The Hidden Ones are the direct predecessors of the Assassins in Assassin’s Creed Origins. Bayek and Aya establish the group in ancient Egypt after confronting the Order of Ancients.
Origins presents the Hidden Ones as an organized movement dedicated to protecting people from oppressive power. Members use a concealed blade and follow an early form of the creed, including the principle that nothing is true and everything is permitted.
The Order of Ancients is the group the Hidden Ones oppose in Origins. Centuries later, the Order develops into the Templar Order, while the Hidden Ones evolve into the Assassin Brotherhood known throughout the later historical periods of the series.