I’ll try and keep this short, but I just watched a video by Darkside Royalty Lore called The fate of the Queen, Petra’s BETRAYAL, and WHY Uldren killed Cayde: url=http://youtu.be/le8iSaCD7oU]link[/url] mostly about why uldren want to kill cayde. So basically, Petra and uldren are working together (telesto lore), and lure cayde in to the reef. Now, here’s where his theories and my theory split. I believe that back in TTK when Eris morn says “My queen” she is not talking about savuthan, but about Mara sov. And, Eris is just a pawn for Mara. We’ll loop back to this in a minute. Let’s talk about why they drew Cayde in, not us, not ikora or Zavala or Osiris, but cayde. Who is cayde? The hunter vanguard. And what class was eris(before she lost her light). A hunter. Now, I believe that when they kill cayde, Uldren and Petra know that they will fill the hunter vanguard position with a hunter, and since Eris is still in Ikoras favor because she was/is (most likely now a somewhat double agent for the reef) one of the Hidden, they think that the consensus will fill the position with Eris. What would the reef have to gain from this? A spy (sort of, since they aren’t officially at war) at a higher position in the city. And someone who would teach the hunters that the awoken are great. Oh, and someone who would be in a position to send us (who is the strongest single entity in the solar system) to help the reef. Just a theory, please upvote and comment, and for more theories check out that video (link above) by Darkside royalty lore. Pretty great video.