In Assassin’s Creed Origins, Bayek is a Medjay at the start of the story.
A Medjay was a protector and official serving communities in ancient Egypt. Bayek serves as the Medjay of Siwa, where the game opens in 49 BCE. His role gives him authority to investigate threats, protect local people, and travel through Egypt while pursuing the individuals responsible for a personal tragedy.
The game presents Bayek as one of the founders of the Hidden Ones, the organization that later develops into the Assassin Brotherhood. Origins therefore explores the beginnings of the series’ central order rather than following an established medieval Brotherhood.
Bayek is sometimes called an Assassin because of his later actions, but “Medjay” is his occupation at the beginning. He is not a pharaoh, Roman legionary, or ordinary village guard. Those distinctions matter because the game’s plot moves between Egyptian and Roman political power.