Its existence is known by many, but it's accessed by only a scant few of the assorted races of Azeroth. Long ago, Malfurion Stormrage learned the ways of the druid from the Ancient Cenarius, and through that process, learned to travel through this mysterious place. Once under the protection of Ysera, it's currently undefined just how much influence the Aspect of the Green Dragonflight now has over the mystery that is the Emerald Dream -- but for years, it's been a haven for druids, and druids alone.
Over several expansions and through several novels we've seen the progression of the Emerald Nightmare -- in the novel Stormrage, the Nightmare was by and large defeated. In game, we rarely saw mention of it, although one or two quests happened to mention Malfurion's dilemma within the Dream, and a few quests actually sent us inside. In all honesty, the most we've seen out of this content in-game were files and exploration videos of old zones that were never developed. Yet there's something really fascinating about the Emerald Dream, something that captures the imagination and has many players clamoring for an expansion featuring that content.
So what does any of this have to do with Draenor?
Today's Know Your Lore is a Tinfoil Hat edition. The following contains speculation based on known material. These speculations are merely theories and shouldn't be taken as fact or official lore.