Ubisoft's official Might & Magic Heroes VI Facebook page has been updated with new concept art for the Necropolis and Inferno factions, as well as a Q&A that they recently did with Celestial Heavens. One of ten questions:
9. Is there a backstory to the Solmyr and Crag Hack in Ashan (mentioned by Narxes and Isabel in the H5 campaigns), or were they really nothing more than a bit of name-dropping?
In a world of millions of people there are many, many names. Some of them could simply be coincidental; others have such power that they may reverberate across all the possible worlds of reality... But to give you a more straightforward answer, yes they're part of Ashan lore and you may meet them one day.