Kassandra is the canon protagonist option in Assassin’s Creed Odyssey.
Odyssey allows players to choose between Kassandra and Alexios at the beginning of the game. Both are presented as the Spartan misthios, or mercenary, and they occupy the same broad narrative role depending on the player’s selection. Ubisoft’s later official material identifies Kassandra as the canon protagonist.
The story is set in Ancient Greece during the Peloponnesian War, beginning in 431 BCE. Kassandra travels through the Aegean world, encountering Spartan and Athenian forces, regional rulers, mythical creatures, and the Cult of Kosmos.
Alexios is not an incorrect character association: he is the selectable alternative and appears in the story in a different role when Kassandra is chosen. Phoibe and Myrrine are important characters, but neither is the player character. Odyssey is also set centuries before the historical periods of most earlier Assassin protagonists.