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.
In previous expansions, entities like the Loa of Death Bwonsamdi, ex-Forsaken Queen Sylvanas Windrunner, and corrupted titan watcher Helya all have spoken of the Shadowlands, and for some, the desire to conquer it. Sylvanas' character arc throughout Battle for Azeroth ends with her seeking to control death itself, indicating that she will play a pivotal role in Shadowlands.
In classic World of Warcraft expansion "Wrath of the Lich King," Alliance soldier Bolvar Fordragon replaced Arthas Menethil as the avatar of the Lich King, ruler of the undead Scourge on Azeroth. Pledging to keep the ravenous dead at bay, Bolvar was sealed into the Frozen Throne, entombed in the haunted armor of the Lich King. It looks as though Bolvar is set to play a central role in the next WoW expansion, tentatively dubbed "Shadowlands."
Covenants grant two additional gameplay abilities, one being class-specific. It alters your playstyle. Covenants grant unique armor styles and special capes that look a little more like accessories. Titan-like Kyrian capes look more like angel wings, for example. Each Covenant has a unique campaign similar to those found in Battle for Azeroth and Legion.
The spell called "spiritual projection" or "astral projection" brings the caster to the Twisting Nether instead of the Shadowlands; and the Twisting Nether is also referred as "realm of ghosts". However, both planes don't appear to be related, as Outland is floating on the Twisting Nether, but the Shadowlands can be reached in Outland in The Burning Crusade.
Ascend the Tower of the Damned: at the heart of the Maw lies Torghast, Tower of the Damned, a cursed otherworldly prison where the wickedest souls in the universe are locked away. Highly replayable and inspired by roguelike games, heroes are invited to explore its ever-changing halls and chambers and do battle with the minions of the Jailer, Torghast's vile ruler. Those who brave its trials can claim legendary treasures and help free the heroic spirits wrongfully trapped within.
Blizzard started testing World of Warcraft: Shadowlands last week, and is slowly allowing players in to test new zones and features. While the “Adventures” mission table isn’t available on the test realm yet, we should see some version of it pop up in the next few months. Whether it actually turns out to be an autobattler or not remains to be seen.
Spirit healers decide when it's time for a mortal soul to pass into the Shadowlands. When a mortal dies and their soul crosses the veil between life and death, it is shepherded by the kyrian to Oribos so that they can be judged by the impassive Arbiter. All of the soul's contents—deeds, misdeeds, thoughts, accomplishments, and failures—are instantly laid bare before the Arbiter, who then judges in a mere instant and sends the soul off to one of the infinite realms of the Shadowlands, each of which is ruled over by a powerful Covenant. The Covenants are ancient and powerful orders who have existed since the Shadowlands were shaped long ago, and who bear sacred duties to help maintain the afterlife's ecosystem. Not every soul is filtered into the main four Covenants. Each soul brings with it a vital force known as anima, the product of all of the soul's experiences and actions in life. Anima is the lifeblood of the Shadowlands, making trees grow and rivers flow and is the source that's drawn upon to conduct the magic of death. Great souls—both good and evil—have a lot of anima, while those who have lived humbler lives have less. Four of the realms—Ardenweald, Bastion, Maldraxxus, and Revendreth—are especially vital to the functioning of the Shadowlands. However, there could be infinite afterlives, some small and tailored to a single person while others are vast and full of either splendor or torment. Between each realm is a cloudy space which was once rich with streams of anima connecting the different domains, but the current anima drought has caused the realms to become cut off from one another, breeding fear and mistrust among the inhabitants.