In Assassin's Creed Origins, the protagonist's hometown oasis is Siwa.
Bayek of Siwa begins the game as a Medjay, a protector and lawkeeper in Ptolemaic Egypt. Siwa is an oasis in Egypt's Western Desert, and it serves as the emotional starting point for Bayek's investigation into a masked group threatening his family and homeland.
The game's opening establishes Siwa before Bayek travels through a much larger recreation of ancient Egypt. Major regions include Alexandria, the Nile Delta, the Faiyum, Memphis, and Cyrene. This structure lets the story move between desert settlements, Greek-influenced cities, and rural communities.
Siwa should not be confused with the Faiyum, which is another important region in the game. The real Siwa Oasis lies near Egypt's border with Libya and is known for its distinctive desert environment and ancient Oracle of Amun. Origins uses that historical setting as the foundation for Bayek's personal story.