"On a distant, shadowed world, the protoss will make their final stand. Their heroes will gather, their forces will be marshaled, and they will die bravely. But still, they will die. And my zerg... will be slaves... to the hybrid. All will bow before the power... of the Fallen One."
The prophecy came into being after Amon's war with the xel'naga, with the greater bulk of their species being consumed by the zerg, while the survivors returned to Ulnar. The xel'naga Ouros created the prophecy in order to guide the future races that possessed purity of form and essence to Ulnar where they would awaken the last of the xel'naga. The prophecy was stored in fragments on Ulaan.
At the end of the Brood War, Zeratul discovered the hybrids on a dark moon. This prompted a search for more information after the war; in 2503, he arrived on a world via a wormhole created by energy creatures that put him on the path to finding the prophecy. He believed (at least partially correctly) that a benevolent force had created it in order to assist the protoss (or perhaps, a multitude of races) in a time of great need.
Zeratul found rumors of the prophecy on Ulaan which he believed foretold the return of the xel'naga. The prelate traveled to the world on the eve of the Second Great War and, despite competition from the Queen of Blades, retrieved the fragments and brought them to the forbidden archive world of Zhakul where they could be interpreted by preservers.
The preservers deciphered the fragments and prompted Zeratul to seek further information from the dead Overmind. With the help of Tassadar's spirit, the dark templar gained access to the creature's vision of the future. Zeratul learned that Kerrigan was essential to stopping Amon and his apocalyptic plans for the future.
Zeratul recorded what he had learned through the prophecy into an ihan crystal. He gave the crystal to Jim Raynor during the Second Great War to ensure Kerrigan's survival. Raynor believed the prelate had delivered the information at some risk to himself.[note 1]
Valerian Mengsk also became aware of the prophecy. When he revealed this knowledge, Raynor was surprised.
When disinfected Kerrigan, Zeratul approached her leviathan and confronted her. Kerrigan asked his reason for being here and Zeratul showed her Zerus, the birthplace of the zerg. Zeratul also added that he had to regain his power as Queen of Blades and so continue the prophecy. Kerrigan acceded, but she said would to have revenge by Arcturus Mengsk and not by the prophecy.
With the death of Arcturus Mengsk, Kerrigan took her Swarm to confront Amon.
Before the End War, Zeratul sought the last part of the prophecy that would give them the edge over Amon. He entered a Moebius Foundation facility searching for information on the world where Amon had been reborn. Arriving at the site, Zeratul discovered that Moebius Corps forces were slaves of the hybrid and the terrans had experimented with Protoss technology and several Templar. Zeratul, with PraetorTalis rescued the Templar and managed to locate where Amon was reborn: Atrias.
Zeratul and Talis went to Atrias and fought against Tal'darim under the command of HighlordMa'lash. Talis´s forces allowed Zeratul to enter the Temple of Erris. Inside the temple, Ouros (once more disguised as Tassadar) reappeared in the Void catalyst where Ma'lash communicated with Amon. Tassadar told Zeratul that the Keystone would usher them unto hope, and showed him its location on Korhal. Despite Amon's efforts, Zeratul made it out alive, and with the prophecy complete, departed to find and warn HierarchArtanis of the looming threat.