Cayde-6 is an Exo who served as a Hunter Vanguard. Exos began as self-aware war machines developed by humanity on the moon Europa during the Golden Age for a long forgotten war, with the sole purpose of protecting their creators. They were rebooted during the Collapse and now have no memory of their original function. Exos are so advanced that nothing short of a Ghost can understand their inner functions. Cayde is also the owner of the Ace of Spades. 