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."
The experience curve is adjusted to make it faster than ever to prepare for the newest challenges, and each level along the way will provide more meaningful increases in progress and power. All expansion zones are getting more flexible, too; they'll be able* to scale to you and your friends while you level to 50, so it's easy to try a zone you've never played.
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.
The popular autobattler mode (games like Teamfight Tactics, Dota Underlords, and Blizzard’s own Hearthstone Battlegrounds) lets players draft units and place them on a chess-like board. The units then battle the units of another player. Between battles, players can buy new units, upgrade existing units, or rearrange them on the board. And according to Shadowlands’ most recent datamine on MMO Champion, World of Warcraft is getting a similar mode.
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.
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.
The Realm of Shadows may be the same World of Shadows as the one that becomes visible when a [Elixir of Shadows] is consumed. It may also have something to do with shadow magic and shades. Death knights, necromancers, and undead as a whole share a strong connection with the Realm of Shadows from many hints that can be seen in-game. In the death knight starting zone, death knights are given the task to enter the Realm of Shadows in order to gain their Deathcharger. Later on, death knights are eventually able to learn the ability [Raise Ally] which pulls their ally's spirit back from the Realm of the Dead and forces it back into their body. Upon doing so, a buff is applied to the player stating that: "A touch of the spirit realm still lingers..." This shows that death knights and necromancers both have a connection to the Realm of the Shadows/Dead to perform necromancy which furthers the idea that they actually are drawing their magical power from it.
During the Burning Legion's third invasion, the Knights of the Ebon Blade traveled to the Shadowlands to acquire the Aggregates of Anguish, five tormented essences of powerful souls - Admiral Proudmoore, Soulbinder Nyami, Grand Empress Shek'zeer, Grand Apothecary Putress and Archmage Arugal. Salanaar required these to conjure the Steeds of the Damned for the order's new Horsemen.