The concept of the Fourth Host was a cornerstone of one of the most ambitious and mythologically-rich sagas in comic book history. It was introduced by the legendary writer and artist Jack “The King” Kirby upon his return to Marvel Comics in the mid-1970s. The Host made its first official appearance in The Eternals #1 (July, 1976). This series was Kirby's platform for exploring grand, quasi-religious themes of creation, purpose, and humanity's place amongst the stars. Drawing inspiration from Erich von Däniken's “Chariots of the Gods?” theories, which posited that aliens influenced ancient human history, Kirby created the Celestials as the literal “space gods” responsible for mankind's evolutionary destiny. The Fourth Host was the ultimate manifestation of this idea: the gods returning to see if their creation was a success or a failure. The storyline was not confined to the Eternals' own title but spilled over magnificently into the pages of The Mighty Thor, primarily in issues #283-301, where it reached its dramatic climax. Kirby's work on this saga is often hailed for its incredible scope, awe-inspiring designs, and profound philosophical questions, cementing the Celestials as one of the most powerful and enigmatic forces in the Marvel Universe.
The story of the Fourth Host is the final chapter of a history that began when life on Earth was still young. The Celestials' involvement with Earth is marked by four distinct visitations, or “Hosts.”
The Celestials' history with Earth is a foundational element of its cosmic lore, a process of divine experimentation unfolding over millennia.
The First Host departed, leaving their creations to shape the planet's destiny.
This thousand-year truce set the stage for the modern era. Odin, knowing he could not win a direct conflict, spent the entire millennium preparing for the inevitable, desperate to save the human race he had grown to admire.
The MCU presents a fundamentally different cosmology for the Celestials, completely altering their purpose and relationship with Earth. The concept of distinct “Hosts” or a “judgment” of worthiness does not exist in this continuity. Instead, their purpose is one of cosmic procreation. As revealed in the film Eternals (2021), the Prime Celestial, Arishem the Judge, seeds countless worlds across the universe with a Celestial “egg” deep within the planet's core. He then creates synthetic beings, the Eternals, and genetically unstable predators, the Deviants, on these worlds. The Deviants were initially designed to clear the planet of apex predators to allow intelligent life to flourish. However, they evolved beyond their programming and began to prey on the intelligent life itself. To correct this, Arishem created the Eternals, beings programmed to be loyal to him and tasked with eradicating the Deviants from a seeded planet. The true, hidden purpose of this mission is to protect the burgeoning intelligent population. The growth and development of this population generates a massive amount of psychic and life energy, which is required for the Celestial seed to mature. When the planet's population reaches a certain threshold, the Celestial is born in a cataclysmic event called “The Emergence,” which completely destroys the host planet and all life on it. Therefore, in the MCU, the arrival of the Celestials (via their proxies, the Eternals) is not a prelude to judgment, but a countdown to annihilation. The central conflict of Eternals is the team discovering this truth and choosing to defy their creator, Arishem, to save humanity from the birth of the Celestial tiamut_the_communicator from within the Earth's core. This narrative shift from a trial of potential to a parasitic life cycle provides a more direct and immediate threat for a cinematic story, while retaining the Celestials' god-like status and cosmic scale.
The composition and purpose of the Fourth Host were precise and methodical, reflecting the Celestials' nature as cosmic scientists and arbiters.
The mandate of the Fourth Host was clear and absolute: to observe, analyze, and ultimately pass judgment on Homo sapiens. Upon their arrival, they established a base in the Andes Mountains in Peru and fell silent for a period of fifty years. During this time, they did not communicate their intentions to humanity but simply observed and conducted their inscrutable tests. Their very presence was a Sword of Damocles hanging over the Earth. If humanity was judged “worthy” based on the Celestials' criteria—criteria that remained utterly unknown—the planet would be allowed to continue its evolution. If judged “unworthy,” the Celestial known as exitar_the_exterminator would descend and “purify” the planet, cleansing it of all life to potentially start the experiment anew.
The delegation that landed on Earth was comprised of nine specialized Celestials, each with a specific function in the judgment process.
Name | Role/Title | Key Actions and Notes During the Fourth Host |
---|---|---|
arishem_the_judge | The Judge | As leader of the delegation, Arishem oversaw the entire process. He was the ultimate arbiter, responsible for collating all data and delivering the final verdict. He directly confronted Odin and the other Skyfathers, silently withstanding their most powerful attacks. His final gesture—a simple “thumbs up”—is one of the most iconic moments of the saga. |
exitar_the_exterminator | The Exterminator | At 20,000 feet tall, Exitar was vastly larger than the other Celestials. He remained in high orbit, a visible and terrifying reminder of the consequences of failure. His role was singular: to enact the death sentence upon the planet if Arishem's judgment was negative. |
jemiah_the_analyzer | The Analyzer | Jemiah's function was to analyze biological specimens. He was seen collecting and examining various life forms, including humans, Eternals, and Deviants, in glass-like containers. In one notable instance, he even analyzed a captured Bruce Banner, remarking on the unique nature of the hulk. |
oneg_the_prober | The Prober | Oneg was responsible for probing and experimenting on the planet's systems and creations. He was seen examining and testing Deviant technology, human cities, and other complex structures to understand their function and potential. |
nezarr_the_calculator | The Calculator | Nezarr was the cosmic mathematician of the group. His function was to process the immense quantities of data gathered by his brethren, calculating probabilities and evolutionary trajectories. He was also a formidable combatant, creating an illusion of himself to fight Odin directly and withstanding the force of the Odinsword. |
tefral_the_surveyor | The Surveyor | Tefral's role was to map and survey the entirety of planet Earth, from its geography and topography to its ley lines and energy fields. He meticulously charted every aspect of the physical world. |
gammenon_the_gatherer | The Gatherer | Working in tandem with Jemiah, Gammenon was tasked with collecting specimens of all non-sentient life on Earth. He gathered flora and fauna of every description for analysis, ensuring the Celestials had a complete biological picture of the planet. |
hargen_the_measurer | The Measurer | Hargen's purpose was to quantify everything. He measured physical constants, energy outputs, psychic potential, and any other metric the Celestials deemed relevant to their judgment, providing the raw data for Nezarr's calculations. |
ziran_the_tester | The Tester | Ziran's role was to conduct stress tests and push the limits of Earth's life forms and systems to gauge their stability and potential for future growth. He subjected his test subjects to various pressures to see how they would react. |
In the MCU, the Celestials' mandate is not to judge, but to expand their own species. Their process, as orchestrated by Arishem, is as follows:
This makes the Celestials' purpose in the MCU far more black-and-white from a human perspective: their “success” means our extinction.
While no formal “Host” has visited, several Celestials are central to Earth's story in the MCU.
The arrival of the Fourth Host sent shockwaves through every powerful faction connected to Earth, forcing them to react to a threat beyond their comprehension.
Odin, All-Father of Asgard, took the lead in opposing the Celestials. Bound by the thousand-year-old pact, he had spent a millennium preparing for this day. He summoned the leaders of Earth's other pantheons, including Zeus of Olympus and Vishnu of the Hindu pantheon, to form a united front. His strategy was twofold:
Their combined assault on the Celestials was a spectacular failure. Arishem and the others barely seemed to register the attack. With a single, collective energy blast, they melted the Destroyer armor into a heap of smoldering slag, instantly dissipating the Asgardian life force back to Asgard and casting Odin and the other gods down. This confrontation served as the ultimate demonstration of the Celestials' power, proving that even the mightiest of Earth's gods were like insects to them.
The Eternals were thrown into a crisis of faith. Created by the Celestials, they were programmed to revere their makers. Ajak, the Prime Eternal, served as the sole being capable of communicating with the Host. However, over millennia, the Eternals had grown to love humanity and Earth. They were torn between their sacred duty to their creators and their desire to protect their adopted home. Ultimately, figures like Ikaris and Thena chose to stand with Earth, even if it meant defying the gods who made them. They formed the “Uni-Mind,” a powerful psionic entity composed of their combined life forces, in a desperate bid to fight back, though even this proved insufficient.
Led by Warlord Kro, the Deviants saw the Fourth Host's arrival as a moment of supreme opportunity. With the Celestials—their ancient destroyers—and the Eternals—their sworn enemies—preoccupied, the Deviants launched a full-scale assault on New York City. They believed they could conquer humanity and reclaim the planet in the ensuing chaos. Their attack was ultimately repelled by S.H.I.E.L.D. and Thor, serving as a chaotic B-plot to the cosmic main event.
For humanity, the Fourth Host was a terrifying, inexplicable phenomenon. Giant, silent gods had appeared, and the world's governments and military forces were powerless. nick_fury and S.H.I.E.L.D. worked frantically to gather intelligence, attempting to understand the beings' purpose. Their efforts were futile, highlighting humanity's helplessness in the face of such a cosmic context. The general populace was gripped by fear and awe, as the 50-year judgment period began.
The Fourth Host saga is one of the most celebrated in Thor's publication history, defined by several key moments that escalate the tension to a cosmic scale.
The saga begins not with a bang, but with an unnerving silence. Nine 2,000-foot-tall armored beings appear from the heavens and take up positions in Peru. They do not speak. They do not issue demands. They simply stand and watch. This silent, passive threat was masterfully crafted by Kirby to build a sense of dread and mystery. The world's reaction—from military scrambles to news reports to religious fervor—perfectly captured the feeling of humanity confronting something truly beyond its understanding.
This is the central action set piece of the storyline. After a millennium of preparation, Odin makes his move in Thor #300. He marshals the full power of Asgard into the Destroyer and confronts the Host. The ensuing battle is famously one-sided. The Celestials stand impassively as the Destroyer unleashes blasts capable of shattering planets. They endure the blow of the universe-ending Odinsword. Then, in unison, they raise their hands and unleash a single bolt of energy that utterly annihilates the armor and casts the Skyfathers down. This sequence remains the definitive benchmark for the Celestials' power level in the Marvel Universe.
With all opposition defeated, the 50-year judgment period concludes, and Arishem prepares to deliver his verdict. At the final moment, Thor presents himself before the Celestials, offering his own life. This act is interrupted by the appearance of Gaea (also known as Jord, the goddess of the Earth and Thor's birth mother), acting as the voice of humanity itself. She does not fight. Instead, she makes an offering. On behalf of Earth, she presents twelve of the finest specimens of humanity—a group of young, diverse, and brilliant individuals who would later become known as the Young Gods. This offering represents the pinnacle of humanity's potential for good and for greatness. Arishem the Judge accepts the offering. He processes it, and then delivers his silent judgment with a single gesture: a thumbs-up. The Fourth Host then departs from Earth as silently as it arrived, leaving humanity to continue its journey among the stars.
While the Earth-616 Fourth Host is the definitive version, the concept of Celestials judging or interacting with Earth has appeared in other forms.