Kassandra is the canonical protagonist of the Assassin's Creed Odyssey novelization.
Odyssey allows players to choose either Kassandra or Alexios as the playable character. Ubisoft's tie-in novelization, written by Gordon Doherty, uses Kassandra as the central hero, making her the canonical protagonist for that version of the story.
The game is set in ancient Greece during the Peloponnesian War, beginning in 431 BCE. Kassandra is presented as a mercenary descended from the Spartan king Leonidas I, and the story includes locations such as Athens, Sparta, and the Aegean islands.
Alexios remains a fully playable option in the game, so the choice is not about whether he appears in the narrative. The distinction concerns the canonical identity selected for the novelization and related official continuity.