After a millennium of destruction by humans, the Earth had become a barren wasteland. Its last protector was the King of Asgard, Thor. Out of nostalgia, he wished for the Midgard of old and was the only one who had interest in the planet until the Devourer of Worlds himself, Galactus, arrived to complete the one thing he never accomplished: to satiate his hunger for Earth.
When he was ready to finally devour Earth and kill the Goddesses of Thunder, Galactus was attacked by King Thor, who returned from deep space with All-Black the Necrosword, and was brutally defeated by him. After their battle, King Thor gave Galactus leave to consume Mars and while Galactus was devouring it, the black blade, that Galactus believed to be destroyed, manifested itself inside the Devourer of Worlds, turning him into the Butcher of Worlds.