Which historical ruler is the protagonist of Assassin's Creed Origins?

Bayek of Siwa is the protagonist of Assassin's Creed Origins.

Bayek is a Medjay, a protector and lawkeeper from the Siwa Oasis in ancient Egypt. The story follows his investigation into the deaths of people close to him and his confrontation with a group whose actions help lead to the creation of the Hidden Ones, the organization that later becomes the Assassin Brotherhood.

Origins is set during the final period of the Ptolemaic Kingdom, around 49 to 43 BCE. Bayek travels through Egypt and encounters historical figures including Cleopatra VII, Julius Caesar, and Ptolemy XIII. These rulers are important characters, but they are not the player-controlled hero.

The title refers to the origins of the series' Assassin tradition rather than to the origin of a single modern organization in the real world. Bayek's wife, Aya, is also a major character and shares much of the historical narrative, which can cause confusion about who is the primary protagonist.