Galactus was one of the last survivors of the universe that preceded the First Firmament. Named Galan of the planet Taa, he witnessed the end of the cycle of collapse and rebirth that had defined the infinity of lifetimes of Creation.
He was plucked from the collapse of his universe by the Phoenix Force and imbued with the Power Cosmic to become the ideologue of Predation in the new order of Creation. Galactus was already old when the Celestials first appeared, and their armored suits are derived from his design. His hunger is endless and insatiable as he exists to consume life that has grown stagnate and ceased to evolve or develop. Entire worlds are stripped bare, resources and minerals extracted, and biomatter gathered and integrated into the living machine that is his personal conveyance, the World Ship Taa II.
Most races see Galactus as a towering representation of their species. Humans see him as a bipedal giant clad in deeply aubergine armor, though a rare few with exceptional willpower or abilities can pierce the veil and behold his true form.
Galactus often empowers Heralds as advance scouts to locate planets rich in resources. Currently his Herald is the Silver Surfer.