GALACTUS was born in the boiling cauldron of the Big Bang. Emerging from the swarm of chaotic quantum potential at the beginning of the universe, he was a pulsing shard of energy - the brightest point in the dark, young cosmos. Unformed, he retreated into a cosmic incubator of his own creation, and there dreamed away the first few billion years of the universe.
As the incubator served to coalesce his form, he created a suit of armor capable of containing his vast energies. As he took on physical shape, however, so he also came to know the hunger that would plague him for the rest of his eternal existence. When he emerged from his long incubation, he found himself in a universe swarming with life. He marveled at the beauty of the planet his incubator had come to orbit - and then he fell on the living world, and consumed it.
So began the legend of GALACTUS - a tale that brings terror to every planet that falls under his shadow. From one end of the universe to the other, the name of GALACTUS is invoked only in whispers, and the coming of his herald is dreaded as the first sign of the end of the world. So vast is his power that entire armadas sent to destroy him are blown apart into radioactive ash by a single absent-minded wave of his mighty hand. So terrible is his hunger that no world can sate him for long. He is as old as the universe, as inexorable as time, and he will not stop feeding until the cosmos itself winds down to its inevitable end.
* All Character biographies/descriptions are from Marvel Universe figure packaging.