Xel'Naga
The Xel'Naga are a race known for their appearance in the Starcraft video game. They are described as an ancient race and the most powerful species known in the universe, the creator race of the Zerg and the Protoss in the StarCraft universe. His whereabouts are currently unknown. Players who fully appreciated the game's story infer from in-game dialogue that a Xel'Naga (possibly the last) could become Amon.
History
The Xel'naga arrived in the Milky Way millions of years before The Great War. They sowed many seeds on different worlds within their domain. The goal of this was to find the candidate that contains the Purity of Form and the one that has the Purity of Essence.
During their travels they learned of The Voice in the Dark, an evil entity from the void that consumed entire civilizations. As the Xel'Naga valued life, they encased him in an Argus crystal.
The Creation of the Protoss
The Xel'Naga were obsessed with creating a perfect race and for this they directed all their efforts to achieve 'purity of form'. Creatures from a distant tropical planet called Aiur were chosen by the Xel'Naga to guide their evolution. This is how the Protoss were born, which means the first to be born, who possessed great adaptability in the face of adverse natural conditions and who possessed the ability to communicate through telepathy. The Protoss lived for hundreds of generations in peace and harmony, unaware that the Xel'Naga guided their steps. When the Protoss became aware of the universe and had advanced technology, the Xel'Naga made themselves known. The Xel'Naga were soon envied by the Protoss. The fights between tribes to get to possess the most advanced technologies ended up causing numerous casualties among the Xel'Naga, who years before had been the object of reverence for the Protoss. The Xel'Naga fled the Aiur in outrage and went to do their next great work: the Zerg.
The Creation of the Zerg
The Xel'Naga made one last effort to create the perfect race but this time they would put their efforts into achieving a 'purity of essence'. They traveled the universe until they reached the planet Zerus, a volcanic world where life was very difficult. They found some very interesting parasites there. They mutated and genetically modified their DNA taking control of other living beings that were above the evolutionary chain, focusing on the most powerful species to assimilate their strengths while the weaker species were exterminated to keep theirs even purer.
The parasites were called Zerg. The Xel'Naga found that their new race not only controlled other creatures, but also mutated them, making shells, spikes, claws, and other defensive and offensive material appear on them. The Xel'Naga gave the Zerg a common mind, the Overmind, a creature that combined in a single being all the thoughts of the Zerg, thus the Xel'Naga made sure that there were no thoughts of their own to stop them. the development of the entire species, which had been his mistake with the Protoss; but, this type of domain would also bring them serious problems.
The disappearance of the Xel'Naga
The Zerg Overmind organized their swarm into castes based on the strength of the parasitized creatures thus creating the concept of the Hive. Commanding the Zerg armies were the Cerebrates. Thousands of years had already passed when the Supermind discovered the presence of its creators. The Supermind's sole objective was the development of her species to perfection, which is why she decided to incorporate the Xel'Naga into her gene base. The Overmind managed to neutralize the link with the Xel'Naga in a certain way, so they were unaware before their attack, lost numerous motherships and were eradicated from Zerus, although some may have survived the Zerg onslaught, since the Xel's #39;Naga of Zerus did not make up the entirety of the race.
In-game references
'The Xel'Naga created both the Protoss and the Zerg, Commander. They were gods in their time." - Dr Emil Narud.
"The temple of the Xel'Naga will channel the two crystals." - Matriaca of the Protoss Raszagal.