Spoilers to anyone who hasn't finished the DLC
I played through the DLC and unlike some I utterly love it I'm always a **** for lore as such I present a few theories:
The Sha-Brytol are ever living dwarves, bound into their armour with lyrium. Not dissimilar from a golem. What if Caradin had not discovered how to make golems but rediscovered how to make a revered defender? Consider also the Sha-Brytol's slavish obedience to the titan perhaps a golem control rod uses the same sort of effect.
When we were at the wayspring we were actually in the 'Fade' or not exactly the fade but an area where the veil separating the fade and the real world never formed. I say this because...well look at the place. There were clouds and a light like the miday sun coming from nowhere, giant stalagmites and stalactites jutted from the floor and the ceiling, and before that a glowing, singing valley of vein-shaped Lyrium, clearly these are not areas that behave like the majority of the natural world. A Titan then is not so much a lifeform as we know it so much as a sentient location. Perhaps that is why Valta was able to harness magic, she was struck with lyrium in a spot where the fade and the real world intersected which leads me to my next theory.
In the Arbor Wilds Morrigan will talk to you about a time where beings of great power walked the earth, According to one of the comics Qunari myth tells of a time when the fade intersected, they believe this is where the Old Gods of Tevinter came from. Long ago Titans roamed the surface fusing the the real world and the fade as one to increase their power, to reproduce or simply because it's what a Titan does. I believe that during this time Humans Elves and Qunari where exposed to Lyrium just like Valta whilst the majority of dwarves hid deep underground (hence their hatered and mistrust of the surfacers). Perhaps they always lived like that, perhaps this is where the deep roads came from, a series of bunkers built to survive a disaster that lasted for so long that the dwarves began to forget they lived anywhere else.
I noticed that in Crestwood there were veilfire sconces on the walls, at the time I thought perhaps the old dwarves simply hired mages for whatever reason but now I wonder....the Crestwood ruins don't seem to be an actual Thaig (they're never named as one anyway) and they're unusually close to the surface, perhaps the Crestwood Dwarves were touched by the Titans and became the Forerunners of the Sha Brytol and their mages worked with something akin to veilfire. After all the runes there still sing.....
Eventually the Titans were defeated, and I believe that defeat involved the Dwarves of the primeval Thaig and Red Lyrium is a rampant WMD meant to poison the 'blood' of the titans.With most of the Titans dead the Sha-Brytol fought their own brothers through the newly constructed deep roads and down to the depths of the earth and took the last of the Titans with them, hence their hatred of mainstream dwarves--as far as they're concerned the Thaig-Dwarves killed their gods.
Retour en haut
Maybe Sandal just wandered too far from the Sha-Brytol when he was a kid. Would explain a lot.
(Dagna is going to try to rip open the Deep Roads if she ever finds out.)
So far we've gotten lorebombs for elves, humans, and dwarves... Only Qunari left to go. (Maybe Koslun will time travel and tell them how much they messed up what he was trying to teach them. 
