The Infinite Cycle

The Infinite Cycle was the great pattern of renewal by which the xel'naga perpetuated their kind. Long-lived but not immortal, the xel'naga seeded the universe with life and then waited across the ages for two species, one of purity of form and one of purity of essence, to merge naturally and inherit their power. The elders would give up their essence to these new hosts, who would ascend as the next generation of xel'naga and begin the cycle anew. It was this eternal design, and one being's refusal to submit to it, that lay at the root of the wars of the Koprulu sector.

The pattern of renewal#

The xel'naga regularly seeded the universe with life as part of the Infinite Cycle. Over many generations, two species, one with purity of form and great psionic potential and another with purity of essence and a great capacity for change, would come together. Their xel'naga progenitors would then transfer their essence to the merged race, and from this union a new generation of xel'naga would arise. The xel'naga seeded life from the temple of Ulnar, as they had in countless other universes, and they observed the growth of these races without ever interfering. To guide the chosen races back to them when the time was right, the xel'naga left behind the Keystone, which would release its stored energy to awaken the slumbering elders so that they might give their lives to the new hosts. Pure of form and pure of essence would be reborn as xel'naga, the shepherds of the next turning of the cycle.

Amon's betrayal#

Amon was once a member of a species that possessed purity of essence, form, or both, and through the Infinite Cycle he was imparted with the essence of the xel'naga elders and ascended to become one of them. Only afterward did he learn what it meant to be xel'naga: that he too would one day be sacrificed to ascend the next generation, and that he could not interfere in the development of the lesser races he was to cultivate. Believing he had been deceived, Amon came to resent being torn from his previous life and refused to play his part. With a faction of like-minded xel'naga, he sought instead to raise a perfect species that would destroy the cycle, and discovered on Aiur a race of hunters with psionic powers, the future protoss, whom he judged to possess purity of form.

The perversion of the cycle#

Contrary to the xel'naga's intent, Amon and his followers personally took a hand in uplifting both the protoss and the zerg, meaning to merge them into the hybrid, a creation that was a perversion of the Infinite Cycle rather than its fulfillment. The protoss rebelled against their masters, and the creation of the Khala awakened the xel'naga in Ulnar, who fought Amon and pushed him back into the Void at terrible cost. Amon and his xel'naga were defeated and banished, though his servant Samir Duran survived to carry on his work toward the hybrid and his master's return.

The truth revealed#

The full nature of the cycle remained hidden until the End War, when Hierarch Artanis and Sarah Kerrigan descended into Ulnar together. From the temple's shrines they learned that the xel'naga had been born in the Void, that their purpose was to cultivate life and perpetuate the Infinite Cycle, and that they had never interfered in the races they seeded. The revelation forced Artanis to confront a devastating truth: if the xel'naga had not uplifted his people, then it was Amon who had, and his people's entire conception of their own history was false. When Kerrigan finally faced Amon in the Void, he told her she was nothing but a pawn in the xel'naga's design. She answered that she cared nothing for the Infinite Cycle, that she chose freedom for all life in her universe, and destroyed him.