One of the playable races in
Warcraft III.
The Undead army, known as the Scourge, is one of the newest concepts in the *craft franchise. They combine a few ideas from previous games, with a few extra new ideas that weren't technically possible, making them a versatile, competent force that has a few caveats for prospective players.
The Undead are first and foremost one of the most difficult races to play. They require large amounts of pracitse, micromanagement and skill, and are also the only race with known faults. Their Acolytes summon buildings, not build them, much like the StarCraft Protoss do, allowing fast base building. However, the Undead have a fantastic reliance on blight - corrupted patches of ground that spread from their buildings. Only two buildings can be summoned on "normal" ground - the Necropolis, serving as the bases "Town Hall", and the Haunted Gold Mine, which can be summoned on to uncorrupted mines around the map. Each of these buildings, once complete, generate a radius of blight, allowing further buildings to be summoned.
Their units range from the versatile lumber carrying Ghoul to viscious spellcasters like the feared Necromancer, to massive beasts of war - the filthy Abomination or gruesome Frost wyrm. Overall they can field an army that is varied and complementary - they are good support armies, and the very best can take anything thrown at them.
As background information, a new expansion does not need a town hall as other races do - a Haunted Gold Mine is simply summoned and other buildings summoned once the mine is complete and the radius of blight is generated. Gold is magicked away from the mine automatically by up to five Acolytes. Unlike other races, the Acolyte remains stationary outside the mine at all times, making their mines quite susceptible to attack.
The Undead also have an easy path to towers - their "farm" building, the Ziggurat is able to be upgraded to a Spirit Tower with a piercing attack that is available once a Graveyard has been completed. Their upgraded town halls (Halls of the Dead and Black Citadel) also have piercing attacks, making even an undefended base quite deadly to the unprepared.
Additionally, the Scourge also make use of a "tertiary resource" - corpses. Once an enemy is slain, their body remains on the ground for 88 seconds, allowing use by a number of units - the Death Knight can truly Animate Dead, passing control of the deceased for 2 minutes; the Necromancer can Raise Dead the corpse in to 2 Skeletons, tenacious but fragile fighters, and finally the humble Ghoul can Cannibalize them to regain HP at a fantastic rate.
For completeness, I have included the summary statistics of both buildings and units here for ease of reference. These stats were taken directly from the public pages of www.battle.net/war3, the definitive, official online reference for Warcraft III. As a guide, Cool represents Cooldown - how quickly a unit can do another action, Ground represents their ground based attack damage, as does Air in relation to airborne attackers.
Hero Role Spells
Death Knight Melee Death Coil, Death Pact, Unholy Aura, Animate Dead
Dreadlord Support Carrion Swarm, Sleep, Vampiric Aura, Inferno
Lich Spellcaster Frost Nova, Frost Armor, Dark Ritual, Death and Decay
Unit Gold Wood Food HP Armor Armor Sight Speed Build Attack Weapon Ground Air Cool Range Building
Acolyte 90 0 1 180 Medium 0 80/60 220 15 Normal Normal 9.5 None 2.5 Melee Necropolis
Ghoul 140 0 2 330 Medium 0/6 140/80 270 18 Normal Normal 13/17.5 None 1.3 Melee Crypt
Crypt fiend 250 40 3 550 Small 0/6 140/80 270 30 Pierce Missile 29.5/40 None 2 55 Crypt
Gargoyle 220 30 2 400 Medium 5/11 160/80 270 35 Pierce Normal 17/23 51.5/71 2.2 30 Crypt
Abomination 280 70 4 1080 Large 2/8 140/80 270 45 Normal Normal 36/48 None 1.9 Melee Slaughterhouse
Meat wagon 270 65 4 380 Medium 2 140/100 180 45 Siege Artillery 79.5/108 None 4 100 Slaughterhouse
Necromancer 170 20 2 230 Small 0 140/90 270 30 Pierce Missile 10.5/15.5 10.5/15 1.8 60 Temple of the Damned
Banshee 180 30 2 210 Small 0 140/80 270 35 Pierce Missile 13/19 13/19 1.5 50 Temple of the Damned
Frost wyrm 450 120 7 1100 Large 0/6 160/80 220 60 Pierce Msplash 95/113 95/113 3 30 Boneyard
Shade N/A N/A 1 250 Small 0 190/80 270 15 N/A N/A N/A N/A N/A N/A Sacrificial Pit
Skeleton N/A N/A 0 180 Medium 1/7 80/60 270 N/A Normal Normal 14.5/19 None 2 Melee Necromancer
Infernal N/A N/A 0 1500 Large 6 140/80 320 N/A Chaos Normal 54.5 None 1.35 Melee Dreadlord
Building Gold Wood HP Armor Armor Sight Build Attack Type Ground Air Cool Range
Haunted Gold Mine 300 170 800 Fort 5 90/60 100
Necropolis 350 0 1500 Fort 5 90/60 120
Halls of the Dead 310 150 2000 Fort 5 90/60 120 Pierce Missile 45.5 45.5 1 80
Black Citadel 345 150 2300 Fort 5 90/60 120 Pierce Missile 54.5 54.5 1 80
Crypt 280 50 1300 Fort 5 90/60 60
Ziggurat 150 50 500 Fort 5 90/60 50
Spirit Tower 120 40 550 Fort 5 160/80 35 Pierce Missile 29.5 29.5 1 70
Altar of Darkness 300 100 900 Fort 5 90/60 60
Graveyard 250 0 900 Fort 5 90/60 80
Slaughter House 240 80 1200 Fort 5 90/60 80
Temple of the Damned 225 80 1100 Fort 5 90/60 70
Sacrificial Pit 200 80 900 Fort 5 90/60 45
Boneyard 350 125 1500 Fort 5 90/60 80