The Tevinter Imperium is the oldest nation in Thedas and holds the secrets to many of the mysteries of Dragon Age; but, because it's so old and predates many of the modern institutions in Thedas, many of its belief systems that form the foundations of its culture are based on lies that frame real events in history incorrectly to make Tevinter look more positive. In particular, their beliefs about the origins of the Blight and the Fall of the Elves are misrepresented and, if the truth about these historical events were to be revealed in Dragon Age: Dreadwolf, the consequences for Tevinter could be dire.
One of the most compelling parts of the lore in Dragon Age is that it works much the same as real world history: instead of coming from one indisputable source, events from the past are pieced together from a variety of different places and sources in order to build singular picture. Major institutions and nations in Thedas use this to pick and choose how to frame their role in history, with an example of this being the Seekers and how they covered up the fact that they used to have mages in their ranks, as revealed with Inquisitor Ameridan. In the next game in the series, more historical beliefs will surely be challenged.
Why Tevinter's Past is So Fractured
Dragon Age: Inquisition revealed several truths that shattered previously established lore, such as the cause of the Blight, the creation of the Veil, and the fall of Arlathan. Dorian, as a mage from Tevinter, provides a perspective into the possible reaction from Tevinter toward these revelations, particularly in reaction to Corypheus and the reveals from Dragon Age: Inquisition: Trespasser.
Tevinter's beliefs about the Blight are different to the story the Orlesian Chantry, which state that the First Blight began after the Magisters attempted to free the Old Gods by entering the Fade physically and entering the Golden City, turning it into the Black City and releasing the Blight. Tevinter's position is that darkspawn and the magisters aren't related and that darkspawn always existed. While it may be true that darkspawn may have existed before the Blight, the events of the Magisters physically were true, as stated by Corypheus in Dragon Age 2: Legacy and Dragon Age: Inquisition.
The Foundation of Tevinter's Culture May Be at Stake
Another belief that is proven false is the fall of Arlathan, or the elven empire. The Tevinter Imperium believe they overthrew the elves and ransacked their empire, when the reality is far more mundane: instead, Arlathan fell when the Veil was created, and Tevinter was built on the ruins of it. As a result, much of the magic in Tevinter is based on elven magic looted from the ruins of their empire, a reality that may prove detrimental in Dragon Age: Dreadwolf. It's also this belief that fuels much of the discrimination against elves in Tevinter; most elves in the Imperium are slaves, and this is justified because of Tevinter's supposed overthrow of Arlathan centuries before.
One belief where Tevinter may be proven correct is the Imperial Chantry's assertion that Andraste was a powerful mortal mage. It's this assertion that forms one of the major schisms between the Tevinter and Orlesian Chantries, as the Orlesian Chantry believes Andraste was divine and not a mage. There is evidence, however, that supports the Tevinter's claim that Andraste was a mage, but a theory that is likely to be true and would be equally detrimental to both Chantries is that Andraste was possibly a vessel for the elven god of justice, Mythal.
How Tevinter deals with these revelations is ultimately up to the citizens of the current era to decide; what to do with the information and how to move forward may be a choice left up to the player. Dorian returns to Tevinter with the intention of making it a better place, and perhaps he will play a pivotal role in how Tevinter moves forward.
Dragon Age: Dreadwolf is in development.