This is largely based on a post I saw a while back (Ttk had just been confirmed) by a person named Blitz and the lore series by myelin games, and in a recent episode he said "this is where the story lines start to combine" So pre-alpha had mentions of another warmind on mars called Charlemagne, and a place called "Charlemagne's vault" where the player would get thorn, but the whole story line was scrapped. However, they could bring Charlemagne back in without changing the story line. Hear me out: Clovis Bray was a big player in AI development, and they're located on mars. One of the heads of the company, Willis bray, also had a big role in the making of Siva. She also had conversations with general Chen Lanshu (documented in the raid armor; full Reddit post here https://m.reddit.com/r/DestinyTheGame/comments/55gnzj/the_flavor_text_on_the_raid_gear_is_a_conversation/ ) in Myelin games' video, he suggested that general Chen had been given knowledge that the darkness was coming via an early prototype of FWC's future vision machine that drove people insane. This led Willa Bray to begin work on Charlemagne because she felt that Rasputin was not enough protection against the darkness. However, the sometime after the collapse, Charlemagne was lost or destroyed. I have thought of another possibly that Charlemagne is on Europa (but controlled on mars) and was tasked with defending the outer solar system, but failed or possibly taken over with Siva (similar to how Rasputin was in control until Siva took control). This could also explain why the cabal are on mars, as they want to try and find a way to disable Charlemagne so they can have a full force invasion on Earth and the Traveler, and maybe take over/destroy the traveler. I may have left out some small details or if you have any thoughts you can add them.