I saw something a while back about the future war cult found a time machine or something that would show the future but humans couldn't handle what they saw. So they rebuilt an exo they found to use the machine. That exo is none other than the stranger. That why she said she was not born of light. It was also thought that she is from the future were you fail to stop the darkness in the card someone talking referred to a ghost as little light just like the stranger. Idk were I saw this might have been reddit if I find it I will post a link.