The Shadowlands were originally intended to be a fully playable zone in World of Warcraft, designed for high-level play. The idea was that as deceased characters made their way back to their corpses, they'd see high-level players battling creeps in the area, which would inspire lower level players to increase their character level so they could experience the zone for themselves.[69]

The final destination of the spirits of the deceased remains a mystery to the priests and philosophers of Azeroth. However, as spells such as [Resurrection] can reunite a dead body with its spirit, and a majority of living creatures from the tauren to the troll shadow hunters claim they can communicate with and call upon the power of the spirits, a widely held belief is that the spirits of the dead remain on the Material Plane — in an immaterial state that can only be altered or contacted through the use of magic.[63]
Shadowy Tormentors inhabit this dimension, and emerge from it to torment death knights such as Koltira Deathweaver. The Lich King originally kept them at bay, but after the Knights of the Ebon Blade left his service, the tormentors are now loose upon them. He even appears in the World of the Dead, as he calls it, riding a frost wyrm during  [73] The Power to Destroy.
Furthermore, upon the Lich King's death he even spoke of "Seeing only darkness before him" while Sylvanas Windrunner said the same in Silverpine Forest after being risen from the dead by the Val'kyr. This may hint that because undead, death knights, and necromancers are connected to the Realm of Shadows when they die (again) they actually become apart of the Realm of Shadows and are forced to wanders in its dark mists for the rest of eternity. If this is so, then it can also be implied that when a death knight is given his/her own personal runeblade, the runeblade is actually used to bind the individual to the Realm of Shadows in mind and body, making it impossible to ever be rid of the death knight curse. In Howling Fjord, players are even able to witness the Lich King himself standing within the Realm of Shadows with two Val'kyr. The idea that necromantic magic and death knight runes drawing power from the Realm of Shadows itself is not yet proven, but it is heavily supported by in-game quests and lore.
Explore the Realm of the Dead: for the first time ever in World of Warcraft, players will cross into the Shadowlands and experience the wonders and horrors of the afterlife across five new zones—the gleaming fields of Bastion, the scarred battlefields of Maldraxxus, the eternal twilight of Ardenweald, the opulent keeps of Revendreth, and the horrific Maw.
Since World of Warcraft’s 2014 expansion, Warlords of Draenor, the MMO has used some kind of mission table for players to gain passive bonuses while logged out of the game. Two years later, Blizzard introduced a mobile app, which let players send followers on important missions while far away from their computers. But with the upcoming Shadowlands expansion, it seems Blizzard is trying something a bit different with missions: an autobattler.
Claim a covenant's power: players will be called upon to forge a bond with one of four covenants that rule Shadowlands' new zones, setting the tone for their journey through the expansion with a full covenant campaign. As they level up, they'll get new abilities based on their choice, including class-specific abilities for each Covenant—as well as developing soulbinds with specific covenant members, which grant them access to that character's specific traits and bonuses.
Beings of death are ancient and powerful, and it is dangerous to meddle in their realm. When Odyn peered into the Shadowlands, he saw some of its inhabitants: souls in torment, the husks of the dead, ghostly wraiths with no face, and others with no form, all made of death itself. This was enough to frighten even him.[41] Several races in the Shadowlands, such as the kyrian of Bastion, are souls of deceased mortals who have been transformed to serve a new purpose. If one of these former mortals is killed in the Shadowlands, they die permanently. Other creatures—such as dredgers and stewards—are endemic to the Shadowlands and are naturally born from the magic of death to serve the different realms and help facilitate the process of the afterlife. If one such creature of death is killed, their energy is recycled back into the Shadowlands, and eventually another member of the same race will manifest to take the place of the one that was killed.[42][43]