Bough of Shadows

The Bough of Shadows, originally called Silvergale, is a dark forest surrounded by low mountains on three sides, with a small passage by a lake on the southeast side. The Bough rests in the domain of a particularly powerful corrupted holy spring of the Aeinadan, which gives the demons in the forest considerably more power (and consequentially, hunger), than most demons. The demons that lurk there wait in ravenous hunger for the next unlucky traveler to pass through.

Daegon made a pact with these demons that inhabited the Bough: protection from foreigners and access to demonic power, in return for the ability to inahbit elven bodies. The demons agreed, granting Daegon and his clan powers from demons that had slumbered for ages. The Bough of Shadows became infamous for the Dark Elves that lived there, and rumors spread about the followers of Daegon. They took up a new name to separate themselves from the rest of the Elvenhan; they called themselves Daegon'hai, and prospered in relative peace until the Fifth Age.

Speculation
There are whispers that Edvens herself tamed the Old God beneath the Bough, though it is unknown whether she killed it and took its place, or cleansed it of ancient evil.