From WoWWiki

For the equine nightmare, see nightmare.

The Emerald Nightmare (or "the Nightmare" for short) is a mobile area of corruption within the Emerald Dream. The Emerald Dream is not a place of total perfection. It can be shaped and twisted by dreams, usually without a sleeper’s knowledge. Sadly, nightmares are themselves a crafting of the subconscious and have given rise to their own place within the Dream. The Nightmare, as the denizens call it, is not a specific location, but a constantly roaming effect that travels about unpredictably. The skies above the Nightmare are constantly clouded, creating a gloomy, depressing zone that weakens and deadens everything it touches. The beautiful green vegetation is twisted into brown decay, while ordinarily peaceful creatures are corrupted into shadowy, mutated versions of themselves known as Corrupted Ones. The Corrupted Ones are vicious and cruel, hunting anything they can, even after they leave the Nightmare’s affected zone.

Worse still, some dream-travelers who enter the Nightmare — or are engulfed by its movements — become trapped in the Emerald Dream. They cannot leave, so their bodies back on Azeroth remain in a permanent sleep, slowly starving to death unless tended by helpful aides. While trapped, they are known as the Unwaking; they too are corrupted, until they will do anything to get back home. The Nightmare is believed to be slowly growing in size and power. No one knows its origins or why it has become so strong in recent years. Many druids are called to the Emerald Dream to help fight back its effects. So far, the green dragons have done what they can, though they dare not risk becoming themselves corrupted. The Eye of Ysera has not yet been approached by the Nightmare, but some fear that one day it will. And what will happen if the entire plane becomes covered by this terrible zone of decay…?^{S&L 147}

The origins of the Emerald Nightmare are not entirely clear, although it is certain that it is connected to the Old Gods. While some believe that the Nightmare is born of the Old Gods themselves, others believe that the powerful deity Hakkar the Soulflayer, the ancient Gurubashi Blood God, is the evil power behind the Emerald Nightmare. Hakkar is an old god to the trolls.^{LoC 59} Dwarven explorer Brann Bronzebeard speculates that Hakkar is an Old God or son of an Old God.^{HPG 185} The connection between Hakkar, the Green Dragonflight and the Emerald Dream is also hinted to adventurers in the Sunken Temple.

It is created using the twisted thoughts and fears of sleeping beings’ subconscious minds to corrupt the Emerald Dream. The Nightmare travels slowly through the Dream, leaving corrupted, vicious animals and Unwaking travelers in its path. The Night Elf druid Naralex and his former acolytes in the Wailing Caverns have been corrupted by the Nightmare - transformed into the wicked Druids of the Fang. Eranikus, right claw of the Green Dragons, was corrupted by the Nightmare. Even Ysera's most trusted lieutenants (Lethon, Emeriss, Taerar and Ysondre) have been warped by this dark power within the Emerald Dream. Malfurion fights at Cenarius' side against the Nightmare within the dream, but may have been turned into an Unwaking himself.

Memorable Quotes

• Malfurion Stormrage says: I fear for the worst, old friend. Within the Dream we fight a new foe, born of an ancient evil. Ysera's noble brood has fallen victim to the old whisperings. It seems as if the Nightmare has broken through the realm to find a new host on Azeroth.
• Eranikus, Tyrant of the Dream yells: My redemption? You are bold, little one. My redemption comes by the will of my god.