Underdark

What is the Underdark?  In Forgotten Realms, the Underdark is the series of caverns and caves that house the (mostly evil) races that live underground.  While I like the idea of an Underdark for Arenthyor, the name "Underdark" has always struck me as being Surface-centric.  I mean that a drow, for example, who has lived her entire life in the lightless depths and the comforting enclosures would not consider herself, her world, to be "Under", nor "dark", for those are concepts that would be foreign to her.  She would consider her world to be the center of the universe, not below something that she has never experienced (the surface world) nor would she comprehend the world of light in order to recognize that she lives in darkness.

I think there needs to be a new name, a better name for the Underdark in Arenthyor.  One that takes a resident's point of view of describing the world.  One that recognizes the security provided by having a cold cave wall at your back.  One that assumes that darkness is not the absence of light, but rather that there are shades of darkness that can measured as we can see the progression of sun across the sky.

Problem is...I don't know what that is.  I invite you to send me your comments, either through here or through the comment form on the homepage.  Let me know what you think the name of Arenthyor's Underdark should be.

Why this discourse about the Underdark?  I thought you'd never ask.  Well, because as development of the world continues, it is high time those races get a little love.  Read on, if you dare.

***SPOILER ALERT*** 
If you don't play an Underdark race, the below contains metainformation that your character may not have knowledge of in-game.  Please roleplay accordingly.  It is likely that learned characters (wizards) or certain races (elven) may know this information, but few others.

Up until this point, those races preferring lightless depths and evil machinations (you know who you are) have been sorely lacking in a place to call home.  Enter the city of Cheath Er'Sadria, home to the worst drow, illithids, cave goblins, deep halflings, dueargar, and svirfneblin that has ever been thrown together.  Of course

Brief history:  An ancient city under the crust of the world of Arenthyor, Cheath Er'Sadria was devastated by the Riftening as the rest of the continent of Arenthyor was when the world was split asunder.  Before the catastrophe, it was a sprawling lightless metropolis in an enormous cavern miles wide and high.  When the Riftening shook the world, a chasm opened up and swallowed half of of the city.  Of course, the drow were quick to recover, since the half of the city that fell away was mostly the ghettos that housed the "lesser" inhabitants.  The drow and illithid quarters were largely untouched and continued to thrive over time.  The ghettos, on the other hand, never recovered and to this day the inhabitants live in ruined buildings and scratch out existence on the fringe of Cheath Er'Sadria society.

Assassination, servitude, dark dealings, betrayal, and blackmail are the most valuable currency in this world.  Coins can be stolen, but information?  Information must be extracted.  Usually with a serrated blade and accompanied by much screaming.  Welcome to Cheath Er'Sadria.