|Zebuxoruk is the lone occupant in the Void, a small cluster of islands interlinked by a handful of portals. Its outer portals point to various times in Norrath's history. More details about the Void and how it came to be can be found here.
As you progress through the six themes in this expansion, you'll gain access to "repaired" versions of "The Void" one by one. This is the original void as you see it upon first entering the Seeds of Destruction; there are six further versions. Details about this progression (as well as the expansion as whole) can be found here.