Board Thread:General Discussion/@comment-3134600-20140811224344/@comment-3134600-20140822225533

Those are some excellent points, which still beg the question of what Stone it is. The Aether's known abilities have little to do with Mind or Time, so that leaves Soul: if turning light to dark is a euphemism for the mortal soul. The Aether bonds to a living host, so it could be it.