A Blight is distinct from the occasional darkspawn raids, in which the darkspawn are few, scattered, and disorganized, plaguing the Deep Roads almost exclusively. These grand highway-tunnels – constructed by the dwarves at the height of their empire but almost entirely controlled by darkspawn ever since the First Blight – extend throughout subterranean Thedas.
When the darkspawn discover one of the Old Gods—ancient draconic creatures slumbering in the depths of the earth—they infect it with their taint, and it rises as an Archdemon. Unified by its will, the darkspawn surge to the surface and spread across the lands, warping and destroying all in their path. Victims not killed are dragged underground to be eaten or turned into Broodmothers, water sources are defiled, crops and animals plagued. The sky fills with black clouds that block out the sun, making it easier for more darkspawn to surface.
The only way to end a Blight is to slay its Archdemon, and the only ones who have ever managed such a feat have been Grey Wardens. For this reason, the order accords legendary respect throughout most nations (though their presence in Ferelden in the decades prior to the events of Origins is weakened by local political struggles and the centuries that have elapsed since the most recent Blight).
The Blight Disease
A blight wolf The corruption (or “taint”) spread by the darkspawn twists and corrupts all living organisms, which go mad, develop physical afflictions, and/or perish outright. Survivors are transformed into ghouls (animal equivalents include bereskarn, blight wolves and corrupted spiders). In rare cases an infected subject (e.g. The Mabari Hound) may make a full recovery if given early care; however, most are put down to prevent them from transforming and/or spreading the disease further – or to spare them a slower and/or uglier impending death.
Even “ghouled” victims will ultimately be killed by the disease, leaving whole areas completely lifeless. The longer an infected creature ‘lives’, the more it will manifest hair loss, aggressive or even rabid behaviour, and numerous deformities, protrusions, boils and sores.
The Thaw begins after the Archdemon is defeated, as surviving darkspawn flee back towards the Deep Roads and the periphery of blighted lands can begin to be reclaimed. Surviving Grey Wardens strive to catch stragglers before they go to ground – referring to this as the Thaw Hunt.
The History of Blights in Thedas
The Chantry teaches that it is the hubris of men that brought the darkspawn into existence. The mage rulers of the Tevinter Imperium sought to usurp the Golden City — the afterlife created by the Maker for mortals — but were cast out, twisted with corruption, and returned as monsters – the first darkspawn. The dwarves are less inclined to believe such a history; to them, the darkspawn simply appeared one day and have been their bitter enemies ever since. (Some dwarves do suggest that the humans are the reason for their existence, though not necessarily magisters specifically.)
The First Blight
After the corruption of the magisters, the first darkspawn awaken Dumat, first among Tevinter’s Old Gods, and the first Archdemon. Thedas is nearly overrun and the dwarven race nearly extinguished (to this day only Orzammar and Kal-Sharok still stand against the darkspawn). The Grey Wardens are founded, and Dumat is finally slain at the Battle of the Silent Plains in 992 TE. The Imperium is left severely weakened, and is subsequently overthrown by a mass movement led by the prophet Andraste.
The Second Blight
Zazikel awakens in 1:5 Divine and the second Blight begins, with darkspawn coming out of the mountains in all corners of the continent. They slaughter the entire city of Nordbotten in the Anderfels before the Grey Wardens finally get the word out. The Free Marches and Orlais are hard-pressed to defend themselves, but the Wardens and the armies under Emperor Kordillus Drakon I make the difference. Just over ten years into the second Blight the Orlesians defeat several hordes of darkspawn, including the hard-fought victory at the Battle of Cumberland. As the Orlesians and Grey Wardens share continued victories, the second Blight winds down to its last battle in Starkhaven. The Wardens destroy Zazikel, and the darkspawn are routed for the second time.
The Third Blight
The Old God Toth awakens in 3:10 Towers, and the third Blight erupts in the central lands of Thedas with darkspawn coming in greater numbers than ever before. Swarms of them engulf the Tevinter cities of Marnas Pell and Vyrantium, and the Orlesian cities of Arlesans and Montsimmard. The Grey Wardens of both countries are able to quickly organize a defense, and despite heavy losses in the besieged cities the darkspawn are pushed back, proceeding to ravage what will later become Nevarra as well as the Free Marches and the length of the Minanter River. Pressure from Weisshaupt convinces Orlais and Tevinter to unite against the horde, but neither will consent to aid the beleaguered city-states. After fifteen years of conflict, the armies of Orlais and Tevinter join the Grey Wardens at Hunter Fell; Toth is destroyed, and the darkspawn in attendance are slaughtered in one of the bloodiest battles in history.
The Fourth Blight
5:12 – 24 Exalted
The fourth Blight begins when the archdemon Andoral arises just as the Chantry’s exalted march against the Tevinter Imperium ends. This time, the darkspawn appear in great numbers in the northeast and northwestern regions of Thedas. As Antiva is overrun and its ruling family wiped out, the darkspawn pour into the Free Marches and Rivain. The Blight also rises in the Anderfels once again, the capital city of Hossberg coming under siege. Orlais and Tevinter are beset by decreasing numbers and manage to drive the darkspawn back into the Deep Roads; despite these successes they send next to no aid to their devastated neighbors. In the Deep Roads, the darkspawn capture the Ortan Thaig.1
In 5:20 Exalted, the elven hero Garahel and his fellow Grey Wardens lead an army of Anders to Hossberg and break the siege. The Wardens then march to Starkhaven and form an alliance between the minor kings and teyrns of the Free Marches. Under the Grey Wardens’ banner this united army marches north, eventually freeing Antiva at the Battle of Ayesleigh. It is here the Fourth Blight ends – and Garahel dies, having cast down and slain Andoral in single combat.
So many darkspawn are slaughtered in the Fourth Blight, it is easy for some to imagine that they will never return. This notion is compounded by a growing number of rulers telling their people that the darkspawn were forever defeated as a way to restore order. The next Blight is four centuries in the future, and the fact that dwarves must continue to repel darkspawn from their borders is increasingly ignored by surfacers (excluding the Grey Wardens).