Cale wrote on Jan 13
th, 2012 at 7:09am:
Probably neither, as Eladiun explained here:
So DDO2, almost certainly not.
Expansion to FR? Almost certainly not.
Expansion? Probably, with the information we have at hand this seems the most likely.
The fact that Turbine registered DDOforgottenrealms.com leads me to believe this is definitely an expansion to the Forgotten Realms and not a trip to Khyber (which we have done already in part 2 of the Xoriat line)
Khyber is Eberron's version of the Underdark, it is not the "Underdark" of the Forgotten Realms or Greyhawk" though. The world was formed when the progenitor wyrms changed their form into what they are now. Siberys and Khyber fought, leading to Siberys' body being broken into pieces. To stop Khyber, Eberron wrapped around him, and Siberys' broken body became a ring around them both. Siberys created the dragons, Eberron created humanoids and other "lower races", and Khyber created the "demons" of the world.
In FR and Greyhawk things like beholders, mindflayers and drow are natural residents of the "Underdark", whereas in Eberron only one subsect of drow has chosen to venture into Khyber, while most live in the ruins of the giant Empire either in violent confrontation with the giants that remain, or in servitude like the Sulatar drow who still serve the fire giants of the Sulat league.
Beholders and Mindlflayers populate Khyber because they and their Daelkyr masters were banished there by the Gatekeeper druids long ago when they invaded from Xoriat.
The other group that lives in Khyber are the Demon rajahs that once ruled Eberron and were spewed forth by Khyber itself. The most powerful demons, the Rajah's were sealed within Khyber by the combined force of the dragons and the Couatls who sacrificed themselves to bind the demons to Khyber.