In Dragonflight Patch 10.1: Embers of Neltharion, players will follow newly freed Primal Incarnate Fyrakk the Blazing deep beneath the Dragon Isles to Zaralek Cavern, a massive underground zone and setting for the next Dragonflight campaign. Described as bigger than Zereth Mortis, players will be able to Dragonride throughout the sprawling complex, as they race uncover ancient secrets of the Black Dragonflight.
Zaralek Cavern is made up of three distinct biomes — crystalline caverns of lofty formations of stalagmites and stalactites, sulfur pools which serve as the dumping grounds for Neltharion's failed experiments, and twisted spires of volcanic lava floes which the Djaradin Elders call their home. As an entirely underground area, the zone feels very reminiscent of Deepholm, which also bore the marks of Deathwing's time there, giving the two zones a lot of thematic similarities.
Inhabitants within the new zone include the Niffen — friendly mole people who will feature their own renown track for players to build reputation, as well as the Drogbar returning from Legion to lift heavy things engage in high-speed snail racing! Players will also recognize the Djaradin, who will serve as one group of antagonists in the new zone. Their elders settled the Cavern long ago and it serves as their true base of power in the Dragon Isles.
Read more on wowhead.com