It's hard to say considering we are supposed to believe that everything is dead, the flood, covenant, forerunners, and precursors... But they already said that the Covenant is pretty much if not completely gone from this next game, the majority of the insurgents were killed when the outer colonies were glassed, the precursors are gone, and the forerunners are supposed to be, but since it appears to be a forerunner world, Im thinking a undiscovered shield world, the game will definately involve forerunners. It would also probably be sentinels and other new forerunner creations considering the forerunners shouldn't see humanity as an enemy or threat