Shademurk Forest

The Shademirk Bog, also known as the Shademirk Forest, was a corrupt, thickly-wooded swamp in the Feywild. A series of enchanted rivers, collectively known as the Gilded Run, surrounded the Shademirk Bog and prevented the corruption from spreading elsewhere in the Feywild.

The trees of the Shademirk Bog had thick trunks with sagging canopies like weeping willows. Black, sticky, tar-like ichor coated the vegetation and seeped into the ground. This viscid substance could impede foot travel; Scanlan, for example, tired from repeatedly extracting his feet from the tar.

The source of the ichor was actually a corrupted archfey name Saundor. After Vox Machina slew him, the black ichor that seeped out of the plants of the Shademirk Bog ceased flowing and started hardening like amber. Keyleth used Commune with Nature and discovered that the surrounding plants began relaxing upon Saundor's demise.

When Vox Machina returned to the Feywild about a year later, they saw that the corruption had entirely receded. The area looked like a normal forest by Feywild standards. The Shademirk Forest seems to have some level of intelligence, as one of the trees bent its branches in a certain way to allow Vox Machina to rest in them, apparently grateful for their part in defeating Saundor.