In Assassin's Creed Origins, the ancient Egyptian group that precedes the Assassin Brotherhood is called the Hidden Ones.
The Hidden Ones are founded by Bayek of Siwa and Aya near the end of the first century BCE. Their purpose is to protect ordinary people and oppose abuses of power through a disciplined network operating from the shadows. The group develops the traditions and symbols later associated with the Assassin Brotherhood.
Origins is set in Ptolemaic Egypt, during the period when Cleopatra VII and Ptolemy XIII compete for power. Bayek begins as a Medjay, a protector and law-enforcement figure, and his personal search for those responsible for a devastating tragedy leads him toward the creation of the Hidden Ones.
The Hidden Ones are not the same as the Order of Ancients, their principal enemy in the game. The Order is a secretive power network that predates the later Templar organization. Origins therefore presents the Brotherhood's roots rather than its fully developed medieval form.