The Hidden Ones are the ancient Egyptian precursor to the Assassin Brotherhood in Assassin’s Creed Origins.
Bayek and Aya establish the Hidden Ones after confronting the Order of the Ancients, a secretive organization manipulating political power in Ptolemaic Egypt. The Hidden Ones adopt methods and principles that later become associated with the medieval Assassin Brotherhood, including secrecy, intelligence gathering, and opposition to domination.
Origins deliberately places this organization centuries before the historical Assassins of the Levant. The Hidden Ones are therefore not simply another name for the later Brotherhood at the same point in history. The Order of the Ancients is their principal enemy in the game and is presented as an early predecessor of the Templar Order. This distinction is one of the game’s central pieces of lore.