I'd assume that it is about the cabal and more on their origions or heirarachy Destiny - intro to everything Dark below - intro to crota(hive gods and religion ,he's the weakest, or youngest) House of wolves - intro to queen(awoken and fallen, fallen especially adding more backstory and hierarchy info) "Comet"expansion - expands Destiny adding actual story, more on the traveler, the 9(warminds, Rasputin) a little more on hive post crota, more on the house of wolves post raid, and sets up the next 2 which are Unnamed vex dlc - more on vex as a whole, possibly push the offensive since we have weakened their hold by taking out the black garden, possibly the repercussions of disrupting the vault of glass. I'd expect heavy stranger influence on events and more on her elusive faction The forge of the gods - I'd guess cabal to fit in with the others, they probably attack earth or the traveler in a massive assault. Or craft some weapon that will make them the most dangerous, either way it will end with a bang to set up Destiny 2 probably showing the real threat the cabal pose. Either way I'm excited so let's get it