What realm of the dead is opened in World of Warcraft's 2020 expansion?

The realm of the dead opened in World of Warcraft’s 2020 expansion is the Shadowlands.

Shadowlands is the setting of the eighth World of Warcraft expansion, released on November 23, 2020. In Warcraft lore, it is the afterlife: a vast plane where the souls of the dead are judged and sent to different realms. The expansion turns that cosmological idea into explorable zones, including Bastion, Maldraxxus, Ardenweald, Revendreth and the Maw.

The story begins after Sylvanas Windrunner destroys the Helm of Domination at Icecrown Citadel. Her act tears open a rift between Azeroth and the Shadowlands, allowing mortal heroes to cross into the realm. That event is why the expansion is named Shadowlands rather than after one of its individual zones.

A common mix-up is Northrend, which is an icy continent in Azeroth introduced by Wrath of the Lich King. The Shadowlands is not a continent on Azeroth, Pandaria or Outland; it is a separate afterlife dimension in Warcraft’s universe.