Me and my friend (bloodwolf 12343) have found that exos may have been human once are evidence is cayde -6 there is picture of a person that has a very big resemblance to him on page 53 of the arms and armaments book it also states the "before his time a great loss but cayde will carry the torch" as well as "cayde got short stick. Stuck in wall , hunters hunt" cayde him self has the same cloak and markings of spades on his armor which leads me to believe that he had his mind and feeling put in to the exo shell