Kassandra is the canon protagonist of Assassin's Creed Odyssey.
Odyssey lets players choose either Kassandra or Alexios as the playable character. However, the game's wider official continuity identifies Kassandra as the protagonist, including the novelization and later references in the series. Alexios instead appears as Deimos, the opposing sibling in the main story when Kassandra is selected.
The adventure is set in Greece during the Peloponnesian War, beginning in 431 BC. Kassandra is a mercenary and a descendant of Leonidas I of Sparta. Her story explores the Cult of Kosmos, family conflict, and the ancient world that predates the historical Assassin Brotherhood.