Well, we've wiped out all their leadership in our solar system, we started the war by invading their Exclusion Zone, and their emperor is either coming themselves to kill us in a future DLC or is sending the mother of all armies to annihilate us. Keep in mind, we don't even know what it is the Cabal fear. It could be the Darkness sure, but the only Cabal we know to have had contact with the Darkness are the ones in our solar system. Way I see it, they're Sparta and we're Athens. Sure, when Persia comes knocking, we might team up. But as soon as that threat is over, we're just going to go back to tearing each other apart. It's simply not in the nature of a species that literally blows up planets instead of going around them, to declare lasting peace with their enemy. The Fallen, on the other hand, just want access to the Traveler. And, I suspect, a home