I was thinking Ghost was being called Dr. Shim. I kinda have a theory where all Ghosts were at one point scientist during the golden age. Then the traveler took the knowledge from them and input them in little machines. Hence how the ghost are proficient at hacking and knowing the golden age tech.

There are Grimiore cards of Dr. Shim and two others having conversations about Vex and the Warmind. Also there are three skeletal remains when you enter the archive. I think those are the remains of Shim and the two others, Ghost just used his credentials possibly while hacking in. Or, he was transferred via the Traveler to Ghost state and doesn't remember all of his Golden age self. He seems to be kind of an a hole, from the conversations lol