The Darkwood is not strictly a forest, rather a name that has risen up for a region of Fey which the Dark Fey call their home. Named for the tangled woods that border this land on all sides, the Darkwood's true appearance beyond this border is as much of a mystery as the nature of the Fey who live inside of it. It would be a misnomer to call the denizens of the Darkwood the "evil fey" however, despite their often cruel and capricious nature. Rather the dark fey are those who are bound to the more esoteric powers of the world, such as that of dreams, memory, and binding to name a few examples.
Nevertheless, the Darkwood and the Fey who reside there and at the very least feared, if not outright reviled by the Fey of the Courts.