The Undercity is the capital city of the Undead. It is built under the remains of the city of Lordaeron. It is foul and dark, with twisted gothic architecture and plague-green canals.
Captain Donald Adams, in the center of Undercity, sells Undercity Tabard which grants reputation in all dungeons.
Large amounts of Undercity reputation can be gained in the following zones: Arathi Highlands, Hillsbrad Foothills, Ruins of Gilneas, Silverpine Forest, The Hinterlands, Tirisfal Glades, Western Plaguelands. There are also daily quests available from the Argent Tournament, as well as Undercity Writ of Commendation from the Molten Front.
Non-Forsaken Horde players can purchase up to seven skeletal mounts from Zachariah Post in Brill--with Exalted reputation.
The Undercity was so named many years before the Forsaken claimed it as their own. Far beneath the palace of Lordaeron, the Undercity held the ancient crypts and catacombs of Lordaeron's royalty, as well as the city's dungeons and sewers. Although the Undercity was only intended for prisoners and the dead, the poorest of the Lordaeron people lived within. When the Alliance captured Orgrim Doomhammer, they sent him to the Undercity; sometime later he managed to escape and wandered for many years afterwards.
Lordaeron's Capital City stood for centuries, a monument to humanity's might. In the Third War, Prince Arthas slew his father, King Terenas, in Lordaeron's throne room and ransacked the city. He planned to use Lordaeron as his capital on this continent and ordered his minions to expand the catacombs beneath the city. Then the Lich King summoned Arthas to Northrend and the work was left uncompleted.
During Arthas' exodus, Sylvanas Windrunner broke free of the Lich King¡¯s control and took many banshees and other undead with her. With Varimathras' assistance she defeated the dreadlords that controlled the city and set her newly dubbed Forsaken to finish Arthas' job in the dungeons. The Forsaken carved the Undercity and now rule the surrounding countryside.
While the forces of the Horde and the Alliance were concentrated on a joint effort at Angrathar the Wrathgate, an uprising broke out within the Undercity. Demons of the Burning Legion and Forsaken rebels led by the dreadlord Varimathras and Grand Apothecary Putress managed to take control of the Undercity, killing several Forsaken and nearly killing the Dark Lady as well. In response the Horde led by Sylvanas Windrunner and Warchief Thrall attacked from the front entrance to reclaim the city. While the Alliance led by Varian and Jaina attacked from Sewers to restore Lordaeron to the Alliance. The ensuing battle ultimately killed both Varimathras and Putress, along with their fellow demons and Forsaken rebels.
With Patch 3.3.0, Thrall sent a legion of Kor'kron Guard led by captain Bragor Bloodfist, who replaced Varimathras, with Kor'kron Overseers replacing the Undercity Guardians, in order to ensure that the events of the Battle of Angrathar the Wrathgate never occur again. Some guardians still remain in the Sewers; it's unknown if this is an error or not.
After the death of Arthas, Undercity was attacked by the Emerald Nightmare's mists and shadowy warriors of nightmares. Sylvanas, half of the Forsaken and all Horde representatives were having nightmares. Sharlindra and some Forsaken witnessed Sylvanas' murmur and moments later, shadowy figures attacked Sharlindra and her followers - thus the whole Undercity was enveloped by the Nightmare.
The Undercity felt shakes but doesn't seem to have been too affected by the shattering, though the upper levels of Lordaeron have been re-designed to accommodate flying.
All the Kor'kron guards left, making only Bragor, now with the title of Hand of Warchief, being there. Under odd circumstances, the body of Overseer Kraggosh is now found in a cage.