The Hidden Ones is the name of the organization founded in Assassin's Creed Origins.
The Hidden Ones are established by Bayek and Aya near the end of Origins. Their purpose is to protect ordinary people and oppose oppressive rulers from the shadows. The group is portrayed as the historical precursor to the later Assassin Brotherhood.
Origins is set mainly in ancient Egypt during the first century BCE. Its story follows Bayek, a Medjay, as he investigates the organization known as the Order of the Ancients. Aya and Bayek's personal losses help turn their search for justice into a broader movement.
The term Assassin is not the organization's original name in this game. Later historical groups and the series' modern terminology connect the Hidden Ones to the Assassins, but Origins deliberately shows an earlier stage in that evolution. The Order of the Ancients, meanwhile, serves as the predecessor to the Templars.