Pox Upon You!

Copyright Clint Fell © 2016

Edited by Bruce Meyer for The Guild Companion

"...the spread of the disease steadily ratchets up the conflict."

Fantasy literature is full of diseases and plagues, and justly so for disease was one of the major threats to life for pre-industrial humans. Fantasy stories often feature gods of disease and great plagues killing droves of innocents; there is no reason this same subject could not work in a role-playing adventure as well. Diseases can act as “MacGuffins”, minor goals or threats to the player characters, or even the main “antagonists” in an adventure. I have written a few ideas for using diseases in your game, as well as game mechanics for some actual and newly imagined diseases below.

A “MacGuffin” is a storytelling tool that acts as a motivation or goal, often without much explanation or actual direct involvement in the story. This is perhaps the easiest way to use a disease in an adventure because there are so many ways a GM could employ it as a motivating force. A plague could be running wild through the kingdom, or perhaps only the child of someone who selflessly helped the PCs is sick. A GM could even inflict a disease on the players and let them rush off to find the cure before it ravages their bodies, minds, or souls. The disease must be appropriate to properly motivate the players but the exact mechanics of the disease are less important. The reason the mechanics are a secondary issue in this case is because the disease is largely only a motivator - it is the results of the disease that matters here. The mechanics of the disease could come into play - especially if the player characters have contracted it - but many of the details may be glossed over.

The most common application of diseases in role-playing games is as a minor threat or goal to an adventure. In this application the disease is a tool being directly used against the PCs. “Watch out for the were-rats, their bites carry lycanthropy” is a prime example of this. The were-rats in this example would be one threat or minor goal for the party to defeat, but anyone bitten may need to find a way to cure the disease before its effects begin to cause them problems. Curing the diseased would be a minor threat or goal for the party (or individual) even after the initial transmission. With this application the exact mechanics of the disease become very important - how is it spread, how easy is it to contract, how is it cured, and what its effects are. Magic or Herbcraft with an appropriately achievable difficulty would be the most common solutions in HARP fantasy, however I’ve occasionally known some players to simply let their character’s impressive constitution pull them through as well. In this application the disease should be fairly curable, or survivable otherwise it should be classified as a major threat or goal.

Disease can likewise be used as the primary antagonist in an adventure. The disease need not even infect the player characters for this application. Classic zombie plague stories are a prime example of this. The protagonists are not (usually) infected but those around them (and whom they may care for) could be. In this case the individual afflicted is not that great of a threat, but the spread of the disease steadily ratchets up the conflict. Finding a way to cure or escape the infection becomes the main goal. This is very similar to using the disease as a MacGuffin, only the disease plays a much more active role in the story. The mechanics of the disease matters more in this case than a disease as a MacGuffin because of the more active role the disease has in the adventure. Characters infected may need to make many more resistance checks, as the disease itself becomes the primary threat to the characters.

A GM should take care with how and when to introduce diseases into a game. Too many plagues and wasting illnesses can make the players wonder what the disease du jour is. Additionally many historical diseases weren’t that fun or interesting - just a slow unpleasant wasting for weeks which isn’t really much fun to play either. The occasional “evil priest of Noxious the Putrid spreading disease” on the other hand can make for a great adventure seed.

Mechanics of Disease:

Base Harp Fantasy does not include special rules for diseases, however Harp Sci-Fi does. The following diseases all use the Harp Sci-Fi disease rules. For those without Harp Sci-Fi these rules function almost identically to the poison rules in Harp Fantasy with the “PB” value replaced by the “AB” value.

Campaign-wide scale mechanics for disease are best resolved with a disease’s basic reproduction number (a number that represents the average number of people who will be infected by a carrier during the diseases contagious period) and its incubation time. A spreadsheet is useful for planning out the spread of a disease in a campaign world, and I would personally recommend using one rather than using complicated equations to do the same.

The basic reproduction number is abbreviated as R0 in this article. As a disease spreads in a closed community the actual rate of contagion typically decreases, and effective methods of combating the spread also reduce the rate of spread. Accurate equations for calculating the spread are simply more complicated than most stories need. A basic simplification I use is to keep the reproduction rate at R0 until 30% of the population have been exposed, then half the R0 for the remainder of the epidemic. For slow spreading diseases like the bubonic plague this will effectively cause the epidemic to kill itself off, but for fast spreading diseases such as smallpox or measles they will still quickly overtake the entire population.

To determine the number of new cases of an epidemic multiply the current number of infected by the modified R0. Repeat this for every incubation period (another simplification). The total number of infected can be tracked by summing this information. The death toll of an epidemic can be tracked by multiplying the number of infected during each incubation period by the mortality rate. A summation of these death can also be kept if it is of value to the game.

Examples of Diseases:

Natural Diseases

Below is a list of historic diseases their common names and their mechanics. Be aware that in medieval times illnesses were usually classified and named for their symptoms not their actual causes; so “the plague” could have been the flea-borne bubonic plague, measles, or maybe a case of smallpox.

Dysentery:

Also known as “bloody flux”

Spread by microorganisms in food or water contaminated with infected feces. Medieval hygiene and sewage problems made this a chronic problem wherever large groups of people gathered (especially armies and cities). R0 varies with the local sanitation, typically low but much higher in medieval cities and army encampments, mortality rate of 1%

  • CRR (150) No effect
  • CRR (130) Cramps and mild diarrhea (-5 to AG stat bonus) for 1d10 hours after 2d10 hours.
  • CRR (110) Severe Cramps and diarrhea (-10 to AG stat bonus and -5 to CN stat bonus) for 1 to 5 (1d10/2) days after 1 to 5 days.
  • CRR (90) Severe Cramps, diarrhea, bloody stool, dehydration (-15 to AG stat bonus, -10 to CN stat bonus, suffers d10 hits of blood and water loss per day). Make a RR(100) check daily after 1 to 5 day incubation to see if disease stops.
  • Failure. Severe Cramps, diarrhea, bloody stool, dehydration (-20 to AG stat bonus, -15 to CN stat bonus, suffers 2d10 hits of blood and water loss per day). Make a RR(120) check daily after 1 to 5 day incubation to see if disease stops.

Ergotism:

Also known as “holy fire” or “devil's fire”

Spread by a fungal contamination of rye and other grains. R0 is 0 in humans, but spread quickly in rye. Mortality rate was typically 20% but could be as high as 70%.

  • CRR (130) No effect
  • CRR (110) Subject has mild hallucinations and an intense burning sensation. Subject’s skin blackens and blisters. -5 to RE stat bonus.
  • CRR (90) Subject has vertigo, hallucinations and an intense burning sensation. Subject’s skin blackens and blisters. -10 to RE stat bonus and -5 to IN stat bonus.
  • CRR (70) Subject has vertigo, hallucinations and an intense burning sensation. Subject’s skin blackens and blisters then begins to rot. -15 to RE stat bonus and - 10 to IN stat bonus. Subject loses 1d10 hits per day to necrosis until healed or a daily RR(100) is made.
  • Failure. Subject has vertigo, hallucinations and an intense burning sensation. Subject’s skin blackens and blisters then begins to rot. -20 to RE stat bonus and - 15 to IN stat bonus. Subject loses 2d10 hits per day to necrosis until healed or death.

Influenza:

Also known as “Grippe” or “Sweating Sickness”

A viral upper respiratory infection spread by inhalation or contact with contaminated surfaces AB (30). R0 of 2, mortality rate of about 0.2%

Subject suffers from fever, headache, muscle aches, weakness, and nausea after 1-2 days. Subject suffers from sore throat, cough, runny nose after 1-5 (1d10/2) days. After 5 days of symptoms subject may make a daily Stamina RR (100) to recover. Note that critical failures on this recovery roll may indicate the subject has progressed to pneumonia or a more severe infection.

Leprosy:

A bacterial infection spread by inhalation or contact RR (50). R0 of 1.3, mortality rate is near 0% but complications due to the disease may kill eventually.

Subject suffers a cumulative -5 PR (max -20) stat bonus every 1d10 months as voice and facial features degenerate, and scaly spots erupt on the skin. RR(75) per year to avoid paralysis of the extremities. RR(50) per year to avoid blindness.

Note: in the interest of story and game excitement the mechanics for leprosy presented here are actually much more contagious and fast acting than often experienced in the real world. Current theory holds that only about 5% of the population are genetically susceptible. A GM in a fantasy setting may wish to dictate that some races are completely immune or more susceptible to leprosy.

Malaria:

Also known as “the ague”

A bloodborne disease typically spread by mosquitoes AB (50). Historically this was thought to be caused by “bad air”. R0 in humans is 0, but via mosquito spread can vary from 1 to 6 depending on local conditions (typically around 1.2). Mortality rate is about 1%.

Subject experiences shakes, chills then high fever and severe headache (-25 to all maneuver rolls). After 1d10 hours subject experiences extreme sweating (taking 2d10 hits of damage from fluid loss) then headache and fever stop. Roll percentile when contracted on 01-50 symptoms recur every two days, on a 51-00 symptoms recur every three days. Subject may make a RR(100) after every fever cycle to recover from the disease.

Measles:

Also known as a “Pox” or occasionally a “Plague”

An extremely contagious respiratory viral infection spread through contact or the air. Usually somewhat minor in the historic “Old World” but devastating to populations it was introduced to. R0 is 16(very high!), mortality rate is 2% (5% for un-resistant populations, and as high as 10% for malnourished populations).

  • CRR (150) No Effect
  • CRR (120) Cold like symptoms after 1d10+5 days. 3 days after symptoms start mild spots appear on mouth and a mild itchy rash on the next day. Subject suffers -5 AG stat bonus while symptoms are present. RR (100) daily after symptoms develop to recover.
  • CRR (100) Cold like symptoms after 1d10+5 days. 3 days after symptoms start mild spots appear on mouth and a itchy rash on the next day. Subject suffers -10 AG stat bonus while symptoms are present. RR (100) daily after symptoms develop to recover.
  • CRR (70) Severe Cold like symptoms after 1d10+5 days. 3 days after symptoms start spots appear on mouth and a severe rash on the next day. Subject suffers -15 AG stat bonus while symptoms are present. RR (100) daily after rash develops to recover.
  • CRR (30) Severe Cold like symptoms after 1d10+5 days. 3 days after symptoms start spots appear on mouth and a severe rash on the next day. Subject suffers -20 AG stat bonus while symptoms are present and a -10 CO stat bonus that must heal separately. Complications with the disease cause blindness. RR (100) daily after rash develops to stop the progression of the disease.
  • Failure Severe Cold like symptoms after 1d10+5 days. 3 days after symptoms start spots appear on mouth and a severe rash on the next day. Subject suffers -20 AG stat bonus while symptoms are present and a -15 CO stat bonus that must heal separately. Complications with the disease cause death 1d10 days after the rash develops.

Note: Subject who have already contracted this disease will be immune to it, while those from a society unexposed to it should receive a -25 penalty to the CRR roll.

Plague:

A bacterial infection spread by fleas or occasionally respiration. R0 for human spread is low, around 1.3, but flea spread can be as high as 6. Mortality rates for the plague are about 60%.

  • CRR (180): No Effect
  • CRR (130): After 2-6 (1d10/2 +1) days any infected bites begin to rot and swelling of lymph nodes cause large painful buboes. Subject also suffers from headache, fever and delirium causing a -10 stat bonus penalty to both RE and IN. Subject may make a daily RR(120) to recover from the plague.
  • CRR (80): After 2-6 (1d10/2 +1) days any infected bites begin to rot and swelling of lymph nodes cause large painful buboes. Subject also suffers from headache, fever and delirium causing a -20 stat bonus penalty to both RE and IN. Subject loses 2d10 hits per day and may make a daily RR(120) to recover from the plague.
  • CRR (50): After 2-6 (1d10/2 +1) days any infected bites begin to rot and swelling of lymph nodes cause large painful buboes. Subject also suffers from headache, fever and delirium causing a -20 stat bonus penalty to both RE and IN. Subject loses 4d10 hits per day and after 1-5 (1d10/2) days begins coughing and sneezing. Subject becomes very contagious (-25 to CRR roll to resist Pneumonic Plague). Pneumonic Plague persists until death.
  • Failure Plague goes septicemic, subject suffers from headache, fever and delirium causing a -20 stat bonus penalty to both RE and IN then dies within 3d10 hours..

Smallpox:

Also known as “red plague”

A highly contagious airborne virus spread by respiration. R0 is high at 6, and mortality rate is 30%.

  • CRR (150): No Effect
  • CRR (100): After 12 day’s subject suffers fever, chills, headache and backache causing a -5 AG stat bonus penalty. After 4 more days an itchy red rash of pus filled blister forms on the face, arms, legs, and sometimes chest. During this phase of the disease the Subject’s AG stat bonus penalty rises to -10. After 9 additional days the blisters break and dry up alleviating penalties.
  • CRR (75): After 12 day’s subject suffers fever, chills, headache and backache causing a -5 AG stat bonus penalty. After 4 more days an itchy red rash of pus filled blister forms on the face, arms, legs, and sometimes chest. During this phase of the disease the Subject’s AG stat bonus penalty rises to -10. After 9 additional days the blisters break and dry up alleviating penalties but leaves the subject with visible scarring (permanent -5 modifier to maneuvers involving appearance).
  • CRR (40): After 4 day’s subject suffers fever, chills, headache and backache causing a -10 AG stat bonus penalty and the subject skin blackens taking 1d10 hits of blood loss per day. After 4 more days an itchy red rash of pus filled blister forms on the face, arms, legs, and sometimes chest but the bleeding continues After 9 additional days the bleeding stops, the blisters also break and dry up alleviating penalties but leaves the subject with visible scarring (permanent -5 modifier to maneuvers involving appearance).
  • Failure: After 4 days subject suffers fever, chills, headache and backache causing a -10 AG stat bonus penalty and the subject skin blackens taking 3d10 hits of blood loss per day. After 4 more days an itchy red rash of pus filled blister forms on the face, arms, legs, and sometimes chest but the bleeding continues After 9 additional days the bleeding stops, the blisters also break and dry up alleviating penalties but leaves the subject with visible scarring (permanent -5 modifier to maneuvers involving appearance).

Typhoid fever:

Also known as “Slow Fever”

Bacterial infection spread by fecal contamination of food and/or water AB (60). R0 depends on local sanitation, but is 0 for human to human spread. Mortality rate is 15%.

Subject afflicted with this disease experiences a steadily increasing temperature for the first seven day. After the fourth day the subject takes a -5 penalty to QU and AG stat bonuses. During the second week of infection the subject suffers a high fever with red patches on the abdomen. During this week the subject also suffers from either protracted diarrhea or constipation and the penalty to QU and AG stat bonuses increases to -10. During the third week the subject begins taking 1d10 hits damage per day to intestinal hemorrhaging, and dehydration. The -10 penalty to QU and AG stat bonuses persists through the third week as well. During the fourth week survivors stop bleeding and their fever steadily drops until full recovery. During the final week of infection the subject takes a -5 penalty to QU and AG stat bonuses until fully recovered.

Gangrene:

A bacterial infection occurring in wounds AB (30). R0 for humans is near 0, mortality rate is around 25%.

The infected wound festers and begins to rot. Subject takes 2d10 hits of damage per day to tissue loss. Infected limbs will be completely lost in 1-5 (1d10/2) days. The infection persists until the infection is removed or the subject makes a daily RR (120) check. The infection can be removed by modern medical treatment (antibiotics/antiseptics and surgery), magical treatment, historical medical treatment (maggots and antiseptic poultices - a Very Hard Healing maneuver), or amputation (a Hard Healing maneuver which also runs the risk of gangrene if not done in a sterile manner).

Magical and Fantastic Diseases

In a world of magic with a variety of natural and unnatural creatures, fantastic and magical diseases are very likely to be present. Here are some new fantasy and magical diseases and their mechanics:

Goblin Mange:

A bacterial infection spread by bed-bugs, mites and fleas. Goblin Mange is sometimes encountered in seedy inns and has an AB of 30. R0 is between humanoids is 0, but rates of spread depend on local conditions. Mortality rate is 0 but death from related complications and infections could occur.

Effects: Symptoms appear after 6-10 days causing hair loss and a rash in patches all over the body. The symptoms cause a -10 penalty to all maneuvers involving appearance until cured. Additionally a fever, runny nose and itching cause a -10 penalty to all SD or AG maneuvers for 1d10 days or until cured. Goblinoids and Gnomes are particularly sensitive to this disease, receiving a -25 penalty to the Stamina RR check to avoid this disease and require a RR(150) check daily after the 1d10 days to recover. Goblin Mange can be treated with a very hard Healing check, but if a hyacinth and brimstone poultice is available it is only a Hard check.

Mage Shakes:

A supernatural infection of incorporeal Aetherborn parasites that’s common in magical haunted ruins and ley lines. AB(60) resisted by a Will RR when exposed to botched spells by infected casters or in infested areas. Spells that magically link someone to an infected spellcaster can also spreads the Mage Shakes. R0 is typically low but depends on the spellcaster. Mortality rate is 0% but death from related complications could occur.

Effects: 1d10 hours after infection the subject suffers from a clouding of the mind and intense involuntary shaking causing a -20 to all RE, IN, and AG maneuvers for 2d10 hours and the parasites consume 2d10 recoverable PP. Thereafter the subject must make a will RR (100) daily or the symptoms reappear. Mage Shakes may be cured magically with either a Cure Disease or Remove Curse but only if the subject has spent or been drained of all PP. The subject may also make a Will RR (150) to expel the parasites once a day if their PP are at 0.

Medusa Rot:

Spread by contact with infected creatures that have petrification abilities. RR100 + 10 per 5 levels of the infected carrier. Cannot be spread by non-petrifiers. R0 in most humanoids is 0, but high amongst petrifiers is at 6. Mortality rates are 0 but death from complications of the disease could occur.

Effect: Medusa Rot causes an unsightly dust-like appearance to the afflicted’s skin. Symptoms appear in 1d10-1 hours after exposure. Another 1d10 hours after the symptoms appear Medusa Rot causes a reduction of natural toughness (-10 to toughness/natural defenses) as it embrittles the subject’s skin.

Diseases in Published Harp materials

  • HARP fantasy:
    • pg 162 “Wasting Disease” in Giant Rat entry.
    • pg 164 “Lycanthropy” in Werewolf entry.
    • pg 165 “Degenerative Disease” in Zombie entry.
  • HARP Sci-Fi:
    • pg 136 Cetan Pox, Collintay’s Syndrome, Crimson Death, Eridani Nerves, Pavonian Fever, Pilnag’s Condition, Spacer’s Flu. With a name change most of these (especially Crimson Plague) from Harp Sci-Fi would make a wonderful magical disease.
  • HARP MaFG:
    • pg 44 Lycanthropy
    • pg 78 Ghoul’s Curse
    • pg 91 Contagion (Zombie)
  • HARP CoM
    • pg 86 and 87 The Chills, Grey Vision, Smelling Loss, Hearing Loss, Allergy, Tongue Rot, The Pox, Wasting Disease, The Shakes, Fever, Leprosy, Hemophilia, Pneumonia, The Black Death. All in the Disease Spell.CoM Leprosy and The Black Death are more cinematic (and simpler) versions of the same diseases I presented in this article.