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.
But we know that the mission table feature will return in some way, thanks to a Hazzikostas interview with Twitch streamer and professional World of Warcraft tank, Sloot. In the interview, Hazzikostas confirmed that mission tables are present in Shadowlands, and that Blizzard wants it to be something you can do on your phone, rather than a front and center feature. Hazzikostas also stated that the team is looking to evolve the gameplay and offer more for players.
Sometimes enemies will drop Phantasma, a currency that is unique to Torghast. You may also find Phantasma from Anima Powers or breakable objects. Your Phantasma all disappears as soon as you leave Torghast. Occasionally, you may find a Broker, a Phantasma vendor within Torghast, who will allow you to spend your Phantasma to buy Anima Powers, along with other consumables that will aid you on your run.
When the time comes to ally with one of these four, you’ll want to carefully consider the abilities the Covenant will provide you. Each provides two abilities tailored to the theme of the Covenant. The first of these is the Covenant’s signature ability, which is available to all Covenant members regardless of class, race, or specialization. This ability helps you explore and engage with the world in new ways, and gives you a unique tool to help solve the problems you encounter in the Shadowlands. The second of these abilities is specific to your class, and gives you a new spell or power to use in combat.
A new army of the dead rises: to combat Sylvanas' assault on Icecrown, Bolvar Fordragon— the revered former paladin who took on the mantle of Lich King to keep the Scourge at bay—has raised heroes from among all the peoples of Azeroth to bolster the Death Knights of Acherus. With Shadowlands, pandaren and all allied races will now be able to become death knights.
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.