I think it will have to do with the Reston the canal empire. Remember on the outbound signal mission from ttk. It says that the cabal sent a message to the head of the cabal empire. I have a feeling that the cabal will lead a massive strike on oryx( they probably don't know he is dead) and us guardians. I think the raid will be you going into a massive cabal ship and going to kill the head of the cabal empire. ( I think the head should be a huge psion)