In Assassin's Creed Odyssey, Kassandra is identified as the canon protagonist in the series' wider lore.
Odyssey allows players to choose between Kassandra and Alexios as the playable character. The game presents them as siblings, with the unselected sibling taking the opposing role in the story. Ubisoft later established Kassandra as the canonical Eagle Bearer in related material, including the novelization and subsequent series references.
Kassandra's story is set in ancient Greece during the Peloponnesian War, beginning in 431 BCE. She is a mercenary descended from King Leonidas I of Sparta. The game includes historical figures such as Pericles, Socrates, and Alcibiades, while its mythological content includes encounters connected with creatures and ancient artifacts.
Choosing Alexios in the game does not make the player's experience invalid; both choices are supported by the interactive campaign. The distinction matters specifically when discussing continuity outside the player's individual save. Kassandra also appears in Assassin's Creed Valhalla, providing an additional link between Odyssey and later series lore.