Assassin's Creed Odyssey begins on the Greek island of Kephallonia.
The opening chapters introduce the player character as a mercenary living on Kephallonia. The protagonist can be chosen as either Kassandra or Alexios, and the early quests establish the character's relationships, debts, and connection to the wider conflict spreading across the Greek world.
Kephallonia is the game's starting region before the story expands to many locations in the Aegean and mainland Greece. The setting is the Peloponnesian War, which began in 431 BCE, and the game combines historical figures and places with the series' fictional Isu mythology.
Kephallonia is sometimes written as Cephallonia or Kefalonia in English sources, reflecting different transliterations of the Greek name. Those spellings refer to the same island. Crete and Rhodes are also real Greek islands featured in the game's broad world, but neither is the opening location.