Siwa is the ancient Egyptian region associated with Bayek, the protagonist of Assassin's Creed Origins.
Bayek is a Medjay, a protector and law enforcer from the Siwa Oasis. The game begins in Siwa in 49 BCE, before expanding across Egypt as Bayek investigates a conspiracy and helps establish the Hidden Ones, the organization that later becomes the Assassin Brotherhood.
The Siwa Oasis is located in Egypt's Western Desert, near the border with Libya. Its isolation and distinctive landscape contrast with major centers such as Alexandria and Memphis, which also appear in the game.
Bayek is sometimes described simply as an Egyptian warrior, but his specific role as a Medjay is central to his character. Aya, his wife, is also an important founder of the Hidden Ones.