World of Warcraft: Wrath of the Lich King

Players last visited Northrend in "Warcraft III: The Frozen Throne," when Arthas Menethil fused with the spirit of Ner'zhul to become the Lich King, one of the most powerful beings in the Warcraft universe. He now broods atop the Frozen Throne deep in Icecrown Citadel, clutching the rune blade Frostmourne and marshaling the undead armies of the Scourge. (gamefaqs)