Pockets of diseased air drift through the Abyss. These vapors are often invisible, and those that can be seen appear innocuous. Light within an area of infectious pallor looks slightly different from that in surrounding areas. Also, creatures within this terrain appear sickly and wan, and any wounds they take seem to ooze with infection.
Effect: Each area of infectious pallor carries a specific disease. Any creature that starts and ends its turn in a square of infectious pallor (even if they are different squares in the same area) is exposed to that disease. A common plague of the Abyss is demon pox.
Usage: This terrain works well with undead and elemental creatures, both of which are commonly immune to disease and have no fear of being within the area. The disease you pick determines how scary the pallor is. Try positioning this terrain around areas that you want to be challenging to reach, or in places you want characters to pass through quickly.
Published in The Plane Below, page(s) 16.