Kassandra is the canon protagonist of Assassin's Creed Odyssey's official storyline.
Odyssey lets players choose Kassandra or Alexios as the playable character, but the wider franchise treats Kassandra as the canonical version. The game's novelization also follows Kassandra, making her identity the standard reference for the protagonist outside the player's individual choice.
Kassandra is a Spartan mercenary whose story takes place during the Peloponnesian War in the fifth century BCE. The game features a large ancient Greek world, branching dialogue, naval exploration, and decisions that can alter parts of the narrative.
Alexios remains a valid playable choice within the game, which is why this fact is often misunderstood. Canonical status refers to the continuity used by the official story, not to whether players are permitted to select Alexios during gameplay.