So I posted this on GameFAQs, but I’m gonna crosspost it here just because I think dopers might be able to make a more engaging lore conversation:
I was replaying and came across the lyrium codex, I probably just shrugged this off the first playthrough but this is a lot more meaningful now:
[QUOTE=Codex: Lyrium]
When mixed into liquid and ingested, lyrium allows mages to enter the Fade when fully aware, unlike all others who reach it only when dreaming.
[/quote]
Okay, so mages can get into the fade using lyrium. Big whoop, everybody knows that.
[QUOTE=Codex: Lyrium]
Such potions can also be used to aid in the casting of especially taxing spells, for a short time granting a mage far greater power than he normally wields.
[/quote]
No really? Okay, these actually tie in to what I want to say, hence my posting the obvious stuff. It mostly comes down to this quote:
[QUOTE=Codex: Lyrium]
Mages have additionally been known to suffer physical mutation: The magister lords of the Tevinter Imperium were widely reputed to have been so affected by their years of lyrium use that they could not be recognized by their own kin, nor even as creatures that had once been human.
[/quote]
Now I admit, outright, that this could easily just be a thinly veiled reference to abominations, but I want to present a different angle.
We know the Black City is in the fade, what gets you into the fade? Lyrium. In addition, using large amounts of Lyrium also increases your power immensely. Further, we know that the Black City is almost unreachable in the fade, so it would at the very least require a large amount of power and effort to get there; power that could, in theory, be granted by large amounts of lyrium. If an over-abundance of lyrium in the system can cause long-term mutations, I think it’s very possible that perhaps the Tevinter Imperium tried to get to the Black City, used too much lyrium to get there, and ended up mutating themselves into Darkspawn.
This has other implications, for instance, the reason they’re so drawn to the Deep Roads could be due to the fact that Lyrium tends to be there and they’re principally fueled by their addiction. It also seems that perhaps instead of seeking Old Gods, the Archdaemon transformation could be facilitated by a Darkspawn consuming an immense dose of lyrium. However, I don’t have enough evidence to forego the Old God idea as stated in the game, especially since then I’d have to make up an explanation for the Morrigan Baby ritual and the Archdaemon body swap on death.
There’s still a lot of little holes, such as why if it’s simply lyrium corruption why they’re not all powerful mages, why the taint seems to spread like a virus, and why they don’t seem autonomous. At the very least it doesn’t describe the Golden City/Black City change, but that one can be easily dealt with since the game sort of hand-waves their own explanation anyway. The others, I suspect, can be dealt with by things like withdrawl, blood concentration of lyrium, and being driven by addiction. The real answer is, I don’t have any hard proof for these facets, but I think the theory still has at least some solid grounding.