Feydark

The Feydark was the echo of Toril's Underdark in the Feywild.

Description
like most parts of the Feywild, the Feydark was more majestic and fantastic than its natural counterpart. . Inhabited by the fomorians, a fey echo of the titans, the Feydark was a cavernous world of maze-like tunnels and portals linking to Toril and other planes.

Geography
The geography of the Feydark was similar to that of the Underdark. A maze of tunnels linking caverns permeated the Feydark. However, unlike the Underdark, the Feydark was home to terrain commonly found on the surface, such as forests and swamps.