In Assassin's Creed Origins, Bayek's official occupation before becoming an Assassin is Medjay.
Bayek of Siwa is a Medjay, a protector and lawkeeper serving communities in Ptolemaic Egypt. The title has historical roots in ancient Nubia, where Medjay originally referred to a people and later became associated with elite guards or state agents. Origins uses that tradition as the basis for Bayek's role and identity.
Bayek's duties take him across Egypt, where he investigates threats, protects civilians, and pursues members of the Order of the Ancients. His personal quest, combined with Aya's activities, leads to the formation of the Hidden Ones, the organization that later develops into the Assassin Brotherhood.
Bayek is sometimes called a warrior or bodyguard in general descriptions, but Medjay is the specific title used for his occupation. He is not a pharaoh, senator, or gladiator, although the game includes people and locations connected to all three categories.