The dungeon crawl video portion seemingly related to Labyrinthos seemed to have exact Amaurotine architecture and concept crystals in it.
*Wild speculation ahead, WATCH FOR FALLING ROCKS*
It may be that prior to Nyunkrepft's ark saga, the Sharlayans were sundered ancients in stasis pods in the Labyrinthos, getting by on survival means and food. The 6th calamity saw resources dwindle, and so they had to make a mock civilization topside in order to continue surviving.
It may also be that Nyunkrepft Nyunkrepftson was merely a thief who stole Sharlayan's ark, which they were going to use to survive while the Labyrinthos drained the water/recovered. Him being founder for the topside shell civilization is a cover story. His name roughly translates to Nineclaw Nineclaw-Son. To have nine fingers or claws is Ye Olde slang(that predates Ye Olde) meaning thief, as in ancient times in our own world thieves had a finger cut off to mark them.
What's truly surprising to me is that no in game civilization has had an interest in the ark. I suppose it's because it's high up in the mountains with no real way to move it, but then it is also literally chained/anchored into the rock, and has a thin gold aetherial field film coating its surface. You'd think a 1500 year old, perfectly preserved sailing ship would merit some sort of investigation. Certainly more than literal ruins and things from not as long ago in other places.
I could also imagine some vagueness. Perhaps they were originally in stasis on the moon, and used the 6th calamity as cover to come down from it. The story of coming from their original home to somewhere far away... only to go back there really does draw a lot of attention to itself.
