The Celestials are a race of enormous, enigmatic, nigh-omnipotent armored space gods who have a long history of meddling with Earth. Created by Jack Kirby and first appearing in The Eternals #2 (1976), they were likely inspired by Erich Von Daniken’s wildly popular early ’70s book Chariots Of The Gods?, a book that proposed ancient civilizations like the Mayans were aided by aliens. Kirby ran with that idea and created a cosmic scenario so compelling that it lasted far beyond the brief initial run of the Eternals’ series.

As initially conceived, the Celestials were cosmic scientists, experimenting with the dominant species on young planets for their own mysterious ends. On each planet, they would imbue a small number with immortality and a share of their cosmic powers. They would become that planet’s Eternals. They’d take another subset and make their genetic material highly unstable, resulting in rapid mutation rates. Those would become Deviants. Finally, they subtly altered the DNA of the rest of their test subjects, who evolved to become humans.

The Celestials would return from time to time to monitor these planets, until it was judgment time. In Guardians of the Galaxy, a Celestial named Eson the Searcher can be seen wiping out a planet’s population with the aid of the Power Stone. Ego claimed to be a Celestial as well. With the introduction of the Celestials in the Eternals film, don’t be surprised to see them connected to a lot of events in the MCU.

The First Firmament

Who made the Celestials? What was their purpose? They were created by the first cosmos that existed, a sentient universe that called itself the First Firmament. It was alone and was the entirety of its universe, but it got lonely and created beings to keep it company. Paralleling the story of Lucifer to a degree, the group of celestial creatures that were loyal to it were known as Aspirants. They wore dark-colored armor and had no desires other than to praise the creations of their creator.

The other group of beings became the more familiar Celestials, and they were interested in change, growth, and the possibility of death. They wanted to test the creations of the universe in order to see what would happen. They weren’t satisfied simply praising the First Firmament’s plans and creations. This was seen as blasphemous by the First Firmament, who wanted its creations to praise it. War broke out as a result.

The Celestial War

War broke out between the Aspirants, loyal to the First Firmament, and the rebel Celestials. Both sides suffered heavy losses, but the Aspirants eventually won with Godkiller Armor, which wiped out most of the Celestials’ forces. However, after their foes were scattered, the Aspirants stripped the Godkiller Armor for parts to build new space fleets. Shortly thereafter, a civil war broke out.

The remaining Celestials attacked their divided and distracted enemies and beat them. Desperate for a decisive win, they unleashed their most destructive weapons all at once and split the First Firmament into pieces. This was the birth of the Multiverse, as the First Firmament’s discorporation created hundreds of new, divergent realities.

With no opposition, the Celestials were free to meddle with the new species evolving on millions of worlds. They created a race of servants called Omegas, who helped the Celestials’ mission. Among other things, they created super-powered beings on every Earth throughout the multiverse, so they could have a planet that would oppose the Aspirants. The Aspirants, later known as the Death Celestials, wanted nothing less than the destruction of every multiverse in the cosmos. The inhabitants of Earth, but especially the humans, had the ability to resist the Horde and the Death Celestials.

The Celestials soon set the now ever-growing multiverse into motion, with universes dying and being reborn in a never-ending cycle. What remained of the First Firmament waited through several cosmic reboots until it was ready to attack.

The Progenitor and Zgreb

The Celestials first happened upon Earth when one named the Progenitor crash-landed four billion years ago. He was infected by a powerful insectoid race known as the Horde, who are the Celestials’ opposite number. Whereas the Celestials are creators and cultivators, the Horde exists to destroy. They both serve a being called the Fulcrum. When a planet tips toward Deviant influence, the Horde receives that planet’s energy when it’s judged. If it tips toward Eternal influence, then the Celestials receive that energy. Celestials are also fair game for the Horde, which is why the Progenitor fell.

When he died, his infected essence oozed into the primordial Earth, along with thousands of Horde eggs. Loki claimed that it was the Progenitor’s essence that was responsible for the rise of superpowers amongst humanity. Loki is also a great big liar, so who knows?

What happened for sure is that another Celestial named Zgreb tracked the Progenitor down a million years ago. It got infected by the Horde and they transformed it into the first Dark Celestial. Zgreb tried to destroy the Earth, but it was opposed by the Stone Age Avengers, led by Odin. That group included ancient versions of the Phoenix, the Ghost Rider, Star Brand, the Black Panther, Iron Fist, and the Sorcerer Supreme Agamotto. They weren’t able to kill the Celestial, but they did bury it and seal it away. That lasted until Loki freed Zgreb a million years later.

The First Host

Not long after Zgreb was buried by the Stone Age Avengers, the First Celestial Host visited Earth. The planet had its attention after the loss of two Celestials, and they set about their usual course of finding the dominant species and experimenting on it. The Avengers tried to oppose them but were easily swept aside, and the host went about their business. Gammenon the Gatherer captured test subjects after Eson the Searcher found them. Oneg the Prober and Ziran the Tester determined which of their subjects would go on to become Eternals or Deviants, and which would receive a mysterious boost to their DNA that would result in more subtle mutations.

At least this was their method with regard to races like the Kree and the Skrulls. Dire Wraiths, former foes of Rom the Spaceknight, were revealed to be the Deviant strain of the Skrull race. Loki claimed that after the Celestials defeated the Avengers, they didn’t feel the need to alter humanity’s DNA, as it was already being affected by the deceased and diseased Progenitor’s body. They preferred to keep the Horde infection localized, believing that humanity had absorbed the ability to defeat the Horde into their genetic material.

The Second Host

Around 20,000 years ago, the Second Celestial Host arrived to monitor the progress of the Earth’s three dominant subspecies. The Deviants had staked out the upper hand as the Eternals were having trouble protecting humanity from them, spawning many a myth about monsters. The Deviant kingdom of Lemuria was at war with the smaller human kingdom of Atlantis when the Celestials arrived. The arrogant and overconfident Deviants made the critical error of attacking the Celestials’ ship in orbit.

The Celestials responded by blasting Lemuria so hard that it sank to the bottom of the ocean, along with Atlantis, rearranging the Earth’s landmass in the process. Eson the Searcher was the one who did most of the destructive heavy lifting. Most of the Deviant population was annihilated in what they called the Great Cataclysm and what was called the Great Flood by humans, allowing humanity to become the Earth’s dominant species.

However, by the Celestials’ own protocol, the Deviants had become the Earth’s dominant species and the Earth should have been culled right at that time, giving its energies to the Horde. The leader of the Second Host, Arishem the Judge, decided instead to destroy the Deviants when they attacked. This drew sharp disagreement from Arishem’s fellow Celestial, Tiamut the Communicator, who attacked Arishem. Tiamut was defeated by the combined Host, stripped of its soul, and buried near what is now California. Tiamut was now known as the Dreaming Celestial. This was now the third Celestial buried somewhere on Earth.

The Third Host

The Celestials popped in for the third time a thousand years ago. Odin, who had opposed them and lost millennia earlier as leader of the Stone Age Avengers, this time went around to the Sky-Fathers of the various pantheons of Earth gods to provide a united front against the Space Gods. The delegation sent against the host consisted of Odin, Zeus, and Vishnu. Yes, a deity from an actual, active religion was made part of this story.

Arishem responded simply. It showed the so-called "gods" who was boss by giving them a vision of how easily they could be cut off from Earth using the power of the Celestials. Their various pantheons relied on worship, and being cut off would have quickly wiped them all out, so Arishem made them all vow not to interfere with the Celestials’ upcoming judgment for the next thousand years.

Thor learned this the hard way when he was trying to figure out why Odin was preventing him from interfering with the Celestials, and Arishem showed him this vision.

Apocalypse

In the 11th century, the immortal mutant En Sabah Nur heard about a Mongolian ruler powered by some kind of mysterious technology. No stranger to such artifacts during his long life, he tracked down a being called Garbha-Hsien in a craft called Ship and defeated him. Nur spent years on Ship, building a Sphinx around it, before he started hearing a voice in his head. This was the voice of the Celestial Eson the Searcher, who offered him use of Ship’s technology in order to one day rule the world. Nur accepted, though he was told the Celestials would one day return to collect on their favor. Why Eson chose to do this is unclear, just like many of the Celestials’ motivations are murky at best.

Nur started calling himself Apocalypse as he and his forces were plagued by a barbarian with a cybernetic arm called the Traveller. This was Nathan "Cable" Summers, traveling back in time to engage his ancient enemy. Through a series of accidents involving his own techno-virus infused blood, Apocalypse learned how to understand Ship, which was a sentient Celestial transport craft. This gave him molecular control over his own body similar to that of an Eternal’s, making him not just ageless but nearly impossible to kill. Apocalpyse spent much of the next 800 years hibernating and building up his power.

The Fourth Host

The arrival of the Fourth Celestial Host is what triggered the events of the first Eternals series. The Space Gods were back and had a 50-year mission to judge humanity. They weren’t subtle about it, either, landing smack dab in the middle of a plateau in Peru and throwing up an impenetrable dome.

Thor immediately opposed them and joined with the Eternals in defending the Earth. Odin was cagey about his plans and told Thor to butt out. Meanwhile, the leader of the Host, the One-Above-All, rescued the Eternal known as the Forgotten One from the Deviants and sent him as a messenger to Thor to warn him not interfere with Celestial business.

Finally, years’ worth of machinations on Odin’s part were set into motion. The invincible Destroyer armor he had created was built specifically for the eventual showdown with the Celestials. The gigantic, mysterious Odinsword of Asgard was his weapon. Odin absorbed the life essence of everyone in Asgard and entered the Destroyer. He was joined by the Eternals’ Uni-Mind.

Odin used the Destroyer’s disintegration ray to penetrate the dome and cut off Nezzar’s arm. Nonplussed, the Celestial simply regenerated it. It didn’t take long for the Celestials to turn the Destroyer into a lump of molten metal. The Earth goddess Gaea (Thor’s mother) presented Arishem with the gift of 12 young gods from every pantheon. Arishem ruled in favor of the Earth, the Host left, and the Celestials erased everyone’s memory of the event.

The Dreaming Celestial Awakens

The Deviant Lord Ghaur tapped into the Dreaming Celestial’s essence, becoming extremely powerful. This had a price, as the Dreaming Celestial manipulated Ghaur into trying to free him, only to be thwarted. The Deviants manipulated the Eternals into awakening it, and the Dreaming Celestial was not amused. Only through Makkari calming it down did he prevent the Celestial from wiping out the Earth.

Upon awakening, the Dreaming Celestial decided to observe and eventually judge Earth, standing outside San Francisco as it did so. The High Evolutionary and Mister Sinister tried to manipulate it by tampering with its armor, but the Celestial was already in an odd frame of mind: It was questioning its entire purpose, including its role regarding its master, the Fulcrum. It saved Thena’s son from death and admired Iron Man from afar.

Another Celestial Host popped up to investigate, and the Dreaming Celestial (along with Cyclops) asked them nicely to leave. Apparently, no one had ever tried this before, because it worked!

The Dreaming Celestial went off to a waiting place that resembled a bar. It met the godlike Fulcrum, the Celestial’s chief, in the form of a bartender named Jack (a nod to King Kirby). When the Dreaming Celestial removed its helmet, revealing a humanoid form, it begged the Fulcrum to spare Earth. The Fulcrum was pleased, as this was the first Celestial to rise above its given purpose, and they left this plane of existence to become companions.

Destruction and Resurrection

Things get really cosmic and abstract for the Celestials at this point. A group of powerful interdimensional beings called the Beyonders were destroying iterations of various multiverses by crashing them into each other in what were called "incursions." While all of this was going on, they hunted down and destroyed every Celestial they could find in every multiverse, confident they had killed them all.

The multiverse was then restored, and while most of the Celestials remained dead, a few returned who were hiding out somewhere in space-time. They were attacked by a being called Logos, a fusion of the cosmic beings Master Order, Lord Chaos, and the In-Betweener. Logos wanted to be the cosmic judge, and the Celestials were his competition.

As it turns out, Logos was a pawn of the First Firmament, who had been waiting very patiently to get revenge on the Celestials. Every Celestial was destroyed except one: the One-Above-All, who was saved by a cosmic being called the Queen of Nevers. She was the lover of Eternity, another cosmic being. Eternity represented everything that is, but she was the manifestation of possibilities: everything that could be.

She used the One-Above-All to recreate the Eternals, resulting in the Fifth Host, and they defeated the First Fulcrum and its Aspirants once again.

The Final Host

Zgreb was awakened by that pesky Loki, wanting the Dark Celestials to destroy Earth. As the Fifth Host fell from the sky, apparently dead, the Avengers tried to figure out more about the Horde. They discovered the Eternals had committed mass suicide, as they had learned that they weren’t there to help humanity. They were driven insane when they learned their purpose was to cultivate humanity as a potential cure for the Horde infestation and check in on Earth from time to time to see if the "antidote" was ready.

Ikaris of the Eternals told Iron Man that humans were capable of forming a Uni-Mind like his people, and that their DNA held the key to defeating the Horde. The Horde had reanimated the armor of the dead Celestials on Earth, but the human Uni-Mind utterly shut them down. The Celestials returned to life and helped the Avengers defeat the Dark Celestials. Once again, Earth was saved.

Later, Loki went after the Infinity Stones. He had heard of a place at the end of time called the Quarry of Creation, where the Stones originated, and traveled there only to find that his selection of Stones was completely non-functional there. Furthermore, he saw thousands of Stones just like them, being mined by a group of ancient Celestials. The trickster realized the trick was on him: these Celestials had been mining and sending the Stones out into the multiverse, manipulating it for their own ends.