The Underdark

The Underdark is a plane torn away from the material plane, Rojopotis, after the War of Air and Fire. As the name implies, it is a dark place, like a deep cave. Humans, elves, and dwarves that sided with the House of Fire in the war were sent to the Underdark and became Tieflings, Drow, and Duergar respectively.

Getting to the Underdark
The Underdark is connected to Rojopotis via caves and deep ocean ravines. These connections come and go, and are most common during a dead (new) moon. Since it is a separate plane, time is not consistent between the Underdark and Rojopotis.

Places in the Underdark

 * The Sunless Sea - A vast ocean, connected to the Great Flat, and the Pontian Sea above, via an island north of Free Port. Home to the Temple of the Mad God
 * The Great Flat - A massive flatland with a low ceiling. Home to tiny white mushrooms, wild cattle-like creatures that graze on the mushrooms, and Tiefling nomads who herd/hunt the creatures
 * The Maze - a labyrinth of sharp rocks pointing in all directions. Connects the Great Flat to the Zurkhwood Forest
 * The Zurkhwood Forest - A forest of sturdy zurkhwood mushrooms. Home to spiders, driders, and the spider queen
 * The City of Makuro - Drow city built on the edge of the Zurkhwood Forest
 * Agorgiat's laboratory - built under Fort Didsky, connected by a tunnel and lake to the Zurkhwood Forest