It flows across time, a disease floating on Quantum Foam.
Sumerians called it the Eater. In Babylon they named it Nergal's Rot. Dead tongues dubbed it the Devouring Plague, the Zero Point Pathogen, the Dark Homunculus, the Blackworm Jism. Information is a super-weird substance, sometimes floating as oil, sometimes vapour, invisible waves, pollution, roiling black storms, a viral rhyme.
It is the harbinger of change - the sizzling, celestial syphilis. The flesh mutates. The mind boils to bilious madness. All lucid thoughts to slay. All sweetlings are fair game to the drip.
—The Buzzing on The Filth, The Secret World
Nurgle's Rot, as I have indicated before, is not a mortal illness. It is entirely supernatural and daemonic in nature, not so much infecting its host as possessing them. Indeed, the fate of those damned and poor unfortunates who contract the disease is not simply to rot away and die, but to be transfigured in body and soul into one of Nurgle's Tallymen - a daemonic footsoldier in the service of the Lord of Decay.
And indeed this is the most horrifying aspect of contracting the Rot: the certainty of one's own damnation, regardless of how much one might wish it otherwise. Short of employing the most powerful magic, there is simply no way to escape it.
Animescence is a rare disease of the Elder Continent. A slow combustion of the soul, gradually baking the vital organs. Poets suffer worse than most; lovers worst of all. The blistered monks who run the hospital will accept any assistance.
I believe I am not understating when I say that the second sin unleashed the bane of all life upon Thedas. The Darkspawn are more virulent than the worst plague, a heartless force of nature that came into our world like an ill wind. We know from accounts of later Blights note that the Darkspawn spread disease and famine wherever they tread. The earth itself is corrupted by their presence, the sky roiling with angry black clouds. I do not exaggerate, my friends, when I say that a mass gathering of Darkspawn is an omen of dread cataclysm.
—"The First Blight," Dragon Age: Inquisition
Lois: Don't you see what's happening?
Peter: Of course I do, Lois. Our fresh-faced little boy is becoming a pock-marked, hideously disfigured man. Sunrise, sunset.
Brian: No, no, no, Peter! The light bulbs last night? My fleas? Chris' pimples? They're just like darkness, gadflies and boils, three of the plagues God visited upon Egypt when the Pharaoh angered Him in the Old Testament.
—Family Guy, "If I'm Dyin', I'm Lyin'"