The First Wraith-Asuran War was a conflict that was fought between the Wraith and the Asurans following the Wraith's defeat of the Ancients. During the war, Guide fought against Asurans in the hope of finding a way to stop the Asurans from eradicating the Wraith. Guide is eventually able to disable to Asuran attack code and end the war. (SGA: "Consort")
Beginnings
For 100 years the Lanteans warred continuously with the Wraith over control of the Pegasus Galaxy. The Lanteans initially held the upper hand in the war due to their vastly superior technology but in due time the conflict became a war of attrition, a situation which favoured the Wraith instead; their capture of a number of ZPMs allowed them to build huge cloning facilities to train fresh armies in record time and grow Hive Ships, Cruisers and Darts at a vastly accelerated rate. Desperate for solutions, the Lanteans tried many experiments, one of which was the creation of the nano-molecular machines which would in time give rise to the Asuran human-form Replicators. The experiment unfortunately ended in failure and the Lanteans destroyed most of the nanites, though a few survived.
No matter how many battles the Lanteans won, the Wraith just kept coming in floods regardless of their battlefield losses. Eventually the Lanteans were driven all the way back to their capital Atlantis on their homeworld Lantea. After a lengthy siege of the city by the Wraith, the Lanteans could take no more, sunk the city to the bottom of the ocean and fled through the Stargate to the Milky Way Galaxy, leaving the Pegasus Galaxy to the Wraith.
The Second Birth of the Asurans
The Wraith victory was to be short-lived however. Despite the Lantean efforts, a few nanites survived the purge on the planet Asuras and began replicating until they had regained their former strength and then some. The Asurans then concentrated on building a new hyper-metropolis on Asuras which included multiple city-ships and was powered by hundreds of ZPMs. When this was completed, the Asurans searched for their creators to show off their success but found instead their creators' domain was in ruins and a galaxy controlled by the Wraith, the very foe for which the Lanteans had created the Asurans to fight. Fueled by a rage and ferocity greater than even that of the Wraith, the Asurans immediately set about building up their military forces and soon struck out to attack the Wraith on a galaxy-wide front.
The War
The initial Asuran attack caught the Wraith completely by surprise; at first they believed it was the Lanteans resurgent due to the many similarities but they soon caught on to the true nature of their new foe. Nevertheless, in their arrogance, the Wraith believed that they could once again utilize their superior numbers to achieve victory as they had against the Lanteans and attempted to do so. They marshaled billions of their kind along with hundreds of Hive Ships and thousands of Cruisers and Darts and counterattacked with typical ferocity. To their astonishment however, the Asurans easily beat off the Wraith attacks in quick succession and continued to advance in an assault that proved unyielding and far more potent than anything the Lanteans had ever thrown at them.
Once more the Wraith were technologically outmatched, only this time their advantages in numbers and quantity of production of soldiers and warships were nullified. The nanite-based Asurans could replicate and reproduce their armies many times faster than the Wraith could clone their soldiers and they could easily construct their battleships and replace those lost far faster than the Wraith could grow and replace theirs. Moreover, as the Wraith soon discovered, the Asurans were robots and thus were immune to Wraith feeding, were physically and mentally superior beings, were unaffected by the majority of Wraith technology and were not hindered or slowed by hunger, thirst, exhaustion or the need to sleep.
The war was long and exceptionally vicious, yet it was the Wraith who by far suffered the most. Where before they were undaunted by large-scale defeats, the Asurans were able to follow up immediately after inflicting them and continue their assault without pause. Their gigantic fleets of Aurora-Class Battleships and Cruisers destroyed thousands of Hive-Ships and tens of thousands of Wraith Cruisers in mere months at a time. Though hundreds of Asuran ships were destroyed along with hundreds of thousands of Asuran troops during the conflict, the Asurans never wavered and continued to smash an unstoppable path through the Wraith territories.
From their home planet of Asuras, the Asurans fanned out like a tidal wave across the galaxy, overwhelming any and all Wraith defenses they came across. Crucially, they did not discover Atlantis, believing it to have been destroyed in the previous war. The human populations of the Pegasus Galaxy were off little interest to the Asurans at the time due to their attention being focused on the Wraith and as such, no humans ever encountered the Asurans during the war. The Wraith kept up their attempts to swamp their enemy through numbers but it was useless. Equally so was their efforts to capture and board the Asuran ships. Planet by planet, system by system the Asurans decimated the Wraith fleets and armies. The Wraith, much like the Lanteans had in the previous war, tried to open negotiations with the Asurans for a ceasefire but the Asurans paid no heed to the Wraith diplomatic missions and destroyed them and their military escorts without hesitation.
After another century of fighting, the Asurans had successfully conquered the vast majority of the territories controlled by the Wraith and were on the verge of total victory as well as complete extinction of the Wraith. The massive Wraith fleets were all but gone and their armies were being slaughtered in the field by legions of Asurans. Any and all attempts by the Wraith to rebuild their battered armies and grow new ships proved fruitless. Worse still, the Asurans had systematically tracked down and destroyed all but one of the Wraith cloning facilities, taking away all the ZPMs needed to power them and depriving the Wraith of the ability to mass-produce their soldiers and ships.
Faced with almost certain defeat and extinction, the Wraith turned to one last desperate recourse proposed by one of their top scientists. A powerful computer virus was created by the scientist intended to deactivate the directive in the Asuran base-code which compelled them to attack the Wraith. The virus was uploaded into the Asuran network through a daring suicide mission into the Asuran capital city and took effect, shutting down the directive and causing the Asurans to abandon their conquests and return to their homeworld, retreating into isolationism. The Wraith were once again victorious, only at a much higher cost than ever before.
Aftermath
The Asurans were now confined to their homeworld, unable to challenge the Wraith. The Wraith had won again but had been irreversibly crippled by the conflict. Thousands of Hive-Ships, tens of thousands of cruisers and hundreds of thousands of Darts had been destroyed along with billions of Wraith of all levels. The Asurans had systematically robbed them of the ZPMs needed to power their one surviving cloning facility, forcing the Wraith to rely on traditional methods of reproduction. The once-mighty Wraith armada was reduced to a large handful of Hives and Cruisers, which was divided among the Wraith in a feudal-like fashion, resulting in the Wraith becoming their own worst enemy.