Following the Didact’s self-imposed exile one thousand years prior after losing the political battle over the Forerunner defense plan against the Flood, the Didact is resurrected from his cryptum on Erde-Tyrene by Forerunner Manipular Bornstellar Makes Eternal Lasting, and humans Chakas and Riser. After many days of returning to full strength, the Didact enlists the help of Bornstellar and the humans who all travel to Charum Hakkor to investigate the current state of the galaxy. There they discover that the entire system has been devastated and the Primordial has been released.
Realizing the threat that the Primordial could be to the Forerunners and not knowing the state of the Forerunner-Flood War, the Didact performs a brevit mutation on Bornstellar, turning him into a near mirror copy of the Didact. The two would later become known as the Ur-Didact (original) and IsoDidact (Bornstellar).