What is the name of the Assassin's Creed protagonist set in Ptolemaic Egypt?

The Assassin's Creed protagonist set in Ptolemaic Egypt is Bayek of Siwa. He is a Medjay, a protector and lawkeeper from the Siwa Oasis, whose personal quest helps lead to the formation of the Hidden Ones.

Assassin's Creed Origins takes place in the first century BCE, during the reigns of Ptolemy XIII and Cleopatra. Bayek and Aya investigate a group known as the Order of the Ancients, the predecessor of the Templar Order seen in later games.

Bayek is not the same person as Amunet, the later name associated with Aya. Amunet is an important founder figure in the Brotherhood's history, but Bayek is the playable male protagonist and the character most directly identified with Siwa.