Board Thread:Lore Discussion/@comment-121.217.164.118-20130929050443/@comment-7153552-20130929071552

A prevailing theory, though I do not agree, is that they became one with Numidium. This is argued using the Arniel experiment in that he became attuned with the Dragonborn in a similar way that the Dwemer became attuned with their Brass God. It is one view, though not the one I choose to take.