Thanks; that's actually pretty helpful. I can post what I currently have for a challenge the group will be facing. The format is somewhat rough for the time being; it's something I quickly sketched out in my notes for a disease created by the cult. It is named after the cult member who cooked it up. I'd appreciate some feedback. The progression of the disease is very rapid, but that's somewhat intentional; it's meant to be a biological weapon produce by a cult dedicated to a demon lord of filth and disease.
Stench of Fecus
Easily visible Symptoms - The whites of an infected individual's eyes will begin to turn to a brownish color. The further along the disease progresses, the more the change occurs. Those in the final stages have eyes (the entire eye) which appear to be a solid brown color. They also move in a manner which is sluggish; shambling in an almost zombie-like manner.
Blood Agent - The disease can be contracted either by contact with an infected's blood or by having the disease (via a weapon coated with it) come into contact with your blood. If you've only touched the blood of an infected, the roll to resist is HT-2. If the disease comes into contact with your blood or you have a wound exposed to it, the roll to resist is HT-4. If you've ingested the disease or diseased blood, you are treated as having failed your first roll (see below) against the disease, and the second roll will occur in 3 hours rather than 6.
Secret Lore - ingesting Cardamom boiled into water slows the progress of the disease and doubles the time between each roll. Doing this also allows someone who has ingested diseased blood to make a HT roll to resist rather than suffering an automatic failure on the first roll.
Progression of Disease
1) After 10 seconds; HT-4 roll.
Success at this point resists the disease; you are not infected.
Failure causes you to lose 2 FP which cannot be recovered until cured.
2) After 6 hours; HT-4 roll.
Success - disease does not progress... yet
Failure - Lose 2 Basic Speed which cannot be recovered until cured.
3) 12 Hours after progressing to step 2 (above); HT-4 roll
Success - disease does not progress... yet
Failure - Stench: You begin to smell like a cross between rotting meat and sun baked sewage. The game effects of this are that you acquire a reaction penalty equal to your margin of failure. Other creatures get a bonus to perception checks against you equal to your reaction penalty.
4) 24 hours after progressing to step 3 (above); HT-4 roll
Success - as above
Failure - You acquire the Decreased Time Rate disadvantage. Also, your stench increases; add your margin of failure from this roll to the reaction penalty associated with step 3.
5) One week after progessing to step 4 (above); HT-4 roll
Success - as above
Failure - Lose 1d6 fatigue
6) Each addition week after progressing to step 5 (above); HT-4 roll
Success - no FP loss this week
Failure - Lose 1d6+(number of weeks) FP.