One aspect of scenario or campaign design, that is often overlooked is Diseases. This list of 24 diseases, range from the near instantly fatal Ebola; to sometimes amusing STD's.
One nice thing to see, is the addition of real world diseases; into a fantasy setting like Pathfinder. However this has to be tempered with a note of caution, given the severity of the diseases. All the diseases enclosed in this publication, cause debilitating consequences of contracting them. For instance Fungal Riot, found dank dungeons and lightless carverns, can cause 1d10 temporary Constitution damage; half of which becomes permanent if untreated.
A handy guide to adding some realism to your game, but use with caution.
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