Plague of Undeath

The plague was devised by the fallen shaman Ner'zhul after he was transformed into the Lich King by Kil'jaeden. From his icy seat atop the Frozen Throne in Northrend, Ner'zhul perfected the sickness as an unholy vanguard for the Burning Legion's invasion. Testing his power on isolated human villages across Northrend, he discovered that he could snuff out life and psychically command the corpses that arose shortly after. Ner'zhul's telepathic summon reached across the Great Sea to the Kirin Tor mage Kel'Thuzad, who abandoned Dalaran to serve the entity. Kel'Thuzad organized the secretive Cult of the Damned, whose mortal infiltrators laid the groundwork to poison Lordaeron from within.

The blight extends far beyond humanity. While non-human fauna generally suffer sickening fevers or rot rather than rising as undead thralls, the land itself bears the brunt of demonic and necromantic decay. Across the Plaguelands, massive plague cauldrons pump alchemical and magical vapors directly into the atmosphere, corrupting the surrounding land, where carrion grubs and colossal spore-choked mushrooms thrive. The Argent Dawn actively battles this airborne corruption by sabotaging these cauldrons, reversing their catalytic mixtures to burn the Scourge rather than feed it. Meanwhile, in the Undercity, the Royal Apothecary Society experiments tirelessly to refine a New Plague designed to slay both living foes and the undead.