Morgion

Morgion the Seething is the god of envy and an avid promoter of disease, and decay. Green dragons are his loyal followers due to their common resentful nature. Morgion is a loner, who rarely talks to or acts with the other gods. He prefers to hatch his own plans in a far corner of the Abyss, rather than discuss them. Morgion is perhaps the most reviled of the gods, and his followers must meet in secret, under the orders of the Nightmaster. 
Cultists of Morgion carry pouches with several special powders including sleep and illness ones. They also carry weapons embedded with poison. Since even when reunited they cover their factions with hoods and masks, it is custom for the cultists to mark people, named the mark of Morgion. The mark is seen by other cultists and some priests of other religions, but not by common people. It indicates the cultists that the bearer should not be harmed.
As Hiddukel, Morgion may appear to dying people, especially if it is due illness, and make a pact: heal them in exchange of becoming cultists and spreading his plague. When the cultist is dying, or decides to break the pact, Morgion returns the original illness.