The Digimon Lords, or Holy Angels, created nine Digi-eggs in a plan to hatch them in order to defeat the Shadow Lords. Along with one egg found by two unnamed Angel Digimon, the Holy Angels sacrificed their energy and ultimately themselves to give the Digimon within the eggs power. The eggs hatched into ten Mega level Digimon who were able to defeat the Shadow Lords. After a cataclysmic battle, the Digital World was almost completely destroyed by the virus that had created the Shadow Lords. To prevent the virus from spreading into the ‘real’ world, the ten Megas decided that the Digital World had to be completely erased.
One of the Creators, wanting a remnant of the Digital Monsters, had saved the source codes and data of the ten Digimon before the Digital World was erased.
Years later, one man, who would be a member of the new Creators, accidentally unleashed the source codes out into the world’s internet, bringing with it all the data for the ten Mega Digimon, the Angels they were created from, the Shadow Lords they had defeated and the entire Digital World.
The ten Megas were lost, somewhere in cyber space, and in order to find them to defeat the newly resurrected Shadow Lords, their other forms needed to be created. The new band of Creators worked into the night, creating every level of the ten Megas evolution stages. Unleashed once again into cyber space, the codes found their way to ten chosen humans, the Digidestined, or Tamers, who would aid in the Digimon’s evolution to Mega level to once again defeat the Shadow Lords.