Headcanon Theory #1
The Old Gods and the Evanuris are one and the same.
This is going to be expanded upon, but I just typed this up to explain it, and it’s the most coherent form so far. Developed over weeks of playing Dragon Age with @faerelden
My friend and I have been developing a theory over the last few weeks that the Tevinter Old Gods, and the Trapped Evanuris are one and the same.
We know that Tevinter took on a lot of Elvhen lore/language/places etc, it's not crazy to think that they would reappropriate the Elvhen pantheon, in a similar way to how the Romans took on and redesigned the Greek Pantheon to suit their own needs.
The Tevinter Magister's learned magic, when their Gods whispered to them from the Fade, where the Evanuris were conveniently entrapped.
The Old Gods forms are, conveniently, Dragons. You can't tell me that Mythal being able to shapeshift into a dragon is, then, a coincidence.
The Old Gods dragon forms are, conveniently, sleeping. Strangely similair to the way ancient elves would have entered Uthenera?
There are 7 Old Gods, and 9 Evanuris... but Mythal was presumed dead, and Solas wasn't trapped inside the Fade, that makes 7 and 7.
Solas is not pleased to find out that the Grey Wardens have been 'killing' Old Gods. This is where our theory gets a based a bit more on assumptions that canonical evidence.
We are told in game that when anyone other than a Grey Warden kills an Archdemon that it's soul passes to the nearest tainted body. When a Grey Warden kills an Archdemon, it is the closest tainted body, and that it somehow destroys the Archdemon... but it wouldn't be the first time Bioware has 'told' us something, only for us to learn more later, from a different source, that what we were believing was wrong for some reason. (Lyrium being a mineral springs to mind).
We also know that if the Old God soul jumps to Morrigan's child, it's no longer an Archdemon, but seems to be a purified version of the soul.
Add in that during Jaws of Hakkon, a DLC that revolves around killing a 'God' so that it's spirit/soul can be 'purified' or reset, and Faerelden and I believe that the Grey Wardens haven't been killing the Archdemons, so much as purifying their souls of the Blight, and simultaneous unlocking the door to the jail cell Solas threw the Evanuris into.
There are 2 unshattered seals, in the image from the announcement trailer, and 2 Archdemons left, and just maybe 5 purified Evanuris spirits floating around out there, somewhere, waiting to cause trouble. Permalink to Version 2: https://kita-lavellan.tumblr.com/post/189482711875/headcanon-theory-1