These diseases are appropriate threats for characters from levels 1 to 4, and for higher-level characters that lack easy access to curative magic.
Blue Welts
This disease only affects humanoids. It can be found lurking in most major cities and urban centers, as well as in sewers and swamps. Symptoms manifest after 1d4 days and include aches, chills, and loss of balance. The infected creature gains one level of exhaustion that can’t be removed until the disease is cured. It also suffers dis-advantage on Dexterity saving throws for the duration.
After 1d4 additional days of the disease, painful blue welts begin appearing across the body of the infected creature. It gains another level of exhaustion that can’t be removed until the disease is cured, and it suffers dis-advantage on saving throws to maintain concentration or to resist other diseases for the duration.
A humanoid that spends at least 1 hour within 15 feet of an infected creature before finishing a long rest must succeed on a DC 11 Constitution saving throw or be infected with the disease. A humanoid that drinks water tainted by blue welts must also make the saving throw.
An infected creature must make a DC 11 Constitution saving throw every 24 hours after symptoms appear. Once a creature has succeeded on at least three of these saves during an infection, the disease ends.
Blue welts can be cured using a rare herb called red clover, which grows on some mountains. Given an hour, a character who has proficiency with an Herbalism kit can turn a handful of red clovers into one dose of antidote. If drank before a long rest, one dose prevents the disease from worsening for 48 hours. After three doses, the antidote cures the disease entirely.
Bruise Fungus
This disease can affect beasts, humanoids, and plants. It can be found lurking in murky swamps, dark forests, and dank caverns, spreading via spores in the air and water. Living things without blood that carry the disease suffer no symptoms from it, but still produce and spread the spores. Symptoms manifest 1d6 + 4 hours after infection. While infected by the disease, a creature suffers the following ailments:
Bruising. Whenever the creature takes bludgeoning damage, its hit point maximum is reduced by an amount equal to the bludgeoning damage taken. The reduction lasts until the creature finishes a long rest.
Sensitivity. The creature has disadvantage on saving throws to maintain concentration or resist magical pain.
Stricken. Whenever the creature expends hit dice to regain hit points, it rolls each hit die twice and must use the lower result. In addition, it regains half as many hit dice as normal whenever it finishes a long rest.
Weakness. The creature gains one level of exhaustion that can’t be removed until the disease is cured. While it has this exhaustion, its carrying capacity is halved.
Any humanoid within 10 feet of an infected creature when it takes bludgeoning damage must succeed on a DC 11 Constitution saving throw or become infected. Once a creature succeeds on this save, it is immune to infection from that particular creature for 24 hours. A creature that finishes a long rest in an environment that is tainted by bruise fungus also makes the saving throw.
An infected creature must make a DC 11 Constitution saving throw every 24 hours after symptoms appear. Once a creature has succeeded on at least three of these saves during an infection, the disease ends.
Cinder Rash
This disease affects humanoids and giants. It is often carried by fire giants, who suffer no symptoms from it, but regularly spread it to other communities in the wake of their raids by their armies. It can also be contracted by touching fresh volcanic ash falling from an eruption. Symptoms manifest 1d4 hours after infection and include extreme itchiness, sweating, and irritability. 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 great stress — including entering combat, taking damage, experiencing fear, or having a nightmare — forces the creature to make a DC 12 Constitution saving throw. On a failed save, the creature ignites. Until a creature takes an action to douse the fire, the target takes 3 (1d6) fire damage at the start of each of its turns.
Any humanoid or giant within 10 feet of an infected creature when it ignites or that attempts to douse the fire must succeed on a DC 12 Constitution saving throw or also become infected with the disease. A fire giant that carries the disease won't ignite, but instead causes this effect at random times as if it had ignited.
At the end of each long rest, an infected creature can make a DC 12 Constitution saving throw. On a successful save, the DC for this save and for the save to avoid igniting drops by 1d6. When the saving throw DC drops to 0, the creature recovers from the disease.
A remedy for this disease can be brewed using arctic herbs and a small amount of frost giant blood or white dragon blood. This takes one hour and requires proficiency with alchemist's supplies or brewer's supplies. The remedy must be applied to the skin, and it cures the disease after 1d4 hours.
Fell Feral Fever
This disease, carried and spread by feral hags, can affect beasts, fey, humanoids, and monstrosities. Hags are naturally immune, except that feral hags carry the disease without exhibiting any symptoms. Symptoms manifest 1d4 days after infection. While infected by the disease, a creature suffers the following ailments:
Hydrophobia. The creature feels compelled to avoid liquid water. It will only drink when necessary.
Insomnia. When the creature finishes a long rest, it must succeed on a DC 10 Constitution saving throw to gain any benefit from the rest.
Mania. When the creature finishes a short rest, it must succeed on a DC 10 Wisdom saving throw to gain any benefit from the rest. If the creature is a beast, it is also more aggressive than normal.
Sunlight Sensitivity. While in sunlight, the creature has disadvantage on attack rolls, as well as on Wisdom (Perception) checks that rely on sight.
After 1d4 additional days of the disease, a creature also suffers from intermittent madness:
Madness. The creature must make a DC 12 Charisma saving throw every 24 hours. On a failed saving throw, it must roll on the Long-Term Madness table from the Dungeon Master's Guide and suffer the effects for the rolled duration. While it suffers from madness, it also foams at the mouth, and it can be affected by spells and magic as if it were a beast with no more than 4 Intelligence.
Fell Feral Fever has a special symbiosis with the curse of lycanthropy. A creature afflicted by the disease has disadvantage on saving throws against the curse of lycanthropy, and lycanthropes have disadvantage on saving throws against the disease. When a creature is afflicted with lycanthropy by a lycanthrope that is suffering from the disease, that creature is afflicted by the disease automatically.
An afflicted creature can transmit the disease by biting. When it deals damage to a creature using a bite attack, the target must succeed on a DC 12 Constitution saving throw or be infected by the disease.
An afflicted creature must make a DC 12 Constitution saving throw every 24 hours after symptoms appear. Once a creature has succeeded on at least three of these saves during an infection, the disease ends.
Frost Torpor
This disease affects humanoids and beasts. It originates with creatures that stay out in icy winds for too long. Symptoms manifest after 2d4 hours and include chills, fatigue, shakes, aches, sneezing, and congestion. The infected creature gains two levels of exhaustion that can’t be removed until the disease is cured. Its speed is also reduced by 10 feet for the duration. If the creature has resistance or immunity to cold damage, it suffers no symptoms, but it can still pass the disease on to others.
Any humanoid or beast that spends at least 6 hours within 60 feet of an infected creature without finishing a long rest must succeed on a DC 12 Constitution saving throw or become infected with the disease. A creature that gains at least two levels of exhaustion from time spent in extreme cold must also make this saving throw.
An infected creature must make a DC 12 Constitution saving throw every 24 hours after symptoms appear, with disadvantage if it spent the majority of the last 24 hours in an environment of extreme cold. Once the creature has succeeded on at least three of these saves during an infection, the disease ends.
A remedy for this disease can be brewed as a special tea using leaves from the ashwood tree, which grows on some volcanic slopes. This takes one hour and requires proficiency with brewer's supplies. Drinking the tea cures the disease after 1 hour.
Rancid Mucus
This disease affects humanoids. It is often found in the air of foul swamps and jungles. Symptoms manifest 1d4 hours after infection and include sneezing, coughing, sweating, and pungent body odor. The infected creature gains one level of exhaustion that can’t be removed until the disease is cured, and it also suffers these ailments:
Mucus Fits. Whenever the infected creature tries to exert great effort, such as lifting a heavy weight, casting a spell of 1st-level or higher, or critically hitting with an attack, it must succeed on a DC 11 Constitution saving throw or its efforts fail; its spell fails or its attack misses. In addition, if it fails the saving throw, the creature is poisoned and its speed is halved for 1 minute as it sneezes or coughs uncontrollably. The creature can repeat the saving throw at the end of each of its turns, ending that mucus fit on a success.
Rancid Stench. When another creature within 90 feet of the infected creature finishes a short or long rest, that creature must succeed on a DC 11 Constitution saving throw to gain any benefit from the rest. This counts as a poison effect.
Any humanoid that spends at least 6 hours within 60 feet of an infected creature without finishing a long rest must succeed on a DC 11 Constitution saving throw or be infected with the disease. A humanoid that starts its turn within 10 feet of an infected creature in the throes of mucus fits must also make the saving throw. Once a creature succeeds on this save, it is immune to the mucus fits of that infected creature for 24 hours.
An afflicted creature must make a DC 11 Constitution saving throw every 24 hours after symptoms appear. On a failed saving throw, the creature's hit point maximum is reduced by 3 (1d6). It dies if this effect reduces its hit point maximum to 0. Once it succeeds on at least three of these saves during an infection, the disease ends, and the creature's hit point maximum is restored.
Rancid mucus can be cured using a special remedy brewed from rare salts obtained from certain salt flats. This takes one hour and requires proficiency with alchelmist's supplies or brewer's supplies. A creature that bathes in the remedy for 1 hour is cured of the disease.
The Shaving
This infamous disease affects humanoids and beasts that can grow hair. It is caused by tiny mites that are too small to see, which infest the skin and hair follicles of the victim. Symptoms manifest 1d4 hours after initial infection and include itchiness, rashes, and hair loss. The itchiness worsens greatly in the presence of water; while the infected creature is immersed in water, it has disadvantage on ability checks and attack rolls.
After 1d4 days of infection, the infected creature has shed all the hair and fur on their body; the hair will not regrow until the disease is cured. A creature missing hair in this way has disadvantage on Charisma (Performance) checks for audiences that care about such appearances. It also regains only half as many hit dice when it finishes a long rest.
Any garments made of fur or fibers, including most clothing, will become infested with the disease if worn by an infected creature for more than 1 minute. Once removed, the garments remain infested for 1d4 days. Any creature that wears infested garments for more than 1 minute must succeed on a DC 11 Constitution saving throw or become infected with the disease.
Infected creatures almost never recover from the disease naturally. The disease can be cured using a remedial wig fashioned entirely from a young sheep's first coat of wool and doused in a new mother goat's first milk. Creating this remedy takes four hours and requires proficiency with weaver's tools. The first 1d4 infected creatures to finish a long rest while wearing the remedial wig are cured of the disease.
Vile Consumption
This disease can only affect humanoids, and spreads through the dark miasma that blows out from certain graveyards and battlefields. A creature that finishes seven long rests in a row within 10 miles of such a place must succeed on a DC 13 Constitution saving throw or else be infected with the disease. On a success, the creature is immune to the disease for 1d4 + 1 years.
The immediate symptoms are pallor and persistent coughing. After 3d6 + 10 weeks of infection, the disease and its symptoms increase in severity, and the infected creature suffers the following additional ailments:
Convalescence. Each time that the infected creature wakes from sleep, it must make a DC 13 Constitution saving throw, with advantage on the saving throw. On a failed saving throw, its exhaustion level increases to five. It removes up to four levels of exhaustion gained in this way the next time it finishes a long rest.
Wasting. When this ailment begins and every 7 days after that, the infected creature must succeed on a DC 13 Constitution saving throw or take 5 (1d10) necrotic damage. The creature's hit point maximum is reduced by the amount of damage taken, and it is restored only when the disease ends. The creature dies if this effect reduces its maximum hit points to 0.
Weakness. The infected creature's carrying capacity is halved, and it has disadvantage on Strength checks and Constitution checks.
An infected creature makes a DC 13 Constitution saving throw each time it gains a level, as well as every year after infection. On a successful saving throw, the disease ends and the creature is immune to the disease for 1d4 + 1 years.
These diseases are appropriate threats for characters from levels 5 to 10, and for higher-level characters that lack easy access to curative magic.
Blood Worms
This disease, which is actually a parasitic infection, can affect beasts, dragons, humanoids, and undead, but only those with blood. These worms are native to the wet places of the Underdark, but they are often spread by their unsuspecting hosts up to the surface. A creature that consumes meat tainted by blood worms must succeed on a DC 14 Constitution saving throw or be infected with the disease.
Symptoms manifest after 2d6 + 7 days of infection. They include itchiness in the limbs, fatigue, nausea, and swelling in the legs and feet. The infected creature gains one level of exhaustion that can’t be removed until the disease is cured, and its traveling speed is reduced by half while it has this exhaustion. After an additional 2d6 + 7 days of infection, the exhaustion increases by two additional levels.
When an infected creature with symptoms takes slashing or piercing damage or damage from a Blood spell, worms spill from the creature's wounds. Each other creature within 5 feet of the infected creature must succeed on a DC 14 Constitution saving throw or be infected with the disease. If the disease is cured by magic, worms spill from the creature's body with even greater abundance, and each creature within 10 feet of the infected creature must make the saving throw with disadvantage. A creature that is normally immune to disease can still be infected, but it has advantage on the saving throw to resist infection.
Infected creatures almost never recover from the disease naturally. The disease can be cured by chewing the roots of a rare herb known as Fairblood Leaf, which only grows in rare forest locations, upon ground where blood has never been spilled.
Green Leprosy
Despite its fearsome reputation, this magical disease (a special form of leprosy) only affects armadillos and a small portion of humanoids. The first time a humanoid would be infected, it rolls a d6. On a result of 3 or higher, the humanoid is immune to the disease and always will be. Symptoms can take a long time to appear: 1d6 days after the victim gains a level, or after 1d6 years, whichever comes first.
The disease comes with the following symptoms.
Diseased Flesh. The infected creature experiences constant rashes and patches of green skin discoloration, where the flesh is numb and weak, reducing its carrying capacity by half and giving it disadvantage on Dexterity (Sleight of Hand) checks. It also suffers from persistent eye problems and runny nose, giving it disadvantage on Wisdom (Perception) checks. Any creature that touches the infected creature must succeed on a DC 14 Constitution saving throw or be infected by the disease.
Foul Health. The infected creature has disadvantage on saving throws against poison or other diseases. When it finishes a long rest, it regains hit points equal to half of its maximum hit points instead of regaining all missing hit points, and it doesn't regain any expended hit dice. Every 1d4 months, the creature must succeed on a DC 14 Constitution saving throw or its maximum hit points are reduced by 2d4, lasting until the disease is cured. The creature dies if its maximum hit points are reduced to 0 by the disease.
Loss of Limbs. The infected creature's body parts are numbed and fragile, ready to be torn or chopped off at the slightest trauma. Whenever the creature is critically hit by a melee attack, if the creature has less than half of its hit points after the attack's damage is dealt, the creature must succeed on a DC 14 Constitution saving throw or else the attack severs one of the creature's fingers, toes, ears, or its nose, chosen randomly. If the creature fails the saving throw by 5 or more, it loses a random limb instead. For the effect of losing a limb, see the new petrify spell. The infected creature must also make this saving throw every 1d4 months.
If the infected creature dies or loses any body parts, each piece of dead flesh sprouts a special plant that grows to full size within 1d4 hours, with the plant's size equal to the size of the body part or corpse. The plant is known as Leperwort, and it looks like a cross between a mushroom, a flower, and a fern. Any creature that starts its turn within 15 feet of the plant or enters the area for the first time on a turn must succeed on a DC 14 Constitution saving throw or be infected with the disease.
Infected creatures almost never recover from the disease naturally. However, an infected creature that is experiencing symptoms makes a DC 14 Constitution saving throw every 1d4 years. On a successful saving throw, the disease goes into remission, and the creature stops experiencing the disease's symptoms for 1d6 years. A special elixir can be brewed using oil harvested from leperwort that forces the disease into remission. Creating this elixir takes 3 days and requires proficiency with alchemist's supplies or an herbalism kit.
Magic that cures diseases only allows the infected creature to make a DC 14 Constitution saving throw, sending the disease into remission for 1d10 months on a success. The disease can be removed only by heal or another disease-curing spell of 6th-level or higher.
Phantasthma
This magical disease affects humanoids, fey, and giants. It occurs naturally in some elderly fey, but it can also be caused by repeated inhalation of the residual dust from magical crystals. A creature exposed to the disease must succeed on a DC 15 Constitution saving throw or be infected with the disease. Symptoms manifest after 2d4 weeks and include fatigue, shortness of breath, and extremely vivid dreams. The infected creature has disadvantage on saving throws against exhaustion.
In addition, any event that causes the infected creature great stress — including entering combat, taking damage, experiencing fear, or having a nightmare — forces the creature to make a DC 15 Constitution saving throw. The creature must also make this saving throw if it ends its turn while unable to breathe. On a failed save, the creature becomes struck with a phantasthma attack for 1 minute, during which time it is unable to move or breathe for 1 minute.
In addition, 1d4 + 2 illusions of hostile creatures (chosen by the DM) appear in unoccupied spaces within 30 feet of the infected creature. The illusions seek to terrify and kill the infected creature, acting as if they were created by the phantasmal force spell (DC 15), except other creatures can also perceive them as if they were real. The infected creature repeats the saving throw at the end of each of its turns. On a successful saving throw, or if the infected creature is targeted with an effect that cures diseases, the illusions disappear and the phantasthma attack ends.
Infected creatures almost never recover from the disease naturally. However, an infected creature that is experiencing symptoms makes a DC 15 Constitution saving throw every month. On a successful saving throw, the disease goes into remission, and the creature stops experiencing the disease's symptoms for 1d4 + 1 months. The disease can be removed only by heal or another disease-curing spell of 6th-level or higher.
Rust Pox
This disease affects beasts, fey, and humanoids. It is acquired when a creature takes damage from a rusted metal object that carries the disease. Any creature that is exposed to the disease must succeed on a DC 14 Constitution saving throw or else be infected with the disease. Symptoms manifest 3d6 days after initial infection and include itchiness, sweating, headaches, fevers, and blemishes. The infected creature also gains one level of exhaustion that can’t be removed until the disease is cured, and it suffers the following symptoms:
Lockjaw. The infected creature suffers intense muscle spasms from time to time. These spasms are especially strong in the muscles of the jaw, causing the mouth to clench shut painfully. Any event that causes the infected creature great stress — including entering combat, taking damage, experiencing fear, or having a nightmare — forces the creature to make a DC 14 Constitution saving throw. On a failed saving throw, the creature begins to spasm, becoming restrained and unable to speak for 1 minute as spasms overtake it. It repeats the saving throw at the end of each of its turns, ending the spasming on a success and taking 1d6 + 1 bludgeoning damage on a failure.
Touch of Rust. Any nonmagical metal objects the infected creature is holding or carrying rust over time. For every 10 minutes that an object is carried or held and every time the object is used to make an attack, it rusts. A weapon takes a permanent and cumulative −1 penalty to damage rolls. If its penalty drops to −5, the weapon is destroyed. Metal armor or a metal shield takes a permanent and cumulative −1 penalty to the AC it offers. Armor reduced to an AC of 10 or a shield that drops to a +0 bonus is destroyed. Any other metal object is destroyed after 30 minutes.
Any creature that touches an infected creature or takes damage from an object rusted from this disease must succeed on a DC 14 Constitution saving throw or be infected with the disease. Sometimes, metal objects that have completely rusted but have not encountered the disease are spontaneously tainted by the disease in a process that continues to mystify scholars. A creature that succeeds on the saving throw is immune to being infected by the disease for 24 hours.
At the end of each long rest, an infected creature can make a DC 14 Constitution saving throw. On a successful save, the DC for this save and for the save to avoid muscle spasms drops by 1d6. When the saving throw DC drops to 0, the creature recovers from the disease. A creature that fails three of these saving throws has its Dexterity score permanently reduced by 1d4 + 1, and it dies if its Dexterity score is reduced to 0. This reduction can be removed by the greater restoration spell.
Rust pox can be cured using the liver from a rust monster. Given an hour, a character who has proficiency with alchemist's supplies can combine the liver with 100 gp worth of platinum powder to create one dose of curative elixir. Applied to the skin before a long rest, one dose prevents muscle spasms for 24 hours. After three doses, the elixir cures the disease entirely.
Rust pox can't be instantly cured by lesser magic. It can be removed only by heal or another disease-curing spell of 6th-level or higher. Less-powerful magic, such as the lesser restoration spell, can only reduce the saving throw for muscle spasms and recovery by 1d4.
Shapeshift Shudders
This rare magical disease can only affect humanoids. It usually affects those who finish a long rest in the more magical parts of the Feywild, but it can also result from teleportation mishaps or the flow of wild magic. Any creature that is exposed to the disease must succeed on a DC 15 Constitution saving throw or else be infected with the disease. On a success, the creature is immune to the disease for 2d4 months.
Symptoms manifest 1d4 minutes after infection. They include chills, headaches, and pain along the spine. An infected creature also suffers from involuntary shakes, causing the creature's Dexterity score to be reduced by 5 (minimum score of 1) and imposing disadvantage on Dexterity checks and saving throws while it is infected.
In addition, each time the creature falls asleep for any reason, it must succeed on a DC 15 Charisma saving throw or else become disguised following the rules in the disguise self spell, except the DM chooses the appearance of the illusion, and the effect lasts until the creature fails the Charisma saving throw again or the disease is cured. The DM can choose to use the table from the reincarnate spell to help randomly determine the appearance, if they desire.
The infected creature makes a DC 15 Constitution saving throw every 48 hours that pass after infection. On a successful save, the DC for this save and for the save to avoid being disguised by the disease drops by 1d6. When the saving throw DC drops to 0, the creature recovers from the disease. A creature that fails three of these saving throws has its Dexterity score permanently reduced by 1d4, even after it recovers from the disease. A creature with a Dexterity score of 0 suffers the effects of being restrained, even if it can't be restrained.
The disease can be cured using a lock of hair from a hag, such as a green hag or death hag. Given an hour within the Feywild, a character who has proficiency with alchemist's supplies can turn the hag hair into an elixir. When consumed, the elixir cures the disease entirely.
Shapeshift shudders can't be instantly cured by lesser magic. It can be removed only by heal or another disease-curing spell of 6th-level or higher. Less-powerful magic, such as the lesser restoration spell, can only reduce the saving throw for both saves by 1d4.
Zombie Plague
This magical disease can affect humanoids and undead, but only humanoids suffer symptoms from it. It can be found in the blighted and defiled parts of the Shadowfell and the Lower Planes among fouled waters and smog. Many claim that it first originated from the domain of the Demon Lord Orcus, where it is omnipresent.
Initial symptoms manifest after 1d4 + 1 hours of infection. They include pallor, spasms, and fatigue. The infected creature also gains one level of exhaustion that can’t be removed until the disease is cured. While it has this exhaustion, its speed is also halved.
Symptoms worsen after 2d4 + 3 hours of infection. The infected creature's maximum hit points are reduced by half until it recovers from the disease. In addition, it must succeed on a DC 14 Wisdom saving throw when it starts its turn within 30 feet of a humanoid that has no more than half of its hit points or else it must spend its movement and action on its turn to attack the creature. Every hour, the infected creature must succeed on a DC 14 Constitution saving throw or else it immediately dies and turns into a zombie that carries the disease.
Any humanoid that is hit with a melee attack using a natural weapon, such as a bite or a slam, must make a DC 14 Constitution saving throw if the attacker carries the disease. A creature that consumes food, water, or air tainted by the disease must also make the saving throw, except with disadvantage. On a failed save, the creature is infected by Zombie Plague. On a successful saving throw, the creature is immune to the disease for 1 hour.
Infected creatures almost never recover from the disease naturally. However, holy water can be used as a remedy. It must be ingested, allowing the infected creature to make a DC 14 Constitution saving throw with advantage after 1d4 minutes. It has no effect on a failed save, and it cures the disease on a successful save. Once this remedy has been used, repeated doses have no effect on that creature for the next 12 hours.
These diseases are appropriate threats for characters from levels 11 to 16, and for higher-level characters that lack easy access to curative magic.
Blood Flux Fever
This magical disease can only affect humanoids that have blood. It is transmitted by the wild fiends of the Lower Planes through contact with saliva, blood, or venom, but some very advanced hemomancers have managed to spawn the disease in the Material Plane out of nothing but uninfected humanoid blood.
Symptoms manifest after 1d4 + 2 hours and include extreme fevers, fatigue, and intermittent rashes found distributed across the body. The infected creature has three levels of exhaustion that can’t be removed until the disease is cured. In addition, whenever it finishes a long rest, it must roll on the Blood Magic Ailment table (Impermissicon page 239) and suffer the result of its roll until it finishes its next long rest or the disease is cured.
Any creature that comes into contact with the bodily fluids of an infected creature, such as blood, sweat, or saliva, must make a DC 17 Constitution saving throw. On a failed saving throw, the creature is infected with the disease. On a successful saving throw, the creature is immune to the disease for 24 hours. A creature that consumes these fluids has disadvantage on the saving throw, and its symptoms manifest twice as quickly.
Infected creatures almost never recover from the disease naturally. The disease also can't be cured by lesser magic; heal and other disease-curing spells of 6th-level or higher prevent the creature from suffering symptoms for the next 24 hours. If the creature suffers no symptoms for three days in a row, the disease is cured. Otherwise, the disease can be removed only by mass heal or another disease-curing spell of 9th-level.
Bone Fusion
This magical disease affects humanoids and undead skeletons, although they suffer different symptoms. The disease resides in the bones of corpses. It is often found in old tombs and crypts and commonly afflicts reckless cultists and novice necromancers. Particularly skillful necromancers may attempt to make use of the disease for their own purposes, keeping it carefully cloistered in experimental chambers packed with infected skeletons. The skeletons fuse together into powerful abominations to be thrown against intruders and other foes.
Symptoms manifest in humanoids after 1d4 + 2 weeks of infection and typically include extreme joint pain and stiffness, itchiness, and loss of balance. The creature's speed is reduced by 10 feet, its Dexterity is reduced by 2, and it has disadvantage on attack rolls and on Dexterity checks and saving throws. Every 24 hours after that, the infected creature must succeed on a DC 16 Constitution saving throw or else its Dexterity is further reduced by 2, to a minimum score of 0, until the disease is cured. A creature with a Dexterity score of 0 suffers the effects of being restrained, even if it can't be restrained.
Undead that are infected with the disease suffer a set of alternate symptoms after only 1d4 hours of infection. An infected undead has its speed reduced by 5 feet and suffers disadvantage on Constitution saving throws, but its body fuses with any external bones that it touches, so the undead slowly accumulates bones until it becomes a new undead, such as a skelepede.
Any creature that touches an infected creature or the corpse of an infected creature must succeed on a DC 16 Constitution saving throw or be infected with the disease.
Infected creatures almost never recover from the disease naturally. The disease also can't be cured by lesser magic; heal and other disease-curing spells of 6th-level or higher prevent the creature from suffering symptoms for the next 24 hours. If the creature suffers no symptoms for three days in a row, the disease is cured. Otherwise, the disease can be removed only by mass heal or another disease-curing spell of 9th-level, or through the use of an esoteric remedy. This remedy is brewed from the dusty flesh of a mummy lord, which takes 3 hours and requires proficiency with herbalism kits and alchemist's supplies. The disease is cured 1d4 minutes after drinking the brew.
Rebellious Flesh
This rare magical disease can affect humanoids, beasts, dragons, fey, and giants. It is believed to originate from the Far Realm, and it spreads through contact with the denizens of that strange place.
The disease comes with the following symptoms that manifest after 1d6 + 4 hours.
Bubbling Rashes. The infected creature suffers from rapidly-growing rashes that spread downward from the neck. These rashes cause intense pain and itchiness. As a result, the infected creature suffers disadvantage on saving throws to maintain concentration and on ability checks that require focus or attention over a period of more than one minute. In addition, the creature suffers vulnerability to acid damage because of how easily the afflicted skin sloughs off and melts away.
Rebel Limbs. Whenever the infected creature tries to exert great effort, such as lifting a heavy weight, casting a spell of 1st-level or higher, or critically hitting with an attack, it must succeed on a DC 16 Constitution saving throw or its efforts fail; its spell fails or its attack misses. In addition, if it fails the saving throw, its limbs begin to rebel against it for 1 minute. At the start of each of the creature's turns, it must repeat the saving throw. On a failed saving throw, it rolls 1d6. On a result of 1 or 2, the infected creature can't move or make attacks until the start of its next turn. On a 3 or 4, it is restrained until the start of its next turn. On a 5 or a 6, it must make a melee attack against itself using a weapon it is holding, or an unarmed attack if it isn't holding any weapons. On a successful saving throw, that limb rebellion ends.
Restlessness. Each time that the infected creature finishes a short or long rest, it must succeed on a DC 16 Constitution saving throw to benefit from the rest.
Sleepfighting. When the infected creature is asleep, it continues to act and move as if it were awake, except the creature is under the DM's control and acts as if it were chaotic evil with an Intelligence score of 4. In this state, the creature can't be woken up unless it succeeds on a DC 16 Charisma saving throw.
A creature that is hit by the natural weapons of an infected creature or that consumes food or drink tainted by the disease must succeed on a DC 16 Constitution saving throw or be infected with the disease.
Infected creatures almost never recover from the disease naturally. The disease also can't be cured by lesser magic; heal and other disease-curing spells of 6th-level or higher prevent the creature from suffering symptoms for the next 24 hours. If the creature suffers no symptoms for three days in a row, the disease is cured. Otherwise, the disease can be removed only by mass heal or another disease-curing spell of 9th-level, or through the use of magical crystal healing.
An infected creature that finishes a long rest with at least 3 star sapphires within 5 feet of it doesn't suffer the disease's symptoms for the next 24 hours. However, once a crystal is used for a long rest in this way, it can't be used for this purpose again until the crystal spends an entire night bathed in direct moonlight.
Toxic Ambrosis
This magical disease affects humanoids, monstrosities, beasts, and dragons, but tabaxi suffer no symptoms. It can be found in almost any environment in the Material Plane, but is especially prevalent in the deepest parts of the Underdark and in monster lairs. Physical contact with the excrement of an infected creature is the most common way of acquiring the disease, but the disease can also be contracted by consuming the flesh of an infected creature. Any creature that does either of these actions must succeed on a DC 16 Constitution saving throw or become infected with the disease.
Symptoms manifest 3d4 days after infection. They include chills, fatigue, headaches, and congestion. The infected creature gains one level of exhaustion that can’t be removed until the disease is cured.
In addition, the infected creature's body odor changes to smell strongly of intoxicatingly delicious food, such as juicy meats or decadent pastries. As a result, all wild animals and predatory monsters from within 5 miles are attracted to attempt to eat the infected creature. In combat, those creatures will always attack the infected creature before all other targets, attempting to kill and consume the infected creature as their primary goal.
Finally, the infected creature can't be frightened, and it feels no instinct to defend itself from deadly harm by another creature. Instead, the infected creature feels a strong compulsion to recklessly seek out danger. Each time the infected creature finishes a long rest, it must succeed on a DC 16 Wisdom saving throw or else it is compelled to venture forth on its own to seek danger until it finishes its next long rest. During this time, other creatures have advantage on attacks made against it.
The infected creature makes a DC 16 Constitution saving throw at the end of each long rest. If it succeeds on five of these saving throws in a row without failing any, the disease is cured in that creature.
Toxic ambrosis can't be cured by lesser magic; heal and other disease-curing spells of 6th-level or higher prevent the creature from suffering symptoms for the next 24 hours. If the creature suffers no symptoms for three days in a row, the disease is cured. Otherwise, the disease can be removed only by mass heal or another disease-curing spell of 9th-level.
Warp Warts
This rare magical disease can only affect humanoids that are native to the Material Plane. It's known to afflict creatures that experience mishaps when traveling the planes or teleporting using magic, such as being sent to the wrong place or accidentally releasing monsters. Any creature that is exposed to the disease, including by touching an infected creature, must succeed on a DC 17 Constitution saving throw or become infected with the disease. Symptoms manifest 3d6 weeks after infection and include warts that cause the following ailments:
Extreme Pain. Because of pain, the infected creature suffers disadvantage on saving throws to maintain concentration and on ability checks that require focus or attention over a period of more than one minute.
Planar Warping. Whenever the infected creature finishes a long rest, it must make a DC 17 Charisma saving throw with advantage. On a failed saving throw, the creature is transported to a random location upon a random plane following the rules of the plane shift spell. The DM rolls a d8 and compares the result to the table below to determine the plane.
| d8 | Plane or Realm |
|---|---|
| 1 | The Feywild |
| 2 | The Shadowfell |
| 3 | The Ethereal Plane |
| 4 | An Elemental Plane |
| d8 | Plane or Realm |
|---|---|
| 5 | An Upper Plane |
| 6 | A Lower Plane |
| 7 | A Plane of Chaos |
| 8 | A Plane of Law |
Teleportation. Whenever the infected creature takes damage, it must succeed on a DC 17 Charisma saving throw or be teleported to a random unoccupied space of the DM's choice within 90 feet. On a successful saving throw, the creature doesn't suffer from this symptom until the start of its next turn.
An infected creature can make a DC 17 Constitution saving throw each time it finishes a long rest. Once the creature succeeds on three of these saving throws in a row without failing the saving throw, the disease is sent into remission and the creature doesn't suffer from any symptoms for the next 6d6 weeks.
The disease can also be sent into remission through the use of extreme heat or cold drawn from one of the Elemental Planes, such as a salamander's flame or the chill of an ice elemental. If this elemental heat or chill is applied to the warts while within the Elemental Plane it originated from, the creature suffers no symptoms for the next 24 hours. If this is done for three days in a row, the disease is sent into remission for 6d6 weeks.
Infected creatures almost never recover from warp warts naturally. The disease also can't be cured by lesser magic; heal and other disease-curing spells of 6th-level or higher prevent the creature from suffering symptoms for the next 24 hours. If the creature remains in this state for three days in a row, the disease is cured. Otherwise, the disease can be removed only by mass heal or another disease-curing spell of 9th-level.
These diseases are appropriate threats for characters of level 17 or higher. They are extremely dangerous.
Pale Plague
This legendary magical disease, known for destroying entire kingdoms in a matter of days, affects beasts, dragons, humanoids, and giants. It creeps through the air insidiously and invisibly. According to old legends, the disease originated from the dusty remains left behind by a powerful vampire lord, who invoked the disease as a dying curse upon the world. Some say the disease still lurks in reservoirs hidden within the ancient tombs of the eldest vampire lords, waiting to be unleashed upon the hapless world again.
Upon infection, symptoms manifest after 1d4 hours. The infected creature experiences aches, pallor, and a persistent cough. It also gains 2 levels of exhaustion that can’t be removed until the disease ends. After that point, every 4 hours, the infected creature must succeed on a DC 20 Constitution saving throw or take 28 (8d6) necrotic damage and gain a level of exhaustion. Its hit point maximum is also reduced by an amount equal to the necrotic damage taken until the disease ends. If an infected creature succeeds on three of these saves in a row, the disease ends for that creature.
Any creature that spends at least 1 minute within 60 feet of an infected creature without finishing a long rest must succeed on a DC 20 Constitution saving throw or be infected with the disease. Infected creatures that die begin to disintegrate into pale white ash, which drifts on the wind and spreads the disease. Infected corpses are treated like infected creatures, except they can infect creatures from 300 feet away rather than only 60 feet. Any creature that touches an infected body or infected ash must also make the saving throw. A creature that succeeds on the saving throw is immune to infection by the disease for the next 8 hours.
The Pale Plague is a powerful and eldritch disease. If an infected creature is cured by magic, the magic forces the disease out into the air. One random creature within 120 feet of the cured creature must succeed on a DC 20 Constitution saving throw or be infected by the disease, even if that creature is normally immune to infection.
Stone Scourge
This magical disease affects beasts, dragons, giants, and humanoids. Though many believe the origins of the disease lie with the creatures called medusas, most who acquire it are infected by dao, who can unknowingly carry the disease without suffering any symptoms.
Upon infection, symptoms manifest after 2d6 hours. The infected creature suffers numbness in their limbs along with fatigue, weakness, and extreme drowsiness. It gains 2 levels of exhaustion that can’t be removed until the disease ends. While it has this exhaustion, its carrying capacity is halved and it deals only half damage with weapon attacks that use Strength. In addition, it has disadvantage on saving throws against being put to sleep by magic, it needs twice as much sleep as normal, and it must sleep during its short and long rests, which both take twice as long as normal.
After 2d6 additional hours, the disease reaches its final stage. The infected creature must succeed on a DC 18 Constitution saving throw or become petrified until the disease ends. It must repeat the saving throw every 4 hours unless it is already petrified.
This disease is not suppressed while the infected creature is petrified. Instead, an infected creature that is petrified exudes the disease. Its stone body is splotchy and discolored in overlapping patches. Only melting the statue with acid will prevent it from infecting others.
Any creature that spends at least 1 hour within 120 feet of an infected creature without finishing a long rest must succeed on a DC 18 Constitution saving throw or be infected with the disease. Each minute that is spent near a petrified infected creature counts as one hour. A creature that touches an infected creature must also make the saving throw, with disadvantage if the infected creature is petrified. A creature that succeeds on the saving throw is immune to the disease for 24 hours.
Magic that can cure diseases is only able to reduce the severity of this disease. The heal spell or another disease-curing spell of 6th level or higher reduces the petrification DC for an infected creature by an amount equal to the spell slot level. The DC increases by 1 every hour until it returns to its normal value. If the save DC is reduced to less than 1, the disease is cured. All other magical effects are unable to cure the disease.
A remedy for this disease can be brewed from the bones of a stone giant and the scales of a medusa. This takes five hours and requires proficiency with alchemist's supplies and a successful DC 18 Intelligence check using the tools. On a failed check, the brewer must also make a saving throw against infection by the disease. Applying the remedy as an ointment upon the skin of an infected creature cures the disease after 1d4 hours.
The Unraveling
This horrifying magical disease can affect any type of creature except constructs, even those that are normally immune to disease such as gods, archfiends, and other immortal beings. However, creatures that never leave the Material Plane cannot acquire the disease. It is not contagious, and while the nature of infection is not fully understood by mortal minds, stories tell of it affecting only those who live or travel among the other planes. Some claim that the Unraveling is a mistake in the weaving of creation and life itself, a defect that emerges only in rare cases. Others claim it is a curse laid upon the world by the alien terrors of the Far Realm, or the result of ancient magic gone terribly awry.
The Unraveling reverses the fundamental bonds of Order and Creation that define what a creature is and what it is not, causing what normally keeps it whole to begin tearing it apart instead. Symptoms manifest an unknown time after acquisition of the disease, but begin with aches, confusion, loss of balance, and fatigue. The infected creature gains 2 levels of exhaustion that can’t be removed until the disease is cured. With time, the creature's skin starts to peel back in thin ribbons and strips: the tell-tale sign of the Unraveling.
After 3d6 years of infection, the disease accelerates. The infected creature begins slowly peeling apart, both mentally and physically. Every 24 hours, the infected creature must succeed on a DC 20 Constitution saving throw or take 27 (5d10) force damage, and it must succeed on a DC 20 Wisdom saving throw or gain a new long-term madness and a new indefinite madness, as described in Chapter Eight of the Dungeon Master's Guide. The creature's hit point maximum is reduced by an amount equal to the force damage taken, lasting until the disease is cured, and any indefinite madness caused by the disease can't be ended until the disease is cured.
After 100 years of infection, the infected creature's hit point maximum is reduced by 1d4 for every additional year that passes, lasting until the disease is cured.
If the disease reduces a creature's maximum hit points to 0, the creature instantly dies and cannot be resurrected by any means, including the wish spell.
Infamously, the Unraveling cannot be cured, even by the most powerful magic such as the wish spell. There is no possibility for natural recovery once a creature has acquired the disease, even for the most immortal beings in the multiverse. However, the ancients of the world tell tales of a mythical group of heroes who eons ago found a cure, but only at the end of a legendary adventure and at great personal cost. These stories must be from eras before the gods themselves, yet could they be real?
Umbramania
This infamous magical disease can affect any creature that has a shadow except constructs and undead. The disease originates from the Plane of Negative Energy itself, and can be found lurking in the foul darkness of the Shadowfell and the Lower Planes, where light has not penetrated for centuries or more. A creature that spends more than 10 minutes in darkness that is fouled by umbramania must succeed on a DC 19 Constitution saving throw or be infected with the disease. A creature that succeeds on the save can't be infected for 24 hours.
Initial symptoms manifest after 2d6 × 10 minutes and include shakes, muscle spasms, and mood swings. The infected creature also suffers the following ailments:
Insomnia. When the creature finishes a long rest, it must succeed on a DC 19 Constitution saving throw to gain any benefit from the rest.
Mania. When the creature finishes a short rest, it must succeed on a DC 19 Wisdom saving throw to gain any benefit from the rest.
Paranoia. The creature has disadvantage on saving throws against being frightened, and it must make any opportunity attacks that it can, regardless of the target.
After 1d6 additional hours of infection, the disease worsens and the infected creature's shadow starts to take nefarious control of its body. Any event that causes the creature great stress — including entering combat, taking damage, experiencing fear, or having a nightmare — causes the creature to be affected by the new incite self-harm spell.
After 8 hours of infection, the disease reaches its final stage. The infected creature begins to hear a voice in its mind that no one else can hear, beckoning it to act in treacherous ways and betray its allies. The voice also insists that if the creature does not follow its orders, the voice will kill the creature using its own body. Until the disease is cured, while the infected creature is at 0 hit points, a shadow occupies its space and takes its turn immediately after the infected creature's turn. The shadow is immune to all damage, conditions, and effects, and desires only to kill the infected creature. Once the creature has more than 0 hit points, the shadow disappears.
If the infected creature dies at any stage during the disease, a new shadow rises from its corpse and seeks out a location of persistent darkness in which to take a long rest. If it finishes a long rest in a place of darkness, the shadow dies and the darkness in that location is fouled with umbramania. Light can prevent infection by casting away darkness, but when the light fades, the darkness that returns will be just as diseased.
The disease can be removed only by mass heal or another disease-curing spell of 9th-level. Creatures that are immune to disease are not immune to this disease, but they have advantage on saving throws against it.
