Last expansion is focused on the Vex. Some factions of the Fallen become allies. Fourth race of Guardians + Fourth class will come when the Fallen join the Guardians. The Hive will be repelled or completely destroyed. After Oryx we'll have eventually have another Hive expansion where we kill their swarm heart/mind/whatever and the rest of the Hive dies off. The Cabal make an uneasy alliance with Earth and the Fallen but only after their current Emperor is killed (Cabal expansion) and his successor takes over (who is open to alliances). Last raid will be another Vault of Glass kind of thing but on Earth. Vex structures from the far future appear all over Earth. The penultimate boss fight will be Vex versions of the Guardians you're playing from the far future. They've realized that after all the events of Destiny, maybe the only way to beat Guardians is to pit them against their own Guardians. Final boss are five Hearts of Darkness belonging to a massive tree (think The Old One from Demon's Souls) made out of black steel/Vex metal. The Heart of Darkness we beat in the original Destiny game was just a part of this massive thing. The fight has phases which include mechanics from previous expansions and each phase gets harder than the last. At the end of a phase, a Heart becomes vulnerable. Game ends with the Traveler meeting a rogue faction of Vex that are actually benevolent. They decide that all the war throughout Destiny has scarred the universe too much and the only way to save this dimension is to reset it. The Traveler works with the friendly Vex to erase the Darkness and the Light from reality. The universe is altered. The Fallen never become spacefaring because they never meet the Traveler. The Cabal never enter the Milky Way because there is no Vex to chase. The Hive may still exist in some capacity but they won't be completely evil since the Darkness was erased. They probably bump into Humanity eventually but by that point, humanity will be ready to deal with them. The end. Trust me, my dad works at Nintendo.