The First Ones were a group of ancient races that achieved sentience billions of years before any of the "Younger Races", such as the Minbari, Humans or Centauri. The most well known races among the First Ones are the Vorlons and the Shadows, who after most of their contemporaries passed beyond the Rim, into the void between galaxies, opted to stay behind and act as guardians and shepherds for the younger races.