In Assassin's Creed Odyssey, Socrates appears as a major character and quest giver.
Socrates is encountered in classical Greece and is portrayed through conversations built around questions, arguments, and moral choices. His role reflects the philosophical method traditionally associated with him, while the game places him inside its fictional account of the Peloponnesian War.
Odyssey also includes other historically known Greek thinkers and figures, including Pythagoras. Pythagoras is connected to the game's mythic and First Civilization storyline, which is separate from Socrates' recurring philosophical encounters.
Plato and Aristotle are famous Greek philosophers, but they are not the answer to this question. The game is set in the 5th century BCE, before Aristotle's period of influence, and its depiction combines history with fantasy and invented personal stories.