Are underground entrances to Khyber considered portals? What separates Eberron from Khyber-physically? Is it like crossing a State line-“Welcome to Khyber” or is it shielded from sight, must break some barrier to traverse it. “Khyber” has different meanings. It’s both the physical underdark—any vast subterranean cavern or system of tunnels—and a network of demiplanes filling a role similar to the Abyss.
— Keith Baker (@HellcowKeith) February 1, 2019
What’s required to pass through a portal to a demiplane in Khyber depends on the portal.
— Keith Baker (@HellcowKeith) February 1, 2019