Galactus. The World Devourer. The Eater of Worlds. This immensely powerful being has vast cosmic mojo that far exceeds most deities. The oldest being in the universe, he travels the cosmos siphoning the energies of whole planets to sustain himself. Galactus must "feed" to maintain his energies as he keeps the delicate balance between life and death. Not good or evil, Galactus simply...is. He's a force of natural selection that is virtually unstoppable when he is at full power.
While not completely unfeeling about the worlds he destroys, he does maintain a certain level of indifference. He does what he has to do. Even those who attack him to defend their planets don't necessarily provoke his wrath. But, that's about to change shortly as the World Eater encounters a force that he is unfamiliar with in the infinite multiverse. As he crosses over into DC Universe looking for new, compatible worlds, he runs headlong into a group he'll regret setting eyes on.
The Red Lantern Corps
Rage is the name of the game for these guys. These berserkers draw on this aspect of the emotional spectrum to create constructs of red energy. Functioning as anti-heroes (sort of) of the DCU, they don't take kindly to this strange giant that has invaded their turf.
After a brief, highly intense battle, the victor emerges. As formidable as the Red Lanterns are, they are ultimately no match for the Power Cosmic. The Lanterns fall, and, Galactus, always searching for sources of energy, absorbs the Corps' power. But, Galactus has underestimated the true nature of their energy. It acts as a virus, infecting him to his core. Suddenly, the World Devourer is...angry! And nothing will stop an angry, hungry Galactus. Nothing!
Dozens of energy-teeming worlds fall to him. In his timeless life, he has never felt this powerful or been this energized. Corrupted by the Lanterns' rage, Galactus goes back to his own universe to finally devour the one world that has always thwarted him in some way. A world he formerly promised an insignificant being that he would never consume in exchange for said being once saving his life. He's off to decimate the energy-rich planet Earth. As he disappears through the wormhole he creates, another familiar figure from the DCU streaks through it just as it closes (more on that later).
The being who Galactus owes his debt to is none other than Reed Richards, the leader of one of Earth's premiere super teams, the Fantastic Four. Galactus has a complicated history with the FF. Reed is one of the few beings he truly respects. But, now, driven by unfettered rage, he doesn't care about respect or past alliances.
As he arrives on Earth, he encounters a foursome determined to stop him. But the FF is currently indisposed in the Negative Zone. A different team has risen.
Victor Von Doom is the absolute monarch of the small European nation of Latveria. He's a mystic and a scientific super genius on par with no other aside from Reed Richards (although you wouldn't dare tell him that to his face).
Doom is an extreme egomaniac who has sought power on an unimaginable scope on several occasions. He even succeeded in stealing the might of the Beyonder once, a being even more powerful than Galactus! So, when the World Eater comes calling once again teeming with power, it doesn't go unnoticed by the King of Latveria. This power must become Doom's! But, he's not the only super being who has taken notice.
The Scarlet Witch
The mutant Avenger, Wanda Maximoff, has the power to affect probability. In other words, she can make the unlikely happen. That will actually come in handy in this fight.
Galactus couldn't have picked a better time to come to Earth. Not only are the FF in the Negative Zone, but most of the Avengers are off-world also leaving Wanda and one other to "watch the store" so to speak.
Tony Stark, the billionaire industrialist, has one of the most brilliant minds on the planet. His greatest creation is a powerful suit of weaponized armor that has a variety of capabilities. Stark is constantly upgrading the suit making it better, anticipating every threat he possibly can. And his mind conceives of a great deal.
Stark is a mechanical genius of the highest order. He has a suit of armor for every contingency. He even created a suit to take on the Hulk. It wouldn't be too far-fetched if had a "Galactus-buster" suit of armor (he doesn't). But his genius is needed desperately. As powerful as his armor is, it's his brain that will be put more to use.
The muscle is coming from the being who followed Galactus through the wormhole.
Kal-El from the long-destroyed planet, Krypton, is one of the most powerful beings in all of comicdom. Very little is beyond his power. Strength, speed, invulnerability, and heat vision are all part of his arsenal. It also makes him pretty dang unbeatable, too. That and he's powered by Earth's sun like a human-sized solar battery.
But, Superman has never faced the Power Cosmic. It's a power that makes Darkseid's and Doomsday's pale in comparison.
Fight, Fight, Fight
Before the others arrive on the scene, Superman tussles with Galactus in New York City (because everything happens in New York in the Marvel U). He gives it his all, but, against a fully charged Devourer, it's no contest. Time and again, Supes is smacked down mercilessly. The Man of Steel gets some small measure of aid with the arrival of dozens of Tony Stark's remote controlled suits of armor. Aided by the Scarlet Witch's hex powers, the ragtag "team" is able to keep Galactus busy for a few moments while the geniuses devise a plan.
The new red and blue player on the field doesn't go unnoticed by Doom. Through his scientific analysis, he deduces that Superman synthesizes solar energy at an incredible rate. So, if Supes is able to generate such incredible power this many miles away from the sun, imagine what he could do bombarded directly by solar energy.
Stark Industries has several satellites in space analyzing energy sources. One happens to be in orbit in fair proximity to the sun. In order to analyze, the satellite also absorbs. With a few minor computer commands, the satellite can project the energy it absorbs. Using several of satellites as relay stations, focused solar energy directly from the sun comes to Earth. Thanks to the Witch's hex power, the beam is directed toward Superman.
Charged with direct solar energy, every cell in The Man of Steel's body is supercharged. Then, it's on! Intensified solar power vs. the Power Cosmic. It's a clash that could easily level the entire state of New York! So, Supes takes the battle to desert territory by airlifting The Devourer out of the city. The battle rages on while the geniuses go to work on another solution.
Of course you know big brains like Doom and Stark already have some type of technology in place that only needs modification for this type of catastrophe. Developing a large energy siphoning device, the three remaining defenders desperately transport the device to the new battle location. And, it's not a moment too soon.
Even "jacked up" Superman at best was only able to hold his own against a fully "fed" Galactus. Now, with the extra boost he received starting to fade, Stark, Doom, and the Witch arrive on the scene to see Superman getting mercilessly pummeled. But, his heroics have bought them the time that was needed.
The siphon does it's job and begins draining the excess energy from Galactus. The amount of energy being drained threatens to overload the device. Luckily, the Witch's hex power prevents that from happening. Along with the world powering energy, the Red Lantern energy is drained from the Devourer, as well. As that corrupting force is taken from him, Galactus slowly regains his senses.
But, there is another nefarious plot afoot. The energy that has been drained from Galactus is slowly being fed to Doom's armor. This type of power must belong to him! Unfortunately for him, Tony Stark was also involved in this venture. Rightfully not trusting Doom, Stark implanted a virus in the monarch's armor when they were adapting the siphoning device. At a certain energy level, Doom's armor overloads and destroys everything within it. In a blinding flash, Doom is no more, his empty armor collapsing in a smoking heap.
Wishing to move on, Galactus prepares to leave Earth when he's confronted by Superman who insists the Devourer pays for all the lives he's taken. With a simple gesture, he sends Supes back to his own universe with a small energy ball containing power to restore the Red Lanterns.
Iron Man and the Witch make their way back to New York. But, what of Doom? He was destroyed. The world has seen the last of him, right? Stark doesn't believe that. Doom has seemingly died on several occasions and he has vast knowledge of the mystic arts. So, can you really trust you've seen the last of him? Only time will tell.