The Eternals are an evolutionary offshoot of humanity living on Earth who possess greater powers and longer lifespans than the mainstream human race. The Eternals first came into being about a million years ago when the extraterrestrial Celestials arrived on Earth to perform genetic experiments on the nascent human race. To test the adaptability of the human gene, the Celestials accelerated the evolution of a handful of subjects and gave them the genetic potential to mentally manipulate limited quantities of cosmic energy, as well as other superhuman traits. Thus the Celestials created the race of Eternals. The Celestials also performed experiments on Earth that led to the creation of the Deviants, and to the implantation of latent genetic material in other specimens of humanity's ancestors that would one day permit benevolent mutations in human beings.
At first the Eternals' genetic potential for extraordinarily long lifespans and virtual invulnerability lay dormant. A devastating civil war eventually broke out among the first known generation of Eternals. The two opposing factions, one led by Kronos (whose name is also spelled "Chronos") and one by his brother Uranos, clashed in a conflict of ideologies over their people's destiny. Chronos's side prevailed, and the warlike Uranos and his surviving band of followers were exiled into outer space. The exiles found a supply depot left by the alien Kree on the planet now known as Uranus, and used it to construct a spaceship in which they attempted to return to Earth and renew their war with their brethren. Four Eternals stayed on Uranus and gave rise to a small colony of Uranian Eternals, which, however, was wiped out in the twentieth century. The rest of Uranos's followers were attacked by a Knee armada before reaching Earth. The survivors among Uranos's band built a civilization on Saturn's moon Titan. One of Uranos's followers, Aflok, was taken by the Kree for vivisection. Learning that the being had derived from Earth, the Kree determined to perform genetic experiments on Earth's pre-humans themselves. Their experiments would result in the Inhumans.
Kronos was working in his laboratory in the Earth Eternals' city of Titanos on an experiment with cosmic energy when he accidentally caused an explosion that demolished Titanos and subjected the Eternals to a cosmic particle bombardment. This irradiation activated the latent genes in the Eternals that gave them their long lifespans and virtual invulnerability, and enabled them to pass these active genes down to the children produced by any mated couple of Earth Eternals. (There is as yet no known example of an Eternal and a human mate together producing a child with Eternal superhuman traits.) Kronos's atoms were scattered, but his astral form still survives on this plane of reality.
After Kronos's physical death, his eldest sons, Zuras and Alars, initiated the first creation of the Uni-Mind, a collective melding of the minds and bodies of the Eternals. While in the form of the Uni-Mind, the Eternals determined that Zuras should be Kronos's successor as their leader. To avoid disunity among the Eternals, Alars, who differed with Zuras as to what the Eternals' goals should be, left for outer space. Eventually, Alars arrived on Titan, where he mated with Sui-San, the last survivor of a civil war among the Eternals there. Together Alars and Sui-San repopulated Titan. However, since Sui-San was not affected by Krones's cosmic energy, their children were stronger and longer-lived than the Eternals previously living on Titan, but not as powerful or long-lived as the Eternals of Earth. Alars renamed himself Mentor, and the race of Titanian Eternals, although recently greatly reduced in number, still exists today.
Zuras directed the construction of the principal city of the Eternals, Olympia, in a mountainous region in Greece. Two other major Eternal cities were founded: Polaria in Siberia and Oceana in the Pacific. Many Eternals have lived among ordinary human beings over the centuries.
Olympia lay near the principal nexus between Earth's dimension and that of the Olympian gods on Mount Olympus. Zuras and Zeus, leader of the Olympian gods, made a mutual non-interference pact between their two races. The people of ancient Greece and Roma often confused the Olympian Eternals with the Olympian gods. Over the centuries the Eternals have continually fought the Deviants' attempts to gain power.
In recent years the Fourth Host of the Celestials arrived on Earth to judge humanity. Fearing that the Celestials would destroy Earth if they judged against its people, Zuras led the Eternals against the Celestials, who retaliated by killing him. The Celestials judged in Earth's favor and left Earth.
Zuras's daughter Thena contacted Zuras's spirit before it left this plane reality, and thus learned that the Eternals were to leave Earth to explore space now that the Celestials had departed. Virtually all of Earth's Eternals left for space in the form of the Uni-Mind. However, the Eternals' collective consciousness in the Uni-Mind decreed, that a small number of Eternals who were particularly involved in Earthly matters remain behind. Among the Eternals known to still live on Earth are Thena, their new ruler, Ikaris, Sarsi, Makkari; the Forgotten One, Kingo Sunen, Sprite, Cybele, Phastos, Khoryphca, and Interloper.
The life force of all the Eternal of Earth is augmented by cosmic energy. Moreover, each of the Eternals of Earth maintains a virtually unbreakable mental control over the processes and structure of his or her body, even when he or she is asleep or unconscious. As a result, the Eternals of Earth have lifespans that last thousands of years, are immune to disease and aging, are virtually indestructible, and, if somehow injured, can regenerate injured or missing organic tissue. There are only two known means by which Earth Eternals can die. One is through an injury that disperses a significant portion of the Eternal's body molecules; the other involves overwhelming and breaking the Eternal's mental hold over his or her own body. Once this hold is broken, then the Eternal can be injured or killed through conventional means. An Eternal's control over his or her body allows him or her to appear at whatever age he or she wishes. Hence, although many known Eternals have lived for at least several thousand years, they appear to be in their twenties. Cosmic energy bolsters the metabolism of Eternals so they do not tire from physical exertion. Through mental concentration they can resist temperature extremes.
Eternals are born with the potential for various superhuman abilities. Although an Eternal may be born with less potential for one ability than another, he or she can overcome that difference through training, Eternals develop their superhuman abilities through training and discipline over their long lives. Each Eternal is guided by personal desires in deciding how far to develop a specific ability. Sersi, for example, is acknowledged to have developed her talent for matter rearrangement far more than any other known Eternal has.
All Eternals have superhuman strength, and an average Eternal can lift (press) about 15 tons without using his or her mental powers to negate the force of gravity on whatever he or she is lifting.
Eternals can levitate themselves by mentally manipulating gravitons (subatomic particles carrying the force of gravitational attraction between atoms) around them. An Eternal can also levitate other persons or objects while simultaneously levitating himself or herself. Eternals can "fly" at great speed through levitation, and the average Eternal can thus travel at 600 miles per hour.
Eternals can mentally create illusions so as to disguise themselves. They can also psionically manipulate atoms and molecules so as to transform an object's shape. However, this ability is highly limited in most Eternals,
Eternals can project cosmic energy in the form of beams from their eyes or beams or flashes from their hands. This cosmic energy, stored n specialized enclaves of cells in their bodies, can be used as force, heat, light, and possibly other forms of electromagnetic energy. An average Eternal can project a maximum concussive force of at least 200 pounds per square inch and heat reaching a maximum temperature of 2000° Fahrenheit, The maximum effective range for an average Eternal's energy beams seems to be about 176 feet, The expenditure of cosmic energy in this way continually for several hours will temporally deplete an Eternal's physical strength, but not his or her resistance to injury, although it will temporarily increase his or her sensitivity to pain. However, the Eternal will rapidly return to normal after such lengthy energy expenditure is over.
Several Eternals are also known to be able to teleport themselves psionically.
The Eternals have an extremely low birthrate among themselves, having one child every millennium or so. However, those Eternals who choose to mate with ordinary human beings often have children much more frequently, although these Children will not themselves be Eternals. Hence, the population level of the Eternals has remained very stable over thousands of years.