Considered "rebels" by the First Firmament, they wanted a dynamic, diverse and continually evolving Reality where beings lived, learned, reproduced, aged and died to slowly improve themselves through evolution.

At some point during the war, the Aspirants created a now-lost hyper weapon called the Godkiller, a space-borne 25,000 foot (7,600 m) tall humanoid robot that dwarfed even the Celestials themselves.

It was powered by a cosmic artifact later called the Heart of The Voldi (named after the species which would adopt it) and operated by genetically engineered pilots.

At this point, for unknown reasons, a civil war broke out among the Aspirants that led to the Godkiller being stripped of critical parts for weapons.

[2] This initial visit is called a First Host of Celestials, after the chosen planet has been judged to possess the needed properties for an effective "seeding".

The Celestials then return for follow-up visits or "Hosts", during which they monitor the subject planet's progress and make whatever modifications or interventions they deem appropriate.

Collecting a number of natives during the Stone Age, the Celestials begin genetic experimentation to determine the species' future development.

They create two subspecies from the natives: Eternals, Deviants, and a majority "normal" strain that may or may not be modified in some manner that enhances its long-term development.

For example, the Celestials first visited Earth nearly a million years ago and implanted a special genetic code into the early hominids.

[8] Approximately 21,000 years ago, the Celestials returned to Earth for the Second Host and found that the Deviants had created a vast empire across the world based on the continent of Lemuria, where they had conquered most of the primitive human tribes with their superior technology.

The Earthmothers (such as Frigga and Hera) of Earth, however, had planned a peaceful solution and made an offering of twelve perfect humans, which was accepted, and the planet was spared judgment.

[12] On one occasion, the hero Quasar observes a race completely failing the genetic test, with every living creature being destroyed with their planet.

[15] One of the Celestials to first enter into the Abyss left after the destruction of the 6th Cosmos encountered the dark elder god Knull and picked him up to examine him.

Dubbed "Knowhere", the structure also acts as a common port of call (complete with a market and bar) for travelers from all points in the space-time continuum.

The base is administered by its chief of security, Cosmo, a telepathic and telekinetic Soviet space dog originally lost in Earth orbit in the 1960s.

Courtesy of the deceased Celestial's "Continuum Cortex", travelers with special "passport" bracelets can teleport to any point in the universe instantaneously.

This rebirth however had an unforeseen consequence: it provided an opening for the embittered First Firmament, who had been patiently waiting Outside, to attack the newly reborn, and therefore greatly weakened Eternity, with the goal of destroying the multiverse and restoring itself to the center of creation.

Due to the danger it posed, the Avengers of the Stone Age fought the Fallen and defeated it before burying it deep underground in the modern-day country of South Africa, where it was found and awakened by a group of archaeologists after they uncovered the cavern it was sealed in.

The Fallen then summoned the Final Host while killing the archaeologists and soon afterwards was approached by Loki, the Asgardian God of Mischief, for unknown purposes.

In an attempt to learn more about the Celestials, Iron Man and Doctor Strange visited the Eternals, only to find them all dead or dying from self-inflicted wounds.

Together with the rest of his kind, collectively known as the Final Host, they've killed or infected every other Celestial, the dead bodies of whom now litter the Earth, feeding the Horde.

Eventually the world breathes a sigh of relief as the Avengers, combining their powers through the Uni-Mind (given to Iron Man by Ikaris) purged the Earth of the Horde, curing the infected Celestials.

However, the Progenitor also quickly surmised that the inhabitants of Earth had driven it to ruin, so he declared they would have twenty-four hours to prove themselves more good than evil, else he would destroy the world.

He then continues its judgment declaring Emma Frost, Destiny, and Mystique as failures citing them as proof that the civilians of Earth cannot lay their trust in heroes to save them.

[37] Referred to as "space gods" by the Eternals and the Deviants, the Celestials appear as silent, armored humanoids with an average height of 2,000 feet (610 m).

[48][49] They are capable of feats such as reducing the Asgardian construct known as the Destroyer to slag,[50] moving planets at will,[51] and creating and containing entire pocket universes.

The Celestials also have an immune system, consisting of armored behemoths, jellyfish-like antibodies and a swarm creature with wings and tentacles, which can fire blasts from their eye.

[60] Thanos, wielding the Infinity Gauntlet, ranked the Celestials as being on roughly the same scale of power as Galactus, the Stranger, Odin, and Zeus, but below that of Mistress Love, Lord Chaos, and Master Order.

[68] In the alternate reality of the 1998 miniseries Mutant X, the Celestials openly opposed the Goblin Entity, an all powerful being that consumed entire galaxies and the polar opposite of the Phoenix Force.

[69] The Celestials of Earth-4280 were convinced they were gods and attempted to conquer the Multiverse by use of the Bridge, a device created by Reed Richards that allows its users to observe and enter alternate worlds.