>>720117662
According to the Chantry, they were created when the Magisters Sidereal of the Tevinter Imperium opened a portal into the Golden City, tainting the realm of the Maker with their corruption and returning as the first darkspawn, their evil transfiguring them into the monsters they became. The taint they carried infected others, turning them into darkspawn as well.
The dwarves give little credit to Chantry beliefs, but they themselves have no known origin story for the darkspawn. As far as the dwarves are concerned, the darkspawn simply appeared underground, with some Shapers hypothesizing that there is a queen broodmother − the first mother.
According to Dorian Pavus and Fenris, magisters deny their involvement in starting the Blight. They claim the darkspawn have always existed, and that the magisters have no connection to them. Slaves are not regaled with a Tevinter version of the Chant of Light, so Fenris could not confirm if there is an official Imperial Chantry stance beyond typical Tevinter opinion.
tl;dr No. They're just "not-Orcses-from-Mordor"