Here is my theory. so the first expansion pack for destiny is called The Dark Below and this is its description " In The Dark Below, you'll discover an ancient tomb has been unsealed. Beneath the surface of the Moon, a dark god has answered centuries of prayer, and a dark army has risen. Explore the true depths of the Hellmouth. Stop the dark Hive ritual and survive." now if you have finished the main story you will know that it has a heavy vex back story detailing about vex and there god being the Heart of Black Garden and in destiny lore , 3 out of 4 enemy factions have religious back grounds(as i am aware of) and the Hive have there god which is Oryx. Name sound familiar? well theres a group in the hive called Blood of Oryx and you can distinguish this group by there fraction colour of purple , most notably the mission boss Sardok, Eye of Oryx is of this faction . Now Oryx has a champion which is Crota and in the game we find out that crota is not dead but merely asleep and that his sword which was used to kill many guardians still lives. Crotas sword is protected by the swarm princes there description is "the Royalty of Nightmare. The Swarm Princes are terrible legends. It was their will that forged the Sword of Crota, a weapon meant to ravage worlds - the Great Render of Light, the Darkest Edge. They have waited in the shadows of the Hellmouth for their master's return, guarding the Sword and sating its ravenous hunger with the Light of Guardians who have dared to challenge them."Now after you finish that mission the Sword of Crota never gets destroyed it just vanishes and your ghost just shrugs it off and you move on so most likely the sword may have been returned to Crota's tomb or maybe some hive wizards ( witches, because there female) summoned it back to them for safety. and the only way Crota could be risin up would be by the Hive faction called The Spawn of Crota " Crota's spawn will snuff out the worlds of Light, and Oryx's coming shall be unfettered" SO in turn i believe that the expansion pack would be mainly about Crota and Oryx, Crota will get revived and we will have to destroy him and his spawn which we will learn heaps of lore about the Hive( i hope we get to battle the Hive God) and possibly a Raid involving Hive with hopefully Oryx being the Boss ( :p that would be cool) as the first vault is Vex so in fashion the next vault in the Expansion pack will be Hive. What do you guys think ? Crota the champ and Oryx the God or other way around and do you think Crota could be an Ogre with a Massive sword :p frankly im glad that the next one is hive. I find them to be a awesome faction. By the By all this Lore can be found in your Grimoire cards , do read them if you love game lore :3