That sucks cause a lot of Inquisition's storylines and factions are directly based on DA2. It's like being told to play ME3's Rannoch campaign but not having any knowledges of Quarian and Geth history prior to that point.

I can try though.

Between the events of Origins and Inquisition:

-4 years prior to the start of Inquisition, Hawke, the Champion of Kirkwall, participated in the Kirkwall Mage Rebellion, in response to both the destruction of the City State's Chantry and years of corrupt abuse from the Templar Order.

-Southern Thedas's Mage Circles disbanded, after overwhelming abuse from the Templars

-Mages were fighting amongst themselves, as well as warring with the Templars, who at which point also rebelled against the Chantry.

-The scars of the Fifth Blight remain in Ferelden still, and a Civil War is consuming the neighboring nation of Orlais.

-The Darkpawn remain, but in the form of small groups travelers might occasionally war with, rather than an organized, marauding force they were in Origins.

-Dragons are common, as nearly all Dragons aren't Old Gods (the antagonists of Origins), and don't have any ties to the Blight like the Big Bad of Origins did.