Undertown was the bustling main city of the Edge during the First Age of Flight. It was founded in the Second Great Migration on the principle of free status for all, intended to be a haven for those seeking escape from the oppressive slavery and danger of the Deepwoods. Attempting to enslave an Undertowner was a crime punishable by death.
Undertown during the Quint and Twig trilogies
On the side of Undertown near the Mire, factories and foundries operated. The side nearer the Stone Gardens was called the Western Quays, and was dotted with large, opulent palaces. The Boom-Docks was the part of Undertown where sky ships arrived and departed. In the very centre of Undertown was the Anchor Chain.
Many Deepwooders believed Undertown to be a place of harmony and freedom, where the streets were paved with gold and all races were respected. In reality, Undertown was a very difficult and cut-throat place in which to live and work. The League of Free Merchants controlled the entire city, and were constantly quarreling. The taverns and slums of Undertown were filled with a variety of peoples from all over the Edgeworld. The weak and slow never lasted long in Undertown.
Undertown during the Rook trilogy
During the events of the Rook trilogy, Undertown had changed drastically. The Leagues had lost their power and collapsed, and Goblins ruled the city. Diseased chunks of the New Sanctaphrax rock had crashed down and destroyed the Western Quays, creating Screetown. The goblins, led by General Tytugg, had enslaved the Undertowners, forcing them to work on building and enforcing the Sanctaphrax Forest. The librarians, those who opposed the Guardians Of Night, hid underground in the sewers. Undertown was destroyed when Vox's Baby was launched, creating the Dark Maelstrom.
Undertown in The Immortals
The crew of the Archemax returned to the ruins of Old Undertown twice; once on their original journey to the Edge, and the second in their search for Ifflix Hentadile. They found it overgrown and reclaimed by lush vegetation, with the buildings little more than ivy-clad rubble. On the first voyage, Cirrus Gladehawk found the stone head of Vox Verlix and retrieved it as a present to their benefactor Quove Lentis.