So with this discussion about lyrium and dwarves, some more of my crazy speculation...
What if Elgar'nan was the one to betray Mythal? He decided he wanted absolute power and set out to get rid of the rest of the pantheon. But he didn’t plan to outright murder them. Instead he poisoned the lyrium, corrupting and tricking the Gods - who we actually suspect may be are powerful mages - with red lyrium.
[This continues with my theory about the betrayal of Mythal, working with Fen’Harel to quarantine the rest of the pantheon to protect them.]
But! What if at least one other member of the pantheon sought another method to protect themselves from Elgar’nan and his poisoned lyrium? He (because I’m speculating this was June), found a way to cut himself off from the Fade, the need for lyrium, and his followers/slaves followed suit. It was this break resulted in the dwarven race.
Solas: Dwarves are the severed arm of a once mighty hero, lying in a pool of blood, undirected, whatever skill at arms it had gone forever. Although it might twitch to give the appearance of life, it will never dream.
This is not just a metaphor or a bit of history Solas is sharing. He knows exactly who that mighty hero was. It was one of his contemporaries, a member of the pantheon who took drastic measures to save himself from the corruption that would taint their blood..
Solas: Are there many tricksters in dwarven literature?
Varric: A handful, but they're the exception. Mostly they're just honoring the ancestors. It's very dull stuff. Human literature? Now there's where you'll find the tricky, clever, really deceptive types.
Solas: Curious.
The banter doesn’t just serve as a wink and a nod to the player about his true identity. Solas is actually trying to find out if he specifically - or at least a reference to his persona - is counted among the ancestors in dwarven histories. If one of the pantheon created the dwarven race, the Ancestors could very well be the one and the same as the Elven Gods.
Then further down the rabbit hole... it's interesting to speculate if Elgar'nan, Mythal, Fen'Harel and whoever turned Dwarven Ancestor, were not imprisoned, that leaves 8 other Gods who were (including the Forgotten Ones). Coincidentally, rumour has it that there could be one lost Old God making a total of 8 Old Gods... Further, further down is Elgar'nan really the Maker, which ties in the theory about Mythal/Andrasta. You should probably turn back now, my ideas are getting to be too crazy.