The Endless Nothing was a realm which disappeared after things were made. The great Infinity Dragon once appeared out of nowhere and created the Infinity Dimension, which destroyed The Endless Nothing as there wasn't nothing anymore. Once, Gaia lived there, because Kairos used his Chronomancy to send her back to long before even their father (Infinity Dragon) existed, to before anything was made, and thus The Endless Nothing. Gaia was later brought back when Kairos got regret. The Endless Nothing bordered the universe, where the Big Bang took place years later, but they are not the same.