Underdeep

The Underdeep is a Transcendent Realm layered with Zairis that was created and is ruled over by the Primordial Abraxas. Its nature and appearance are consistent with its creator's disposition - it is a blasted wasteland under a crimson sky, inhospitable to life other than the demonic, who thrive under the circumstances.

Overlap with Zairis

As with other transcendent realms of the Primordials, certain locations of Zairis have merged with the Underdeep at the corresponding coordinates - the most obvious of these are the Underdeep Blightlands, a large region of Dunieth that has been considered irreparably corrupted as a result. Other examples include pocket of overlap remaining from other demonic invasions, such as those found in the Blackwood region of Mithros.