the creature’s growing dehydration. Mechanical effects for diseases include increased exhaustion levels, reduced hit point recovery, penalties to attack rolls, saving throws, ability checks, and AC, conditions, slowed movement, spell effects, and madness.

Some diseases have deceptive symptoms at first which actually give creatures a mechanical bonus before imposing a penalty.

Think about the disease’s end effect when creating symptoms. Death, indefinite madness, a permanent condition such as blindness, or transforming into another creature entirely could be the final result of an illness. Let that end effect inform the disease’s symptoms. For example, a supernatural disease that transforms a creature into an ooze might first reduce the creature’s movement and penalize its Dexterity saving throws as it becomes more lethargic and ooze-like.

Cure

Most diseases play out in a series of saving throws. With every success the symptoms get better, but with every failure they worsen. To encourage teamwork and camaraderie, a GM may grant a PC advantage on a saving throw if one of their allies succeeds on a DC 15 Wisdom (Medicine) check to care for the infected character during a long rest.

Diseases sometimes have another cure beyond this series of saving throws. Spells, alchemical treatments, environmental cures (like bathing in a specific spring), special creatures (the touch of an angel), or a combination of these could cure disease even after a creature has entered the disease’s end state.

Mundane Diseases

Bottle Fever

Disease, Mundane

Drinking putrid ale, wine, or liquor can mean more than a hangover. Creatures who catch bottle fever feel drunk even when they haven’t had any alcohol, because the yeast from a previous bad drink sticks to the walls of their stomachs and continues to ferment.

A creature who drinks rancid alcohol must succeed on a DC 12 Constitution saving throw or contract bottle fever. The first symptoms of bottle fever begin to show in 1d10 hours. An infected creature gives off a strong alcoholic odor. When the creature performs a physically exerting act, like climbing a wall or fighting, it must succeed a DC 10 Constitution saving throw or become poisoned for 1 hour. If the creature succeeds on the saving throw, it does not need to make another saving throw for this effect for 1 hour.

At the end of each long rest, an infected creature must make a DC 12 Constitution saving throw. If the creature fails three of these saving throws, the yeast become embedded in its stomach and the disease can only be cured by drinking a potion of supreme healing. If the creature succeeds on three of these saving throws, the disease is cured.

Itching Insides

Disease, Mundane

Itching insides is a respiratory disease surface-dwelling creatures can catch in damp underground areas or by coming into contact with another creature infected with the disease. Creatures who normally live underground, like drow and dwarves, are immune to itching insides.

A surface-dwelling creature who has spent a continuous week in a damp underground area or who has come within 10 feet of an infected creature must succeed a DC 15 Constitution saving throw or contract itching insides. The first symptoms, coughing and feeling itchy inside the lungs, appear in 1d4 days.

As the disease progresses, an infected creature begins to cough up a black mucus and the itching in its lungs turn to burning. The creature gains one level of exhaustion and whenever it performs a physically exerting act, like casting a spell or taking the Dash action, it must succeed a DC 11 Constitution saving throw or fall prone as it is overwhelmed by shooting pain in its lungs.

At the end of each long rest, an infected creature must make a DC 15 Constitution saving throw.

On a failed save, the creature gains one level of exhaustion and the DC to save against falling prone from pain during physical exertion increases by 1. On a successful save, the creature’s exhaustion decreases by one level and the DC to save against falling prone from pain during physical exertion decreases by 1. If a successful saving throw reduces the infected creature’s level of exhaustion below 1, the disease is cured.

Walking Rot

Disease, Mundane

Walking rot is an urban plague feared by city dwellers everywhere. It is a festering skin disease which causes flesh to fall off an infected creature’s bones, is highly infectious, and has a long incubation period. By the time a victim starts showing signs of walking rot, that person has already infected many others. Elves, gnomes, and fey are immune to this disease, though no one knows why. As a result, communities experiencing an outbreak of the disease seek out those creatures for aid.

A creature who has touched another infected with the disease must succeed on a DC 15 Constitution saving throw or contract walking rot. If a person who dies while infected is raised as an undead creature, they are able to pass walking rot on to anyone who touches them. The first symptoms take 1d4 weeks to appear. An infected creature’s skin takes on a bright red rash which bleeds when touched. The creature’s hit point maximum is reduced by 1d10. As the disease progresses, the skin turns black and the creature’s flesh begins to fall off in small, rotten pieces.

At the end of each long rest, an infected creature must make a DC 15 Constitution saving throw. On a failed save the creature’s hit point maximum is reduced by 1d10. Once the creature’s hit point maximum is half normal, the creature’s speed is halved. Once the creature’s hit point maximum is a quarter of what it would be without the disease, the creature suffers disadvantage on all attack rolls and saving throws. Once the creature’s hit point maximum is reduced to 0, the creature dies. On a successful save, the creature’s hit point maximum increases by 1. If the creature’s hit point maximum returns to normal, the disease is cured.

Supernatural Diseases

Demonic Plague

Disease, Supernatural

Yellow-green plague shrubs grow in the Abyss.

The plants are harmless to demons, but when their spores are inhaled by a non- demon, a piece of the Abyss is planted in the victim’s body. Demons have been known to craft spore bombs to spread chaos amongst enemies, even among devils.

Creatures who breathe in the spores must succeed on a DC 15 Constitution saving throw or contract demonic plague. Within 1d4 hours of contracting the disease an infected creature grows physically stronger, but begins to lose its mind. The creature’s Strength score is raised to 19 unless it already has a higher score and it gains advantage on all Strength checks and saving throws. The creature’s Intelligence score drops 1d6 points. The creature’s Intelligence score cannot fall below 2 as a result of this disease.

At the end of each long rest, an infected creature must make a DC 15 Constitution saving throw.

On a failed save, the creature’s Intelligence score is decreased by 1d6 points. If the creature’s Intelligence score falls to 2, it desires only to kill and eat creatures of its type and only a greater restoration spell cast by a celestial or fiend can cure the creature. If the creature is a PC the GM takes control of the character until it is cured. On a successful save, the creature regains 1 point of Intelligence. If the creature’s Intelligence score returns to normal the disease is cured.

Ooze Decay

Disease, Supernatural

Humanoids and beasts contract ooze decay by drinking water which an ochre jelly has touched within the past 24 hours. The disease slowly turns its victims more ooze-like until they make complete transformations into ochre jellies.

Any humanoid or beast who drinks tainted water must succeed on a DC 13 Constitution saving throw or contract ooze decay. In 1d4 days the first symptoms begin to appear. An infected creature feels lethargic and hungry. Its skin takes on a pale yellow hue which darkens as the disease progresses.

The creature’s base walking speed is reduced by 5 feet and it has disadvantage on all Dexterity checks and saving throws.

At the end of each long rest, an infected creature must make a DC 13 Constitution saving throw. On a failed save, the creature’s 5 feet. When the creature’s walking speed becomes 10 feet, it transforms into an ochre jelly and if the creature is a PC, the GM takes control of the character. A transformed creature can only be returned to humanoid form by a wish spell. On a successful save, the creature regains 5 feet of its base walking speed. When the creature’s base speed returns to normal, the disease is cured.

Aberrant Touch

Disease, Supernatural

Aberrant touch is a terrifying disease of the mind which drives creatures mad. Aberrations can carry and transmit this disease, but it has no ill effects on their minds. This disease is contracted by communicating telepathically with an infected creature.

A creature who exposes its mind through telepathic communication with another creature must succeed on a DC 15 Intelligence saving throw or contract aberrant touch. In 1d4 hours, the first symptoms begin to appear. An infected creature can only speak and understand Deep Speech, bleeds from its ears, and is covered in sores that ooze lime green pus. The creature also gains a random form of long-term madness.

At the end of each long rest, an infected creature must make a DC 15 Intelligence saving throw. On a failure the creature gains a random form of long-term madness. After three failures, the creature gains a random form of indefinite madness which can only be cured by eating the brain of an intelligent aberration. The disease is cured after three successes.

Other Diseases

In worlds where many diseases can be cured with a single spell or temple visit, more tenacious and pernicious illnesses are bound to fill that gap. Each of the following diseases has one or more levels of infection. Infection levels can be lost through ongoing treatment or the use of magic: a lesser restoration spell reduces a disease’s severity by 1 infection level, a use of a paladin’s lay on hands reduces a disease’s severity by 1 infection level, and greater restoration decreases a reduces severity by 3 infection levels. None of these methods can fully cure these diseases, but when used before a test to increase an infection level they grant a creature advantage.

Faesic Pox

A strange illness from various fey planes, the faesic pox is not particularly virulent but can cause intense distress for the infected. Still, allowing the plant growths that it causes to spread far enough might as well lead to death.

When a non-plant creature consumes food or drink infected with faesic pox (often from the fey realms), it must make a DC 13 Wisdom saving throw or become infected.

Symptoms manifest 1d6 days after being infected and depend on the infection’s level (see Table: Faesic Pox). Intelligence loss from this disease cannot be recovered until an infected creature is cured (a cured creature regains 1d4 Intelligence at the end of each long rest).

This disease can be reversed up until a creature reaches infection level 4. After a creature has stayed at infection level 1 for two weeks or has taken at least 30 fire damage that remains unhealed until finishing a long rest, it is cured of the disease.

Table: Faesic Pox

d6	Effect
1	Initial	The infected creature has an onset of sneezing, runny nose, and watering eyes as though experiencing an allergic reaction. The infected creature has disadvantage on Dexterity (Stealth) rolls. At the end of each long rest, the infected creature makes a DC 18 Constitution saving throw or its infection level increases by 1.
2	Moderate	Previous symptoms end. All manner of flowers grow from the infected creature’s body and it gains resistance to poison. At the end of each long rest, the infected creature makes a DC 16 Constitution saving throw or its infection level increases by 1.
3	Serious	All of the infected creature’s hair, feathers, and fur are replaced with plant life. The infected creature gains immunity to poison damage and cannot be poisoned, but gains vulnerability to fire damage and necrotic damage. At the end of each long rest, the infected creature makes a DC 14 Constitution saving throw or its infection level increases by 1.
4	Critical	Parts of the infected creature’s body gradually become plant matter. At the end of each long rest, the infected creature makes a DC 12 Constitution saving throw or its Intelligence is reduced by 1d6. If this loss reduces the infected creature’s Intelligence to 4 or less, the infected creature transforms into a shambling mound, and it can no longer be cured.

The Fluxx

The fluxx originated in an undetermined outer plane and was brought to the realms material.

Once this sickness has taken hold crystalline growths spread across an infected creature until it is entirely covered. Some even speculate that those who are thought to have died from the illness are still alive, paralyzed and only able to watch the surrounding world.

When a creature is damaged by a creature that carries the disease, it must make a DC 14 Constitution saving throw or become infected.

Alternatively, a creature that eats meat from a creature that carries the disease must succeed on a DC 17 Constitution saving throw or become infected.

Symptoms manifest 1d4 days after becoming infected on the Material Plane or when an infected creature enters the Material Plane, and depend on the infection’s level (see Table: The Fluxx). Dexterity loss from this disease is cumulative and cannot be recovered until a cured creature’s affected limb is restored (a cured creature regains 1d4 Dexterity at the end of each long rest).

There is no way to reverse the effects of the fluxx on a creature after it reaches infection level 2 and any affected limbs must be amputated before this disease can be cured. After a creature has stayed at infection level 1 for a week, it is cured of the fluxx.

Table: The Fluxx

d6	Effect
1	Dormant	No visible effects. At the end of each long rest, the infected creature makes a DC 13 Constitution saving throw or its infection level increases by 1.
2	Initial	The site of the infection (or roll 1d4 to randomly determine which limb) sprouts crystalline structures. The infected creature’s Dexterity is reduced by 2. At the end of each long rest, the infected creature makes a DC 14 Constitution saving throw or its infection level increases by 1.
3	Moderate	The entire limb sprouts crystalline structures that increase the infected creature’s unarmed strike damage to 1d6. The infected creature’s Dexterity is reduced by 2. At the end of each long rest, the infected creature makes a DC 15 Constitution saving throw or its infection level increases by 1.
4	Serious	Crystalline growths spread across the infected creature’s body, increasing its Armor Class by 1. The infected creature’s Dexterity is reduced by 1d4. At the end of each long rest, the infected creature makes a DC 16 Constitution saving throw or its infection level increases by 1.
5	Critical	The infected creature becomes covered by crystalline growths and its unarmed strike damage increases to 1d8. The infected creature’s Dexterity is reduced by 4. At the end of each long rest, the infected creature makes a DC 17 Constitution saving throw or its Dexterity is reduced by 1d4. The infected creature dies if this reduces its Dexterity to 0 as it completely transforms into crystal.

Mycological Wildfire

Spoken of in hushed tones among those who know of it, survivors of this disease claim that they are able to hear and talk to fungi through dreams, as whispers, or in normal conversations. Certain cults are known to cultivate mycological wildfire in careful efforts as the infection tends to make those it infects stronger even as it takes them over.

Sentient Sickness. The most disturbing aspect of mycological wildfire is how it forces victims to act toward strange goals and undertake nonsensical tasks. Many of the diseased descend far below the surface—never to be seen again.

When a creature is exposed to mycological wildfire spores, either through inhalation or consumption, it must make a Constitution saving throw (DC 10 + 1 per previous exposure in the last day) or become infected. Undead can be carriers of mycological wildfire and cause infection with their natural weapons, but are immune to its effects. The ability scores increased by this disease are chosen by the GM, and creatures immune to the charmed condition can still be compelled by mycological wildfire.

After a creature has stayed at infection level 1 for two weeks it is cured of the disease.

Table: Mycological Wildfire

d6	Effect
1	Initial	No apparent signs. At the end of each long rest, the infected creature makes a DC 15 Constitution saving throw or its infection level increases by 1.
2	Dormant	The infected creature starts to lose its sense of smell but there are no other apparent signs. At the end of each short rest, the infected creature makes a DC 15 Constitution saving throw or its infection level increases by 1.
3	Tactile	The infected creature becomes slightly clumsy. When it rolls a natural 1 on a Strength or Dexterity check, it stumbles and falls prone. At the end of each long rest, the infected creature makes a DC 15 Constitution saving throw or its infection level increases by 1.
4	Serious	The infected creature sprouts fungal growths along its body in places that can be hidden beneath clothing, two of its ability scores increase by 1, and whenever it sleeps there’s a 50% chance that it dreams of mushrooms. In addition, whenever the infected creature takes 15 or more bludgeoning, piercing, or slashing damage it releases a cloud of infectious spores in a 5-foot radius. The infected creature is immune to its own spores. At the end of each long rest, the infected creature makes a DC 15 Constitution saving throw or its infection level increases by 1.
5	Loud	The infected creature’s fungal growths spread but can be hidden by a robe (though the hood must stay up to prevent others from seeing the glassy eyes or growths creeping up its neck), two of its ability scores increase by 1, and whenever it takes 5 or more damage it releases a cloud of infectious spores in a 10-foot radius. The infected creature is immune to its own spores. In addition, once per day the disease can force the infected creature to make a DC 15 Wisdom saving throw. On a failure, the disease takes over the infected creature for 1d6+5 rounds. This functions as the dominate monster spell, except the infected creature repeats the saving throw at the end of each of its turns, ending the effect on a success. When the disease takes control for 1 minute or longer, it can do so again within the next 24 hours. At the end of each long rest, the infected creature makes a DC 13 Constitution saving throw or its infection level increases by 1.
6	Critical	The infected creature becomes covered in fungal growths that hijack its body, and it is unable to retain its own mind for any significant amount of time. At the end of each long rest, the infected creature makes a DC 16 Wisdom saving throw or the disease takes over its body until it finishes a long rest.

Wyrm Pox

Believed to originally be a parasite on various draconic species, wyrm pox is a plague feared for both what it does to those it afflicts and what comes afterward. Small wyrmlings are born within the flesh of the infected, slowly eating and growing until they create boils on their host’s body that then burst, causing the wyrmlings to move on to the next phase of their life cycle.

When a creature breathes in a wyrmling egg (each is about the size of a speck of dust), it must make a DC 11 Constitution saving throw or become infected. Celestials, constructs, elementals, fiends, plants, and undead are immune to this disease.

This disease can be reversed up until a creature reaches infection level 4. After a creature has taken 35 poison damage within 24 hours, when it finishes a long rest it can make a DC 14 Constitution saving throw to reduce its infection level 1, curing itself if it is at infection level 1.

Table: Wyrm Pox

d6	Effect
1	Initial	There are a number of sand-sized eggs in the infected creature’s solid waste and after 1 week its infection level increases by 1.
2	Hatching	The sand-sized eggs still in the infected creature’s body hatch and the wyrmlings begin to feed. The infected creature must consume twice as much food as normal and after 1 week its infection level increases by 1.
3	Pupation	Painful and translucent boils spread across the infected creature’s body, minuscule worm-like shapes writhing inside. Whenever the infected creature regains hit points there is a 50% chance that it regains half as many hit points as normal, and when it takes 10 or more piercing or slashing damage one of the boils is popped, forcing the infected creature to make a DC 15 Constitution saving throw. On a failure, it is poisoned for 1 hour. After a number of boils equal to the creature’s Hit Dice have been popped, its infection level is decreased by 1. Otherwise after 1 week its infection level increases by 1.
4	Emergence	The boils across the infected creature’s body become fist-sized with wriggling creatures as big as a finger occasionally swimming up to peer out at the wider world. Whenever the infected creature takes damage, it must make a DC 15 Constitution saving throw or 1d6 pox wyrmlings emerge from boils in its body. The Tiny creatures attack the nearest target in a flurry of activity before retreating when damaged. After 15 or more pox wyrmlings have emerged from the infected creature, it is cured of this disease.

Necrotizing Plague

A disease that rarely causes outbreaks without some other force tipping the scales. This plague is relatively slow moving, and it can last indefinitely in those who have been subjected to it.

If a creature has been bit by another creature with the necrotizing plague, they must make a dc 18 Constitution saving throw or be infected. constructs are immune to necrotizing plague.

Any damage that is done by Necrotizing Plague is permanent, but all other effects are contingent upon the creature’s infection level. Necrotizing Plague can be managed by keeping the Infection level down, but it can only be cured by the revivify spell, which can cure it from any level.

Table: Necrotizing Plague

d6	Effect
1	Initial	There is some redness around the bite that caused the infection, general drowsiness, and possibly aches and pains. Each day after the third day in the Initial Infection state, make a DC 12 Constitution saving throw. On a failure gain an Infection level.
2	Moderate	The sufferer’s flesh begins to turn necrotic and dead across their body, skin begins to slough off, revealing putrid musculature underneath. Despite this, the subject is able to continue to operate largely as normal. Each time the sufferer falls below half their maximum hit points, they must make a DC 14 Constitution saving throw. On a failure, they gain an infection level. The sufferer gains: Resistance to necrotic and poison damage Vulnerability to fire and radiant damage +1 AC (natural armor; necrotic tissues) –2 Intelligence (this loss cannot be recovered with revivify)
3	Critical	The sufferer is more dead than alive at this point. Most of their flesh is dead, their skin has all fallen off, their internal organs barely function. Few can meet their gaze at this point as their eyes are a terrifying piercing bloodshot-gaze. The sufferer: Can no longer consume potions, food, drink, etc Can no longer be healed by spells Creature now counts as undead Gains resistance to slashing and piercing damage Gains immunity to necrotic and poison damage Gains weakness to fire and radiant damage –2 Charisma, –2 Intelligence (this loss cannot be recovered with revivify)

Planar Diseases

GMs know that hitting characters hard can make players jump, but to truly get them quaking try infecting them with something! Fantasy heroes are well?equipped to deal with damage dealt by monsters, fireballs, or falling rocks. Recovering hit points is common and straightforward in most games. More importantly, getting hit isn’t usually dangerous in and of itself—only reaching 0 hit points has a real and visceral impact at the table.

Diseases tend to be unpleasant surprises and present a different kind of challenge, sometimes changing adventurers before a malady has run its course. This article takes that concept a step further with diseases from beyond the world of mortals.

Most have debilitating effects that might sometimes have potential use, but more importantly they shake things around and make the party reconsider the dangers they might face in the future.

Note that just like planar travel itself, these diseases are more suited for higher?level PCs.

While some can have effects that are relevant during combat most are designed with a wider scope in mind, to be used as fun story elements or as a reminder that any dealing with the greater multiverse is dangerous and strange. Also remember that these ailments are not the result of bacteria or virus infection—but then again, who’s to say the germ theory of disease is true in all settings?

Adverse Ascension

Being exposed to too much unfiltered godly glory is deadly to mortals, the simple matter of their flesh and their paltry souls too small to contain such radiance. The most common way to contract adverse ascension is by use of the commune spell, becoming afflicted once every time the caster does not receive an answer. A creature that takes radiant damage equal to triple its total Hit Dice from a celestial source can also cause affliction, but only if its alignment or beliefs are the same as those of the creature inflicting damage. For example, a lawful good paladin of 7th level who takes 21 or more damage from a planetar’s flame strike may become infected with adverse ascension.

A creature overexposed to the divine must make a DC 15 Wisdom saving throw or become infected with adverse ascension. In the first phase, the infected creature’s dreams and daydreams start featuring more of the deity’s aspects and iconography.

After 1d2+1 days of the disease’s first stage, the infected creature must make a DC 12 Charisma saving throw or proceed to the second stage of infection, its alignment shifting one step toward the deity whose power it is infused with (or the god worshiped by the creature that caused the infection). On a success, the creature recovers fully.

At the end of each long rest, an infected creature must make a Charisma saving throw against a DC determined by infection stage (first stage DC 12, second stage DC 13, third stage DC 14). The saving throw is made with disadvantage if within the last 24 hours the infected creature witnessed divine spellcasting by any follower of the same deity as the one it is being drawn to.

On a success while suffering from the second or third stage of infection, the infected creature regresses to the previous stage of infection. On a failure while suffering from the second stage of infection, the infected creature gains the ideal “All must know how great my deity is.” This can manifest in many ways, such as muttered whispered scriptures, or as proudly trying to convert everyone around, depending on the person.

The infected creature begins to show a miraculous understanding of the Outer Planes that gives it advantage on Intelligence (Religion) checks. An infected creature that fails a second saving throw progresses to the third stage of adverse ascension.

On a failure while suffering from the third stage of infection, the infected creature can cast shield of faith once between rests. For the spell’s duration, the infected creature begins to gently fade into the Astral Plane as it is drawn to the divine. At the start of each of its turns, the infected creature makes death saving throws as if dying. The character still acts on its turn as normal, but after three failures, the infected creature dematerializes into the heavens, never to be seen again. Other creatures can use the Help action to grant the infected creature advantage on these saves by speaking encouraging words to it.

After a priest of the same or a similar faith has spent 7 days in one?on?one theology seminars with the infected creature, it makes a DC 12 Charisma saving throw, completely recovering from the disease on a success.

Fractured Rift Disorder

Every being is tied to its native plane, both in terms of the realm’s physical laws and the dimension’s place in the multiverse. On rare occasions that connection can weaken, perhaps even be severed. Frequent travel beyond the Inner and Outer Planes dilutes a soul’s tether to its original plane of existence. Spells such as plane shift and well?made portals are generally safe, allowing for a smooth transition between dimensions, but journeying by other means can have ill effects.

Whenever a creature travels between planes using a naturally occurring portal or dangerous magical item (like a well of many worlds), it must make a DC 15 Constitution saving throw. On a failure, it is infected with fractured rift disorder.

Whenever the infected creature gains a level of exhaustion, its connection to the Material Plane is tested. The character makes a DC 12 Constitution saving throw or is teleported 1d20 feet away in a random horizontal direction as its connection to the here and now shifts slightly.

All of this disease’s effects manifest only while the infected creature is on the Material Plane.

Unless treated (see below) the rift continues to fracture and the infection worsens. At the end of every week during which creature with a basic or mild infection does more than rest, it must make a Constitution saving throw. On a failure, the disease worsens. Consult the Fractured Rift Disorder table below. On a success, its infection reduces by one stage (from mild to basic, or basic to recovered).

Restoration and similar magic have no effect on fractured rift disorder since the problem can’t be fixed with positive energy. Instead, the infected creature needs to strengthen its connection to the world. A druid or similarly nature?oriented person can diagnose the disease with a DC 18 Intelligence (Nature) check and prescribe a long?term treatment, usually requiring a month of peaceful meditation in an ancient grove or cave at the end of which the infected creature recovers.

There are legends about living with fractured rift disorder as well, the most popular claiming that an old dwarven hero afflicted with it crafted a pair of magical iron boots to keep himself grounded.

Fey Longings

The Feywild is a wondrous realm, so enchanting that some start to long for it without ever having been there. After any personal, intimate interaction with a fey, a creature must make a DC 10 Wisdom saving throw or contract this disease. Fey aware of this danger can take special precautions to prevent it using wards made from special plants and oils and though most know this, few care. Characters with fey ancestry (such as elves, gnomes, and half-elves) are immune.

It takes 1d4 days for the symptoms of fey longings to take hold. The infected creature begins to see fey wherever they look. At first it’s the giggling sound of pixies just behind the next tree, but after several days it’s not uncommon for the delusions to include being surrounded by thick vines, glistening psychedelic rains, or riding a colorfully feathered frog (while in fact the infected creature might be tangled in ropes, showered in blood or standing on a swift?moving boat). While these vivid hallucinations are complete, they do not directly lead to a character being harmed or put into harm’s way.

When the infected creature makes an opposed Wisdom (Insight) check or a Charisma (Deception, Intimidation, or Persuasion) check, it must make a DC 12 Wisdom saving throw. On a failure, the character is charmed by one random creature it can see. This creature cannot be an ally of the infected creature. If there’s no viable target, the character instead has disadvantage on attack rolls and ability checks as it sees and tries to interact with a world beyond the veil.

The best cure for fey longings is to bring the infected creature to the Feywild to interact with its denizens and environment. At the end of each day spent in the Feywild, an infected creature makes a DC 10 saving throw to recover from the disease.

Otherwise fey longing naturally fades after a month.

Fractured Rift Disorder

Level	Cumulative Effect	Worsens on…
Basic	Make a DC 12 Constitution save after taking a level of exhaustion, or teleport 1d20 feet in a random direction. Failing a DC 15 Constitution saving throw at the end of a week of adventuring.
Mild	Make a DC 12 Constitution save after scoring or taking a critical hit, teleporting 1d20 feet in a random direction on a failure.
Failing	a DC 17 Constitution saving throw at the end of a week of adventuring.
Severe	Become ethereal (as the blink spell) whenever the infected creature rolls a natural 1 on a d20. Make a DC 12 Dexterity save to avoid dropping held items just before the transition. Automatically worsens after several weeks unless spent resting.
Deadly	When the infected creature has been targeted by a magical effect that changes its form or location within the last round and it makes a Strength check, melee attack roll, or attacks with a thrown weapon, it must succeed on a DC 12 Constitution saving throw or be transported to a random plane of existence.

Pastrasite

This chrono-active parasite is native to Limbo, a result of the ever?shifting environment in which even time is malleable. Unfortunately, pastrasites are drawn to the Material Plane where the rigid temporal structure of past, present, and future provides an excellent foundation to cling to, akin to a caterpillar climbing up and down a tree’s bark.

They are usually contracted in places of historical significance where they exist in a dormant state around the time of the event itself, looking into the future in search of visitors who have an especially interesting past—adventurers.

There’s no certainty as to what a pastrasite looks like as they can only be detected by their symptoms.

They never come in contact with the infected creature itself, instead consuming the character’s background, subsiding on the temporal backlash that results when the timeline snaps back.

When a creature enters an area with pastrasites, it must make a DC 15 Charisma saving throw as their psyche instinctively tries to maintain their personal timeline.

On a success, the pastrasite immediately retreats, choosing another creature to infect. If there are none, it can no longer maintain its temporal existence; it disappears and leaves behind a strong sense of imminence within its would?be victims.

For the next several hours, these creatures all have advantage on Intelligence checks made to recall information.

On a failure, the creature is infected with the disease. The pastrasite immediately destroys several years of the infected creature’s past. If it has one, the character loses its background and gains a randomly determined background. This new background is now, and always has been, the infected creature’s past. The character is vaguely aware of what happened with blurred recollection of things being somehow “different” than before becoming infected. Only spells that contact other planes can reveal information from the infected creature’s previous timeline. Most facts change as little as possible to remain consistent with the infected creature’s new past, but some friction remains. Whenever an inconsistency between the old and new timelines is first spoken of in front of the character, it takes 10 (3d6) psychic damage.

The new timeline gradually settles, and the true past can only be restored through powerful magic such as wish or miracle. Once a pastrasite has altered an infected creature’s timeline, although its effects remain the creature recovers from the disease.

Spells like remove disease or features like a paladin’s lay on hands have no effect on pastrasites.

Spectral Thought-Worms

Spectral thought-worms are tiny parasitic creatures native to the Astral Plane. Their preferred habitat is a conscious mind, where they subside on thoughts and ideals. When a creature interacts with the Astral Plane (via the astral projection spell or magic item mishaps) without the protection of a mind blank spell, or when it suffers prolonged exposure to the less stable areas of the Astral Plane’s wild energies.

Spectral thought?worms can also be carried along a detect thoughts spell, a telepathic connections, and similar effects. A creature exposed to a spectral thought?worm or an infected creature’s mind must make a DC 15 Charisma saving throw or contract the disease.

In 1d4 days the spectral thought?worm’s symptoms manifest in an infected creature. The parasite infests the character’s mind and eats the infected creature’s identity, creating a mental space into which it will lay its eggs. An infected creature’s background characteristics start changing. Roll 1d4 to determine what changes (personality trait, ideal, bond, or flaw) then re?roll the chosen characteristic.

This is the infected creature’s new belief structure, which the character might not notice on its own.

An infected creature that does not have these characteristics has its memories altered instead (as the modify memory spell).

When an infected creature finishes a long rest, it makes a DC 15 Charisma saving throw. On a success, the character’s mind fights against the spectral thought?worm; in the resulting struggle, one of its characteristics changes as above. On a failure, the worm clears enough space to lay eggs that hatch in 1d4 days. These start eating the infected creature’s personality, reducing its Charisma score by 1 each day until the infected creature’s Charisma score reaches 0; the infected creature dies, and the spectral thought?worm escapes to the Astral Plane through the tiny planar opening created by the departing soul.

Spectral thought?worms are susceptible to psychic damage (thus their penchant to hide within minds as a shield against astral energies).

When an infected creature is targeted by lesser restoration or takes psychic damage equal to or more than its Charisma score, the parasite goes dormant for a week. A dormant spectral thoughtworm is destroyed when the infected creature takes psychic damage equal to or more than its Charisma score. Upon destruction, a spectral thought?worm dissolves into stray thoughts that are expelled throughout the next day as semi-insightful sayings that float through the character’s mind.

Umamish are sentient parasites that siphon off nutrients while slowly integrating their fungal roots into a creature’s nervous system until the infestation takes full control of the host, compelling it to seek out dark damp places and lure or capture others for infection. A local legendary swamp monster is suffering from the late stages of umamish infection, and the normally gentle giant has begun snatching local fisherfolk to deposit into her muddy cavern home to be further vessels for the insidious fungus.

Umamish Infection

Umamish are unique among fungi as they are the only parasitic fungus known to have gained sentience. These parasites extract their host’s nutrients while invigorating the victim to keep it alive long enough to spread further spores. When a beast or humanoid creature is exposed to umamish spores, it must make a DC 15 Constitution saving throw or become infected.

It takes 1d4 days for the infection’s first symptoms to manifest in an infected creature. The umamish then grow slowly and their rate of growth varies greatly depending on their host.

Whenever the infected creature advances in a class level, their umamish infection progresses to the next stage (if running this adventure as a short self-contained quest, progress the infected PC immediately to stage 4 infection when they wake the following day.) For NPCs or creatures without class levels, umamish infection progresses to the next stage automatically every 1d4 weeks. If the infected creature spends the majority of its time in a damp and dark environment such as a cave, swamp, or dungeon, its infection progresses to the next stage every 1d2 weeks.

• First Stage. First stage symptoms include warty growths and a persistent rash that covers most of the back and shoulders. The infected creature regains only half the normal number of hit points when spending Hit Dice during short rests as the fungal infection siphons off its vitality. The umamish also act as a blood filter for their host, giving the infected creature immunity to poison damage and all other nonmagical diseases.
• Second Stage. At the second stage of infection the umamish sprout as full mushroom caps with eyes and mouths, gaining the ability to speak and understand any language their host knows. The umamish lie and plead with their host to keep them “happy” about their presence, presenting themselves as “symbiotic.” The umamish make Charisma (Persuasion) and Charisma (Deception) checks with a +8 bonus. As the mushrooms intertwine with a substantial amount of muscle tissue, the infected creature gains a +2 bonus to both its Strength and Constitution ability scores.
• Third Stage. At the third stage of the infection, the umamish fully integrate into their host’s nervous system. The infected creature gains a +2 bonus to its primary spellcasting ability score (or Dexterity if the infected creature does not have the Pact Magic or Spellcasting features). The umamish also become constantly aware of the infected creature’s surface thoughts as per the spell detect thoughts.
• Fourth Stage. At the fourth and final stage of infection, the umamish attempt to control the mind of the infected creature and spread their spores. The infected creature becomes charmed by the umamish as per the spell geas, and it is compelled to infect other creatures with umamish spores and to take infected creatures to damp dark places. Whenever the infected creature hits another creature with a melee attack, that attack deals an additional 3 (1d6) poison damage and the creature must make a DC 15 Constitution saving throw or become infected with umamish. In addition, when the infected creature dies, its corpse explodes with a burst of spores. Each creature within 25 feet of it must make a DC 15 Constitution saving throw, becoming infected with umamish on a failed save.

For every size category larger than Medium the infected creature is, the radius of this trait doubles.

Curing Umamish Infection

An umamish infection is extremely difficult to cure and normal medical and magical means such as the lesser restoration and greater restoration spells are ineffective, as is a paladin’s Lay on Hands.

Umamish are still acting as a blood filter for their host, however, and they can be overloaded by particularly strong toxins. The infected creature is immune to poison damage, but when this immunity would prevent the infected creature from taking 20 or more poison damage from a single attack, the umamish infestation withers away and the creature fully recovers from the disease.