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. 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.
This skips all the content before the previous expansion to give players the most modern experience from a quest design POV (and to make sure the players are connected with the current storylines). It also ensures new players have a shorter leveling ramp—Blizzard says it will be as much as 70% shorter than it is currently to get from level one to the cap.
Alpha Beta PTR Vanilla 1.1.0 1.2.0 1.3.0 1.4.0 1.5.0 1.6.0 1.6.1 1.7.0 1.8.0 1.8.4 1.9.0 1.10.0 1.11.0 1.12.0 Burning Crusade 2.0.1 2.0.3 2.0.4 2.1.0 2.1.2 2.2.0 2.3.0 2.4.0 2.4.3 Wrath of the Lich King 3.0.2 3.0.3 3.0.8 3.1.0 3.2.0 3.2.2 3.3.0 3.3.3 Cataclysm 4.0.1 4.0.3a 4.0.6 4.1.0 4.2.0 4.2.2 4.3.0 4.3.2 Mists of Pandaria 5.0.4 5.0.5 5.1.0 5.2.0 5.3.0 5.4.0 5.4.7 Warlords of Draenor 6.0.2 6.0.3 6.1.0 6.2.0 Legion 7.0.3 7.1.0 7.1.5 7.2.0 7.2.5 7.3.0 7.3.5 Battle for Azeroth 8.0.1 8.1.0 8.1.5 8.2.0 8.3.0 Shadowlands 9.0.1
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.
The origins of the Shadowlands remain uncertain, but they have existed ever since mortal life first arose in the physical universe. They span all worlds, including Azeroth, on which Icecrown serves as an anchor to the Shadowlands. There are those who believe mortal souls are drawn into this dark place when they die, remaining there forever. Others hope their souls will go on to a brighter place rather than languish for eternity within the cold confines of the Shadowlands.
The Shadowlands are accessible upon death, where the player-character can roam, and can only be seen by other spirits. The Spirit of Tony Two-Tusk describes the Shadowlands as all grey and dark, swirling clouds. While Uuna was in the Shadowlands, she described it as dark and she was unable to see anything, though she could hear people interacting with her in the physical world. From within the Shadowlands, she could see the light of the naaru A'dal who was in the physical world, but it was so bright that it scared her. The moonlight at Lake Falathim allowed her to see a friend in the physical world.
Blizzard's new solution in Shadowlands is to return the level cap to its original value of 60 and to make current content appropriate for levels 50 through 60. New players start at level one, and they all play through a new introductory zone built for Shadowlands based on the quest design lessons Blizzard has learned over the years. Once they play through that introductory experience, they can then level up to 50 to catch up with current content by playing through the previous expansion (Battle for Azeroth) right away (from around level 10).
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.
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  The Power to Destroy.
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.