User blog comment:Vorred/Lost - Elegy - Uprising HD: October 2013/@comment-24051817-20131110170112/@comment-24051817-20131110213500

There's the entire possibility that he had a Tryna and a two Iden users.

Considering he's gone to the effort of already bringing their corpses back and replacing their souls, why wouldn't he want to twist the thing just a li'l further.

Users of the Iden can be known to begin to think that they're the previous inhabitant of the body. That means that Chaeus and Merall could be completely different people.

It clicks together, in my opinion.