Hey there! So, when I get into something I have a tendency to really get into it and after starting to replay through all the DA games, I got into the mood of writing lore discussion bits like this. This won't be some detailed examination of any and all hints throughout all the games (there are people far better at doing that than me) but, instead, I thought of writing down a theory I had for Titans.

So, we know that Titans are ancient, powerful, and existed prior to Elven people become as strong as they did as it is mentioned how Elven people fucked over Titans, Dwarves, sucked power out of Titans, and then imprisoned them. But we also know that Dwarves used to be different: taller, seemingly with magic powers and "whole". So, here is my idea: what if Titans were the real creators of the world as we know it while Elves and Dwarves used to be one people, either serving Titans or simply being creations of Titan. Then, some of those people decided that they wanted more and began waging war on Titans in search of power. Some of them tried to defend Titans yet were defeated and cast underground, sealed and becoming what we now know as Old Gods. Others, after defeating Titans, gained power and became what then became Evanuris. Titans were then sucked dry, as much as possible, before they sealed them away, knowing that they might not have a second shot at defeating Titans again. And this event is what led to those people being divided into two: Elves and Dwarves. If you want to take this a step further, perhaps before, those people used to be dragons as Old Gods (or archdemons) always come in a form of a dragon.

Now, as you saw in the title, I also mentioned Qunari. From what I know, we know little about the religious views of the Qun. You also might know that in the world of Dragon Age, many various religions overlap and there is a sense that they all are correct in one way or another: some people theorized that the Maker could've been Solas, that Golden City was the capital of Ancient Elves and so on and so forth. We know very little about Qun's religion (it was commented that Qun is not atheistic) and we know little about Kossith as well. To make, the idea that makes the most sense is that Kossith were Avvar peeps who were experimented on by Elves using dragon blood, turning them into what they are now and thus forcing some of them to create Qun to control themselves.

We know that DA4 will drop some fat lore bits about Elves and, possibly (hopefully) about Qunari as well but, as a last piece of food for thought, here is something: Scaled Ones. Gimme my reptilian gf Bioware, you cowards.

Edit: I needed to put it here somewhere but I guess I forgot when I was writing it up: I think an idea of ancient Dwarves being dragons or whatever the hell Old Gods are an idea worth looking into. Old Gods are stuck in stone, sing a song, and communicated with Tevinter mages only. I wonder if it would be possible to make a theory out of taint being something that came from Titans after Elves ruined them.

Edit 2: Did an oopsie, I meant Alamarri, not Avvar. Stupid me.