Ghostlands
The Ghostlands was the name given to the region of the Eversong Forest in Quel'Thalas that became the domain of the Dusk Court of the sin'dorei. It was blanketed in a shroud of night using the magic of the the Nightveil Pearls that were created by Varden Dawngrasp and other blood elf magisters to make the region safe for its vampyric denizens, and as a result the region was gradually transformed into a dark mirror of Eversong.
Geography
As a region blanketed in night, the Ghostlands were drastically altered from what they were before. The undead sin'dorei in the region still possessed the kinship they had with the sun, Belore, in life, thus the magic that coated the region allowed the sun to shine still, albeit with a deep red glow that was safe for those sensitive to the light and cast a crimson wave over the region during the day. When the sun set, the region appeared as a normal night.
Due to the change in sunlight, the flora of the region was magically adapted to thrive in its new environment. Many trees that once had golden leaves were stained a deep crimson, and glowing, anima-feeding plant-life was developed in the pursuit of creating a more sustainable means for the san'layn of the Ghostlands to feed. Rivers of anima carved through the region, which served to feed both the new flora and its other denizens.
Due to the presence of undead and other monstrous horrors, the Ghostlands were known for a certain danger if they were traversed without a guide, and the sin'dorei of the Dusk Court did little to dispute such claims. While the undead themselves were not an explicit threat, the twisting trees and deep groves made it so that travelers could easily get lost, and the wildlife could easily seize those that did.
The northern border of the lands transitioned into a twilight state during the day as the Ghostlands faded into the golden trees of Eversong.