Ner'zhul's Scourge refers to the undead army created by the orc shaman Ner'zhul after he was transformed into the Lich King. This army was formed to spread death and destruction across the world of Azeroth, serving the Lich King's will. The Scourge is known for its ability to raise fallen enemies as undead minions, creating a relentless force that threatens all living beings. The Scourge played a significant role in the events of the Warcraft universe, particularly during the Third War. It was responsible for the devastation of the Kingdom of Lordaeron and the rise of the Forsaken, a faction of undead who sought to reclaim their free will. The Scourge's influence continues to be felt in the ongoing conflicts within the lore.