There is dead cabal on the map The Cauldron. They are right behind where you spawn near zone A. There is also one fallen vandal dead next to them I forget where but I read a theory that the cabal and fallen are allies and I think that this supports that theory. The hive probably killed them when they we attacking the cauldron and they were probably attacking as allies. I just thought that this was interesting because the cabal are not only on mars and the fallen are the only aliens that have met every other species. Edit: Thats not my picture it's just one I found because I don't want to have to keep playing crucible until the cauldron comes up again.