While never named in previous sourcebooks, the Slow Death is the patron of the Plaguebearers, one of the Carrion Tribes of the Demon Wastes. Ashurak revels in the horror of disease. The plagues they spread are agonizing and disfiguring, but never kill quickly; lingering suffering is Ashurak’s hallmark. While their prison is in the Demon Wastes, their influence can be carried by the diseases they create, and Plaguebearers have occasionally started cults in the Five Nations.
While one might expect these cultists to find allies among the Children of Winter, the truth is quite the opposite; the maladies of Ashurak are deeply unnatural, and the druids battle these cults whenever they find them. Ashurak isn’t one of the most powerful or infamous overlords, but they do have representatives among the Lords of Dust; their speaker is Shalashar, a native oinoloth.
Source: Chronicles of Eberron