Something doesn't add up regarding the connection between Amdapor and Norvrandt...

[geekgirl101]

It's not a sin eater, it's an Amdapori golem that somehow happens to be identical to one. (Note that it remains as a stone statue after the battle is over.)

Also worth noting in the hard dungeon: in the area leading down to what was originally Diabolos' arena (named "the Arrested Darkness") we encounter several "Rift Dragons".

The Rift Dragons did in deed capture my attention, making me question whether this hinted that the Amdapori mages were perhaps meddling at opening rifts. This springs to mind the 2 mages on the First who were being taught how to open up rifts, I forget their names.

My theory on the final bosses at the dungeon were that they were perhaps sin eaters at one time and once they had expended their energies turned into stone, but I got nothing to back that theory up so I was maybe wrong about it. There's not a huge amount of detail about what happened during the Fifth Astra Era that I could find other than it was a time when Eorzeans first discovered magic and were dabbling with black magic, whilst mages in Adampor developed white magic in order to counter them. What I didn't do was look up and read up about the following era, the Sixth Umbral Era, which explained the use of void magic, where Diabolos came from, and a fair amount of detail in what caused the era to end. I guess I should've really done my homework a lot more than I did and not just relied on the one source I was using last night that didn't give me much to go by.