Kassandra is the female playable protagonist in Assassin's Creed Odyssey.
Odyssey lets the player choose between Kassandra and Alexios at the beginning of the game. The selected character becomes the protagonist, while the other appears as Deimos, an important figure in the story. Kassandra is the female option and is presented in the game's historical canon as the central character.
The game is set in Ancient Greece during the Peloponnesian War, beginning in 431 BCE. Kassandra is a mercenary and descendant of King Leonidas I of Sparta. Her journey takes her across the Aegean world, involving Sparta, Athens, the Cult of Kosmos, and the wider conflict between the two Greek powers.
Aya is a major character in Assassin's Creed Origins, while Phoibe is a young companion in Odyssey and Myrrine is Kassandra's mother. Those names are therefore plausible but refer to different roles. The choice between Kassandra and Alexios affects the playable character, but the canonical female name is specifically Kassandra.