Kassandra is the canon protagonist of Assassin's Creed Odyssey according to the game's official novelization.
Odyssey, released in 2018, lets players choose to play as either Kassandra or Alexios, two siblings descended from Leonidas I. The selected character becomes the playable Eagle Bearer, while the other sibling takes a different major role in the story.
Although the game supports both choices, the novelization by Gordon Doherty identifies Kassandra as the canonical protagonist. This distinction matters because “playable character” and “canon protagonist” are not always identical in games with branching or selectable heroes. Kassandra's story takes place during the Peloponnesian War in the fifth century BCE.
Odyssey is set before the formal historical formation of the Assassin Brotherhood shown in later games. It includes the Cult of Kosmos, Spartan and Athenian political struggles, and the staff-bearing figure known as the Keeper. The game therefore broadens the series' mythology while moving its historical setting much earlier than Origins.