Simple Disease Rules

Or, Schrödinger's Illness.




When a disease is contracted, make a save. If failed, the disease will strike at dawn the following day. To survive a disease, make a save every day for three consecutive days. -2 to save if not resting. When diseased, you are unable to heal HP by resting.   

Potency

A disease's strength is defined as its Potency, which determines the maximum amount of symptoms it will inflict on the PC, all rolled randomly from the list below.
Potency could be determined by rolling a d6.


Transmission Types

For game purposes, treat all diseases as contagious. They spread through these means:

1-2.Physical transmission.
Occurs by physical contact.

3-4. Pestilential transmission.
Occurs by being close to the victim for an extended time.

5-6. Airborne transmission.
Occurs by passing close to the victim, or by touching objects handled by them.


When a PC has successfully survived a disease, note down its transmission type, symptoms, and give it a suitable name. The next time a PC could get infected by a disease there is a 50 % chance of selecting one of these defined diseases, or roll up a new one.


Symptoms
A symptom marked with * is cumulative, and is reapplied every time the PC fails a save vs disease.

1. Coughing. When the victim attempt to sneak or perform a strenous action, make a Constitution check or cough violently.
2. Agony*. +1 to all damage taken.
3. Fever. Victim’s body temperature fluctuates wildly – from hot to cold – and muscles ache. All rolls are penalized by 2.
4. Fatigue. The victim can only stand up one Turn at a time, then have to rest for one Turn.
5. Excretions. Each combat round there is a 1 in 6 chance that a standard action is lost after defecating/vomiting, etc.
6. Exhaustion. After every round of combat beyond the first, take a -1 cumulative penalty. Spending one round resting will reset this penalty.
7. Bleeding*. Take 1 damage.
8. Blindness.
9. Deafness. +1 to being surprised.
10. Sneezing. Can't smell anything, can't surprise others.
11. Muteness.
12. Itching Rashes. Each round there is a 1 in 6 chance that the victim must stop and scratch themselves for 3 rounds or take -2 to attacks and AC if they don't.
13. Nausea. Victim can't eat, and must make a Constitution check every time he performs a stressful physical action to avoid being physically sick. Vomiting lasts for 1d3 rounds during which he cannot act.
14. Paralyzation. Victim is unable to move.
15. Cramps*. One of the victim's limbs is unusable.
16. Arrhythmia*. +1d6 damage on critical hits.
17. Confusion. As the spell confusion in combat, and once per day the victim is subject to a hallucination.
18. Dizziness. 1 in 6 each combat round that the victim must make a Dexterity check or fall prone.
19. Mania. Victim is driven to follow some compulsion; such as avoiding water, paranoia, self mutilation, and so forth
20. Weakened Immune System. -2 to further saves to resist disease.

Reroll any duplicates.