In Assassin's Creed Origins, Bayek is a medjay from Siwa, an oasis town in Egypt.
Bayek is the game's protagonist and one of the last medjays, a traditional protector and lawkeeper. The story begins in Siwa before expanding across Ptolemaic Egypt. Bayek's personal investigation into a masked group gradually develops into the origin story of the Hidden Ones, the organization that later becomes the Assassin Brotherhood.
Siwa is a real oasis in Egypt's Western Desert, located near the border with Libya. Its isolated setting helps explain Bayek's local authority and his distinctive connection to the community. The historical game is set during the reign of Ptolemy XIII, amid the political conflict involving Cleopatra and Julius Caesar.
The title Origins is important because the game moves backward in the fictional history of the Assassin-Templar conflict. Rather than depicting the established medieval Brotherhood, it shows how the Hidden Ones are formed after events involving Bayek and Aya.