In the Assassin's Creed series, which 2017 game introduced the ancient Egyptian origin of the Hidden Ones?

Assassin's Creed Origins introduced the ancient Egyptian origin of the Hidden Ones.

Released in 2017, Assassin's Creed Origins follows Bayek of Siwa and Aya during the first century BCE. The pair help establish the Hidden Ones, an organization that later develops into the Assassin Brotherhood. This makes Origins an origin story for the ideological and organizational tradition central to the series.

The game's historical plot is set amid the rivalry involving Cleopatra VII, Julius Caesar, Ptolemy XIII, and other political forces in Ptolemaic Egypt. The fictional Order of the Ancients serves as an early predecessor to the Templar tradition, creating a historical counterpart to the Hidden Ones.

Origins is also notable for changing the series' gameplay structure. It introduced stronger role-playing systems, equipment levels, ability trees, and a large open world spanning deserts, cities, rivers, and Mediterranean regions. Although Odyssey occurs earlier in historical time, Origins is the game that depicts the founding of the Hidden Ones.