The horrifying Undead army, called the Scourge, consists of thousands of walking corpses, disembodied spirits, damned mortal men and insidious extra-dimensional entities. The Scourge was created by the Burning Legion for the sole purpose of sowing terror across the world in anticipation of the Legion's inevitable invasion. The Undead are ruled by Ner'zhul, the Lich King, who lords over the icy realm of Northrend from his frozen throne. Ner'zhul commands the terrible plague of undeath, which he sends ever southward into the human lands. As the plague encroaches on the southlands, more and more humans fall prey to Ner'zhul's mental control and life-draining sickness every day. In this way, Ner'zhul has swelled the ranks of the already considerable Scourge. The Undead employ necromantic magics and the elemental powers of the cold north against their enemies.

The Undead Scourge is a well-balanced faction that can field enduring ground forces and powerful air units. Their spellcasters possess a variety of powerful magics, including the dreaded ability to raise fallen allies and foes alike into an army of walking dead. In this way, the Undead can field armies more numerous than any other race in Warcraft III. Advantages Summoned Buildings The Undead do not build structures, but instead summon them into being. Once an Acolyte is told to build a building, it begins the summoning spell, and the building gradually appears. During this time, the Acolyte can return to its duties, since it does not need to stay with a building while it is being summoned. The Undead can also Unsummon their buildings and recoup a percentage of the gold and lumber cost originally used to summon the building. Corpses In addition to gold and lumber, the Undead Scourge harvest corpses as a tertiary resource. Corpses are not used for purchasing units or raising buildings, but instead are used to fuel some of the powers of the Undead. The Necromancer unit uses corpses to create Skeleton Warriors, while the Ghoul and Abomination consume corpses to rapidly restore health. Corpses disappear over time, but the Undead can store and create them in their Meat Wagon units, where they will not decay and can be unloaded for use when the need arises. Defense The Undead can have very tough defenses thanks to Their Spirit Towers and Nerubian Towers with Fortified Armor that can also be repaired during battle. Burrow/Stone Form Crypt Fiends can burrow under the ground making them invisible to the enemy and gaining increased health regeneration. Stone Form can be used to regenerate Gargoyles. Regeneration Undead can bring Obsidian Statues with them to regenerate their hit points and mana.