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.
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.
Sometimes, the spirits roam the Shadowlands without resting. It can be because their resting place wasn't complete, because of a battle in their resting place or because of the corruption of their resting place. To bring eternal peace to the souls, it is needed to destroy the source of corruption or by making a ceremony with items such as [Tuskarr Ritual Object]. A spirit in the Shadowlands can, with enough power over other souls, tear a hole into the living world once they are strong enough. This is how Jin'do returned to Azeroth.
The Shadowlands has long been referenced in World of Warcraft lore, but their origins and true nature remain a mystery. One thing is for certain; the Shadowlands are inextricably tied to death and decay. It stands opposed to the verdant spiritual realm of the Emerald Dream, which represents a vision of reality untarnished by corruption and mortal intervention.
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.
Sylvanas Windrunner, fallen leader of the Horde, has pierced the veil between Azeroth and the realm of the dead, setting in motion a series of events that threatens to upset the cosmic balance between life and death. World of Warcraft players entering the fabled Shadowlands will find the realms of the dead in upheaval. Under the normal order, departed souls were delivered to a realm appropriate to the lives they led, but now, all souls are being funneled into the Maw, where the most wicked are damned to suffer for eternity. As they seek to right the cycle and uncover the extent of Sylvanas' designs, players will forge bonds with the Covenants who hold domain over different planes within the Shadowlands.
The Shadowlands can be seen as a shadowy version of the physical world, and can be routinely visited as a spirit when player characters die. Governed by the Covenants, the four ruling realms of the Shadowlands are Bastion, Ardenweald, Revendreth and Maldraxxus (although countless others exist), which serve as the main setting of World of Warcraft's eighth expansion.