Guys, I think we've been looking at it all wrong. We thought that the Old Elven Writing codex was referring to the Dwarves as the pillars of the earth, but with what the DLC told us, I think that's just wrong.
The Titans are the pillars of the earth, and the Dwarves are the workers who 'scurry, witless, soulless.'
What if the ancient Elves saw the Titans as a threat and waged a bloody campaign against them? The last time a Titan awoke was just before the fall of Arlathan. What if something happened that prompted a Titan to be corrupted, explaining Red Lyrium, and cut off the PT Dwarves? What if something happened that caused this corrupted Titan to churn out the first Genlocks, beings in the image of Dwarves, if it's true that the Dwarves are the Children of the Stone? For we have now learned that Titans are the Stone.
Perhaps the Titans are the Forgotten Ones, but if so, how did these beings come to be considered deities of plague, pestilence, famine, strife, and all the negative aspects? Especially when what they do doesn't seem that way? Wouldn't Malvernis be a better fit for one of the Forgotten Ones, being something that preyed upon the Dwarves and whose corruption was so potent he had to be locked away, for he ate all that was in his path?
The Darkspawn evidently hold a great deal of reverence and fear for the Primeval Thaig and the Forgotten Caverns/Bastion of the Pure/Wellspring. They don't dare tread on those grounds, but why? Why are these areas so immaculate, kept free of the Darkspawn taint?
Dagna was able to connect with the Titan, briefly, when she stared into a lyrium rune. Lyrium is the blood of the Titan, so it makes sense. She says that she felt like she was as tall as a mountain and that she was the mountain. Further, she was able to see the history of the Dwarves, something the Titan is intimately connected to.
Lyrium renders a Mage Tranquil by severing their connection to the Fade, but allows them to tap into an artistry that the Dwarves are able to do. So what is the connection? Do the Titans have some sort of effect on the Fade? The Breach did disrupt and terrify this particular Titan.
It's pointed out that no Titan would dare call to the Darkspawn, but the Darkspawn might still be able to tap into the song and hear it nonetheless. We know that lyrium sings, and red lyrium as well. The Darkspawn are drawn to a song, and with the notion that Red Lyrium is tainted, indicates that there is a blighted Titan somewhere out there. Perhaps the Old Gods sing a song that is akin to that of the Titans' song, or perhaps it's not truly the Old Gods singing at all but rather the Blighted Titan, directing its children towards the Old Gods? If so, would this account for why the Titans are the Forgotten Ones?
Andruil once ventured into the Void, a name that has been used many times in DA (most prominently to refer to the dark pits in the Fade) and forged an armor made from it, such that plague spread throughout her lands and her mental health suffered. But Mythal intervened and saved her. Would then this armor and power that stems from the Void not come from the Blight? The idea is pretty clear in that regard. If a Blighted Titan was at the heart of it all, perhaps that would explain why they were viewed as dangerous and needing to die. Perhaps after Andruil's encounter, some of the gods' followers felt it would be necessary to destroy the Dwarves and the Titans, for the world would die with them there.
And perhaps this helps explain the Civil War of the Elvhen Empire. Perhaps you had a group of Elven gods who did not want to wage war upon the Dwarves that they'd been historically trading with simply for what happened, when they might not know enough. And perhaps you had another group who were warmongers, and eventually this led to two main factions developing. This war would bring about the eventual collapse of Elvhenan and lead to Fen'Harel sealing away the Titans and the Elven Pantheon, believing that they needed to be kept safe from both themselves and their followers, along with feeling like there was too much wrong with the societies of the time that perhaps them being sealed away might be better.
This would also explain why a Titan has come about for the first time in millenia (remember, the last time one came around was near the fall of Elvhenan). The Breach disrupted the Veil that Solas created to such degree that one was able to awaken, but was so distraught by everything that it couldn't help but lash out.
And we have to account for a lot of other dialogue as well, from Cole or Solas or other people:
"You're quiet, but the old song still echoes inside, almost like Templars."
The Stone Sense is still within Varric despite how he's lived on the surface. All Dwarves can tap into it, but it becomes muted the further they are from the Stone, yet it lingers. Any Dwarf has it, for they're all Children of the Stone.
It seems that the Dwarves also had a proper connection with lyrium that allowed them some sort of magic, along with the earthshaker weapons that can both build up and demolish stone segments. This explains how the Primeval Thaig was perhaps built, and possibly even how the Rock Wraiths can be possessed by Demons -- as they end up being called Rock Wraith Abomination, and Abominations are only the result of Mages being possessed -- given that the Rock Wraiths utilize magic.
Further, we must consider the Anvil of the Void. As I've said countless times before, the workings that went into it are too unique for it to be made by one Dwarf. Lyrium is wound through it, intricately, and where else do we hear something along those lines? With the Sha-Brytol, who are fused with their armor.
The PT codex comes from a report that was sealed in the Orzammar archives by decree of one of their kings (Geldinblade). Given the logistics, it's impossible that any Dwarf scavenger could've gone from Orzammar to Kirkwall and back again, so this indicates that a PT rests somewhere around the Orzammar vicinity, which would explain the Anvil's history. Indeed, it's peculiar that no Golem is able to touch the Anvil (even though BW ended up breaking that by having Caridin forge the crown on it).
The Anvil has Spirit Forges within, that churn out those souls that were used in a Golem's creation. Perhaps they are the souls of fallen Golems rather then those of Golems themselves. We see the souls of the fallen or spectral memory imprints often in DAO, from our time exploring fallen Thaigs were the souls of dead Dwarves fight us -- perhaps they were unworthy of returning to the Stone? And their anger and bitterness has rendered them insane? -- while Kal-Hirol's ghosts lingered to show us the events of the battle. The Stone wanted those memories to survive, to be witnessed. The Titans wished for it to be seen.
Golems exist in the Primeval Thaig, suggesting that they are a relic from those days. If Red Lyrium is able to bypass the soul aspect to create golems -- as we see in the final battle with Meredith -- what does that mean for the Golems themselves? Is it a form the PT Dwarves considered sacred, a Dwarf bound in Stone and Lyrium and connected to the Titan for all of their days? Was it a form of service or servitude (for one must remember that upon awakening, Corypheus asks if we're "slaves then, to the Dwarves").
Interestingly, both Rock Wraiths and the Sha-Brytol sustain themselves on lyrium. But what marks the difference between the two? Do the Dwarves who eat lyrium and only lyrium die, but eventually become Rock Wraiths? Why are the Sha-Brytol and Rock Wraiths so different? One was met by the Legion close to Heidrun Thaig, but truly.... it confuses me.
Sorry, this is getting away from me. One moment I'm talking about a war that may or may not have happened between Elves and Dwarves, the next I'm delving too far into Dwarven history and lore. I'm like Dagna I guess.