Following the destruction of Hala, the Asgard attempted to rebuild their civilization beyond the Milky Way Galaxy on the new homeworld of Orilla, and the forested world became home to an advanced Asgard colony. The planet was rich in neutronium, an element essential to both Asgard technology and to the creation of human-form Replicators. When Fifth brought his Replicator ship to Orilla seeking the vital element, his ship was fired upon and destroyed by the Asgard fleet under Commander Aegir. However, Fifth survived, and debris from the ship rained down upon Orilla and began to replicate and infest the city. Evacuation of the entire population was impossible, and the Asgard civilization faced annihilation until O'Neill and Thor were able to create a disruptor, a weapon effective against the Replicator invasion. Many Replicators were destroyed, others escaped with Fifth, but Orilla was spared.
Orilla was the last chance of rebuilding the Asgard empire, however the Asgard faced extinction when the physiological degeneration of the cloned race left each of them with a rapidly progressing disease. It was the decision of the High Council that the race would be extinguished before the degeneration had gone too far, and they installed all of their knowledge and most current technology aboard the Odyssey, which would become their final legacy. As Ori warships appeared above Orilla, the Asgard made the deliberate decision to end their civilization. In a massive planetary explosion, Orilla disintegrated, and the Asgard race was gone.
Cross Reference: Aegir, Asgard, Asgard High Council, Disruptor, Fifth, Hala, The Daniel Jackson, Neutronium, Odyssey, Othala, Penegal, Replicators, Thor
Episode Reference: New Order, Unending