The story of Galactus from Marvel Comics.
In the Comics
Galactus is the sole survivor of the universe that existed prior to the current universe. Originally Galactus was a humanoid named Galan, who was born on the planet Taa, a planet with a very advanced civilization.
But alas, the universe was beginning to fall apart. Like every other Marvel universe, it was a Cosmic Egg, a large group of messy, combined matter. Said mass had a "Big Bang", which split the matter into stars and planets. However, it began to shrink or "crunch" back into one area, shaping into a brand new Cosmic Egg.
The people of Taa were one of the few civilizations left, as the "Big Crunch" spread deadly radiation across the universe. Galan was sent on a journey to find a way to save his planet, but he could find no solution. Soon, the radiation killed most of Taa, so Galan, knowing the unavoidable disaster, gave the idea of putting the remaining people into a spaceship and ramming it right into the Cosmic Egg, killing them all in a spectacular fashion. His idea worked, as they set out into the center of the Big Crunch, where everyone but Galan perished, as Galan was given new energy.
At the moment Galan's universe met its end, the Phoenix Force amassed the positive emotions of all living beings in the cosmos to preserve them from eternal damnation, enabling the Sentience of the Universe — the previous universe's equivalent to Eternity — to meet with Galan. Within the "Cosmic Egg" the Sentience of the Universe revealed itself to Galan and informed him that though they both would die in the final moments of the universe, they would both survive through a joint heir born into the next universe. The Sentience of the Universe merged itself with the mortal Galan and thus Galactus, the devourer of worlds, was conceived.
Eventually, the "Cosmic Egg" underwent another "Big Bang", thus creating the current universe. Eternity and Death, the ethereal embodiments of the new universe, were created in this "Big Bang", and the newborn Galactus was simultaneously hurled outward in his recreated starship.
The nascent Galactus is drifted in his starship for eons as life began to come into existence in the universe, including the races that would give rise to the Elders of the Universe. Eventually, the nascent Galactus's starship was sighted by Ecce of the Watchers, an ancient species who possess vast psionic and energy manipulation powers who had undertaken to observe the events of the universe. Ecce drew the starship down to his planet to study it. There he learned that the being within it had power beyond comprehension and would eventually be forced to consume entire worlds to satiate his hunger for life-sustaining energy. Realizing the danger the nascent Galactus posed to the cosmos, this Watcher considered destroying the entity — who was still vulnerable due to his metamorphic state — but instead decided to abide by the Watchers' oath of non-interference and let the nascent Galactus depart in his starship. Although over time the Watcher race has come to understand that Galactus is an intrinsic and necessary component to the natural order of the cosmos, Ecce has expressed guilt over his decision those billions of years ago and feels partially responsible for the destruction Galactus has caused since.
The nascent Galactus employed his vast power and created a suit of armor to help him regulate his raging internal energies. He then transformed the starship of Galan into a kind of incubation chamber, where Galactus spent thousands upon thousands of years evolving into his current form. Finally, the incubation ship drifted into orbit around the inhabited planet Archeopia. The Archeopians themselves did not disturb the strange ship, but years later a marauding space fleet, nearing Archeopia and thinking Galactus's ship to be a weapon, attacked it. Galactus, with his metamorphosis complete, emerged and with a gesture destroyed the invading fleet. Galactus realizes his uncontrollable hunger for energy, so he turned his attention upon the energy-rich Archeopia below. Galactus immediately consumed the life energies of the Archeopia, only a small fleet of Archeopian ships managed to escape the planet in time. (The Archeopian race would later be fully exterminated by the living planet Ego).
Over the following millennia, Galactus constructed for himself an immense home, the world-ship he calls Taa II, which engulfs the Archeopian solar system as a tribute to both his homeworld and to Archeopia, the first planet he ever consumed. For several billion years Galactus consumed only planets uninhabited by sentient lifeforms, Archeopia being the only exception, and centuries passed between his "feedings".
However, as ages passed, the intervals between feedings decreased considerably in length, and Galactus found himself needing to consume worlds inhabited by sentient races if he could find no other worlds possessing the energy he needs in time to sustain himself. Galactus has succeeded in suppressing his sympathy for intelligent beings who are similar in nature to the entity from which he was birthed, and, realizing himself to be a higher kind of being than they are due to his intrinsic role in the natural order, is willing to destroy their lives to continue his own. Moreover, he is aware that he is meant to one day give back to the universe infinitely more than he has ever taken from it.
At one point Galactus threatened to destroy the planet Zenn-La, home of a civilized, humanoid race. One of that world's inhabitants, Norrin Radd, persuaded Galactus to spare the planet by volunteering to become his "herald" and search out uninhabited worlds for him to consume. Galactus agreed and transformed Norrin Radd into the Silver Surfer.
However, Galactus eventually grew determined to consume the energy-rich planet Earth. The Surfer rebelled as a result, and Reed Richards of the Fantastic Four thwarted Galactus by threatening to use an alien device called the Ultimate Nullifier on him, a weapon that could lay waste to the universe and kill even Galactus. Galactus was forced to vow to spare Earth in exchange for the Nullifier's return, and he punished the Surfer for his betrayal by erecting an undetectable energy barrier that prevented the Surfer from leaving Earth.
Eventually freeing himself from his pledge to Richards by defeating the nearly omnipotent Sphinx (who was further empowered by the secrets of the universe downloaded from the Living Computer of Xandar), Galactus returned several times to Earth to consume it, but was never successful. Meanwhile, he consumed numerous inhabited worlds throughout the known universe to sate his hunger and was feared as a menace to all known starfaring races. Galactus also took on a succession of new heralds.
During his last attempt to devour Earth, Galactus had gone so long without "feeding" that his energies were the lowest they had ever been and he was near death; thus a large number of Earth's superhuman defenders actually succeeded in defeating him in battle. Galactus lay dying, succumbing to his own hunger, but Reed Richards saved his life with the help of Thor's mystic hammer Mjolnir. Galactus gratefully pledged his friendship to Richards and sincerely gave his word never to attack Earth again. Galactus has steadfastly abides by this oath ever since. During this visit to Earth Galactus recruited his latest herald, Nova.
Galactus continues to prey upon other worlds, and recently he destroyed the Skrull throneworld, thereby plunging the Skrull Empire into chaos. There is an account of a far distant alternate future, in which man no longer exists on Earth, and Galactus, therefore no longer feeling bound by his oath, consumes it at last.
At some point afterward, Galactus was targeted by the alien organization called the Elders of the Universe, who believed his death would trigger a new Big Bang and recreate reality. In this new reality, the Elders believed they would become a race a Galacti, each with infinite cosmic power with which to endlessly pursue their special interests. His former herald, Silver Surfer, the Fantastic Four, Franklin Richards, and his herald Nova managed to upset the Elders' plans.
When Nova finally rebelled as his herald, Galactus created another in the alien Morg, who ultimately murdered Nova on his own volition. Morg in turn was defeated by the collection of his heralds, leaving Galactus alone again.
More recently, Galactus' appetite became such that he would only devour the life forces of sentient beings and leave the planets on which they lived intact. He began to consume more and more frequently, because unlike the life essences of the planets he normally feeds on the life forces of mortal beings offer him no sustenance; thus his addiction left him perpetually starving, weakened and demented. He created a new herald, Red Shift, to help him succeed in devouring all of the sentient life forces he came upon. He approached Earth once more, and had to be driven off by a large contingent of Earth's superheroes, and Red Shift was defeated by the Silver Surfer. Finally, the Silver Surfer agreed once more to become Galactus' herald and to search for planets with sentient life to consume.
Almost immediately, the Silver Surfer led Galactus to the homeworld of the Shi'ar Empire, perhaps the most technologically advanced in the known universe, in hopes they would have the forces to repulse the weakened planet devourer. The Shi'ar quickly joined with other races and several of Earth's superheroes to battle Galactus. During the conflict, the Silver Surfer managed to turn Galactus' own energy-siphoning machines on Galactus himself, fatally weakening him. Galactus died, warning that the madness which had consumed him was a precursor to another greater horror. As he passed away, Galactus was converted to energy by his own planet-destroying machines, revealing his true form, that of a sentient star. As Reed Richards noted, his energy would radiate forever outward, so he could never again reform.
Galactus' "death" allowed the being known as Abraxas, the metaphysical embodiment of destruction and the antithesis of Eternity, to emerge from his imprisonment. He soon began to cut a swath of terror through various alternate realities, including the murder of parallel versions of Galactus. He used the decapitated head of one alternate reality Galactus to target and home in on the prime reality Earth and to plant a mole in his version of the Herald known as Nova. On Earth, Abraxas attacked Uatu the Watcher, left him comatose, and stole half of his signature medallion. Abraxas taunted the Fantastic Four with the inevitability of his coming, enticing the team to search for the Ultimate Nullifer, the clues to the location of which were scattered among alternate realities. Ultimately, the Four found the Nullifer when Abraxas suddenly appeared and stole it from them.
Abraxas called forth an army of Novas to attack Earth, and the Fantastic Four held no hope of defeating him. Instead, Franklin Richards, the son of the Four members Mister Fantastic and the Invisible Woman, combined his Celestial-level cosmic powers with those of his sister Valeria and returned Galactus to his natural state and thus restored balance to Eternity, at the cost of forever burning out his powers. Galactus easily wrenched the Nullifer from Abraxas, but due to interference from the army of Novas the Nullifier fell to Reed Richards, who used the weapon to destroy the multiverse. The result served to re-create the multiverse in which Abraxas had never escaped, and since all that was had ended, all that is was realigned, it allowed Mister Fantastic to survive along with all those who died in Abraxas' reign of terror.
During Annihilus' ambition of "conquering" the universe, Galactus was vengefully attacked by the freed surviving Proemial Gods, "Tenebrous, of The Darkness Between" and "Aegis, Lady of All Sorrows", leaving him badly weaken and was, along with the Silver Surfer, captured by Thanos, who was responsible for bargaining the gods into fighting the World Devourer. Galactus and the Surfer were brought to Annhilus and were experimented upon as weapons in Annhilus' war. Galactus was used as a sort of cosmic weapon, capable of destroying whole planets, and his the Surfer's cosmic power were fueled as potential weapons for the Annihilation Wave. Eventually Annhilus' overall plan was to used Galactus as a 'bomb' capable of destroying every life-form in the universe and thus fulfilling his desire of being the only being in the known universe.
However, Annhilus' plan was foiled by the efforts of Moondragon, Drax and the Silver Surfer as they successfully freed Galactus. After teleporting Moondragon and Drax to safety and in his rage, Galactus proceeds to unleash a massive, omnidirectional blast that later becomes known as the "Galactus event." Silver Surfer is sent ahead of the blast by Galactus to herald the imminent destruction, as the unleashed "Galactus obliteration perimeter" wipes out the majority of the Annihilation Wave, more than three star systems and even vaporizes a Watcher. Galactus' action ultimately stop the war and forcing the remaining warring parties to form a truce.
Following the end of the Annihilation war, Galactus became more hungrier than before and have requested his Heralds to find planetary substance to his hunger. It is revealed at some point in the early years of the creation of the universe that Galactus became involved in a civil war between the Proemial Gods. He slayed Diableri the leader of the opposing faction of gods who attempted to gain total control of the universe, and imprisons the remaining surviving gods in the Klyn. Angered and concerned of the freed Proemial Gods Aegis and Tenebrous, Galactus ordered the Silver Surfer in finding and defeating the gods once and for all. After the Surfer kills the gods by luring them into the Crunch, the all-destroying border of the universe, Galactus saved a heavily beaten and exhausted Surfer in which both of them honor their gratitude to each other, and the Surfer once again become a Herald to Galactus.
More recently the Surfer lead Galactus to the planet Sakaar where he destroyed the planet after easily defeating both Skaar and and the Surfer who was being controlled by Skaar. He became addicted to the Old Power after devouring the planet and set out to find all the planets that possesses the Old Power within in them.
Galactus discovered Nu World and its power source. He went to Earth and took Reed Richards to Nu world to fix their power source but in the end Galactus chose to destroy the world rather then eat it for daring to use him as a power source.
Attack on Asgard
Galactus was in search for "Galactus Seed", a cosmic heart that will give birth to the next universe to come. Created by Eternity before the recording of time and discovered by Bor First King of the Asgardians. The seed birthing the World Tree over which the nine realms hang. Surfer arrived on behalf of Galactus for the seed, as quoted by the Silver Surfer, the seed may be able to satisfy Galactus and stop his hunger. Odin refused to hand the seed over to Galactus, believing that Galactus was in search for godhood and wants to live forever. This made Galactus attack Asgard in search for the seed. Galactus was not able to get the seed as Odin was in his way stopping him from getting it.
Galactus and Odin fought by using their telekinetic and telepathic powers because if they had fought physically the power they both possessed would have been able to destroy the Universe. Odin was able to render Galactus unconscious by head-butting him before falling into the Odinsleep. After regaining consciousness Galactus proceeded to attack Asgard in search for the seed despite the fact the Silver Surfer was trying to stop Galactus from proceeding as it declared war on Asgard and Surfer telling him that "They are Gods. They are power and fury and an act of war against a race of Gods is beyond even you..." nonetheless, Galactus proceeded until Odin summoned The Destroyer, which was powered by the seed's energy, and at the same time Loki successfully hid the seed, when Surfer detected the seed was gone he informed Galactus. Knowing that his main objective was not under Asgardian possession any more, Galactus retreated, thus canceling the invasion, and later learned that the seed was lost somewhere within Odin's World Tree, and that searching for it would be like searching for a needle in a pile of space-time.
After the event Surfer proposes a truce between Galactus and Asgardians, one of the conditions is if the Surfer senses the seed disturbed then the war between Galactus and Asgardians continues anew. Needing to stay on Earth to observe the Asgardians and ensure they never retrieved the Seed, the Surfer approached a preacher in Broxton, Oklahoma, Mike, about taking up his role as Herald, having observed Mike's courage in standing up to Galactus for the good of his people. Mike reluctantly accepted the task, becoming Praeter, the latest Herald of
The Future Foundation
Galactus vowed to Reed Richards that he would protect the Earth until the Galactus Seed could be retrieved from Yggdrasill. He gave Richards the means to summon him in the near future, when he foresaw Earth in peril Galactus and the adult Franklin Richards from the future stood toe-to-toe against the Mad Celestials. After they were defeated, Galactus and Franklin bonded over the fact that Galan would no longer face the end of the universe alone—Mister Franklin would survive to the end and witness it with him.
Clash with the Ultimate Universe
Months after his return, Ultron launched a massive attack on Earth, annihilating humankind and conquering the planet. Wolverine was one of the remaining survivors, and used Doctor Doom's Time Machine to travel back in time numerous times until he could prevent Ultron's rise of power and thus the annihilation of humankind, and the evil A.I. was destroyed once and for all, at the cost of the space-time continuum being broken, causing a "multiversal chaos", where numerous beings from other realities were transported to other universes through the tears of reality. Galactus was one of the beings dragged to another universe, in this case Earth-1610.
Galactus' arrival to this Earth happened just in the moment and location in which his counterpart, the entity Gah Lak Tus found itself in the middle of the Chitauri-Kree War. Galactus was approached by Gah Lak Tus, who unexpectedly took the action of merging with its counterpart, creating an even more powerful Galactus with need to feed, who sent part of Gah Lak Tus as his new herald to seek and consume.
When Galactus attacked Hala, the Kree capital, the planet was defended by that world's Silver Surfer, Nova and Captain Mahr Vehl. During the battle, Mahr Vehl died of the injuries caused by the Gah Lak Tus swarm. Nova wore Mahr Vehl's armor and became Captain Marvel, using his newly vast power, and a weapon on Mahr Vehl's armor designed to kill Gah Lak Tus to unleash a powerful attack on Galactus. Thought dead by the heroes, Galactus was only heavily weakened by the attack, and started heading Earth looking to consume its power.
On his way, he was met by Vision as she attempted to return Galactus to his own universe. She failed in doing so and was destroyed. Upon arrival to Earth, Galactus immediately began his path of destruction and preparations to consume the planet. The Ultimates arrived to stop Galactus, but even their most devastating attacks proved to be only a nuisance to the world devourer.
Galactus was ultimately defeated when the Elemental Converter was destroyed by a giant Kitty Pryde, and Thor pushed the cosmic entity through a portal created by Reed Richards, into the N-Zone, with the intention that, since this incarnation of the zone is completely lifeless, Galactus should starve to death.
Return from the N-Zone
Following an incident where the Eternal Ikaris was brainwashed by the Kree using a device called the Gods' Whisperer, he swore vengeance on his would-be captors. With help from Aarkus, Ikaris and his fellow Eternals found the comatose Galactus floating in the N-Zone and brought him back to Earth-616. They then stated that they planned to use the Gods' Whisperer to unleash him upon the Kree when he awakens.
Time Runs Out
In order to stop the incursions, among other solutions, the Illuminati went to Galactus to arrange a meeting with the Celestials- However, before they could fully assure them their help, they mysteriously vanished.
With the renewal of the universe after its destruction, a group of heroes known as the Ultimates started working on problems of cosmic scale that could endanger the universe. One of their first missions consisted of solving Galactus' hunger.
The Ultimates retrieved Galactus' Incubator and forced the devourer of worlds into it, so a new process of similar nature to the one that created Galactus could happen again. Said process was accelerated with Neutronium. After a flash of light and the Incubator's destruction, Galactus emerged anew with a new purpose in life, he became a lifebringer. The first planet that Galactus restored was Archeopia, which had been the very same first victim of his hunger.
When the Ultimates attempted to exit the Omniverse in order to assess the damage time-travel had caused to it, Galactus was tasked by Eternity to stop them. After interrupting the Ultimates' journey and sending them back to Earth, Galactus found himself outside the reach of the omniversal embodiment of Eternity, and discovered the truth Eternity wanted to prevent the Ultimates from knowing, that it was in chains.
Now tasked with the duty to find Eternity' cosmic jailer, Galactus enlisted the help of the Anti-Man to recruit the Ultimates and transform them into his Heralds of Life. Once the Anti-Man assembled the Ultimates and Galactus asked for their help, the Lifebringer was summoned to the Superflow to be put in trial at the request of Lord Chaos and Master Order, two cosmic entities that saw Galactus' new status as a perversion of the cosmic hierarchy.
The Living Tribunal ruled in Galactus' favor, allowing him to remain as his new self, alleging that the cosmic hierarchy in this new reality was still being formed, thus it wasn't set. Lord Chaos and Master Order took this council to heart, and assaulted the Living Tribunal, killing him. Chaos and Order subsequently tried to change Galactus back. However, the same principle that made it possible for them to murder the Tribunal, that there wasn't a heriarchy yet, meant they couldn't impose their will on Galactus, as he was on the same level as Order and Chaos. Order and Chaos left the Superflow, leaving a weakened Galactus trapped behind, and merged into a new more powerful being, Logos. They eventually returned and reverted Galactus back to his old form, bringing him his hunger back, however the Anti-Man sacrificed his powers and his life to revert Galactus back into the Lifebringer. Later, Chaos and Order were defused and the revived Living Tribunal punished them for their actions.
Galactus appears as the main antagonist of Fantastic Four: Rise of the Silver Surfer. He appears as a cosmic cloud which consumed planets and forced the Silver Surfer to serve him by promising not to devour his home planet if he did. The Silver Surfer led him to Earth and only revealed the existence of Galactus to Sue (Invisible Woman) within hours before Galactus was within reach of Earth, as it consumed Saturn. Sue asks Silver Surfer to rise up against his master and save the Earth. As Galactus began to consume Earth, the Silver Surfer decided to defend Earth instead and betrayed Galactus. He entered Galactus and caused a cosmic explosion that seemingly obliterated Galactus in a shockwave of energy (though the Silver Surfer himself survived).
Marvel vs. Capcom 3
Galactus appears in the 2011 video game Marvel vs. Capcom 3: Fate of Two Worlds as the final boss and the main antagonist of the game. When Dr. Doom and Albert Wesker unite their respective universes, hoping to conquer them both, Galactus is awakened and plans to destroy both worlds. In the game, Dr. Doom and Wesker act as two of Galactus' heralds, along with Akuma and Dormammu.
Lego Marvel Superheroes Video Game
Galactus appears in the 2013 Lego Video Game Lego Marvel Superheroes as the secondary antagonist and final boss of the game. Galactus sent the Silver Surfer to herald his arrival before the Surfer was shot down by Dr. Doom's jet. Iron Man witnessed the event and then caught Sandman and Abomination trying to steal the cosmic bricks found in the Silver Surfer's surfboard.
After a long war between the heroes and the villains, Nick Fury revealed to all the heroes of what he realized about the threat; Dr. Doom and Loki were gathering the cosmic bricks to invent a weapon out of them. Fury sent a strike team to their space station to stop them and they eventually defeated Doctor Doom before Loki revealed that the weapon was being used to aid Galactus in his quest to consume Earth and the heroes formed an alliance with all the villains.
In the final battle, the villains and heroes managed to destroy the weapon and receive the cosmic bricks back and managed to defeat Loki and Galactus, sending them both through a portal that cast them both out into space again and away from Earth.
After that, the villains left and the heroes reconstructed the Surfer's board from the cosmic bricks and the Surfer said that he would use it to find Galactus and drive him away from Earth and set out to do this.