Thread:KalKent/@comment-1713281-20130326200430/@comment-4651179-20130327042109

From the Appendix, comments by creator of entry:

"The story is told as if the Brilliant City is an alternate Earth, though it seems more of a higher plane of reality"

"A big part of the final arcs of X-Man involved the idea of a spiral pathway to the omniverse (...) with some realities being higher and more evolved (...) and other sbeing lower and more primitive (...). They specifically discuss Earth-616 as a median world, with the Brilliant City"

So, I guess it is a reality.