Heretic Yojimbo is a powerful boss enemy in the game Final Fantasy X, specifically found in the international and HD remaster versions. He is a darker, stronger version of the optional Aeon, Yojimbo, and serves as one of the Heretic Aeons that challenge the player late in the game. Heretic Yojimbo’s role is to test the player's strength and strategy, offering a greater challenge compared to his regular counterpart. Defeating him is required for completionists aiming to face the game's superbosses.