BEFORE YOU KEEP GOING WATCH THE FOLLOWING STORY/VIDEO FROM HALO: EVOLUTIONS AND ONE STUDIOS:
THE RETURN - http://halo.xbox.com/en-us/intel/related/video/the-return/706d5450-24bc-4904-98d0-a64f69570dbf
Thinking about it after watching the video, I realized: Halo 4 obviously has to take place at least some months/years after the events related to Halo 3. The story the return, also takes place after the events from halo 3, actually 20 years later. The intrigue that the Elite commander is actually gonna look for this “oracle” in order to investigate what the humans are up to might be a foreshadow of some sort of “new” forerunner structure. As we already know, the Master Chief is going to land in what we think is a shield world. Even if it’s not a shield world, im almost 100% sure it was built by the forerunners. We have also noticed that throughout the original halo saga, the oracle never actually revealed the player all of the forerunner structures or in that case, all of the intel related to the halo’s. When the player plays Halo 1, he/she has no idea that an ark and other halo’s exist (not sure about this one, can’t remember). The player only gets to know that Halo is a weapon. On the events of Halo 2, the player discovers the existence of other halo’s and an ark that can fire all halo’s at a same time, wiping out all biological forms, just like the forerunners did. Finally, in the events of Halo 3 (as I recall — correct me if im wrong), the player destroys the ark, however the 6 remaining halo’s are still intact.
Taking a look at Halo 4, we are probably having a new enemy plus the old ones. The Return, actually gives hope that the Elites might discover something that they do not agree with the humas, bringing war upon the two races once again. Maybe this “oracle” the elite commander is looking for has anything to do with the new forerunner installation, where Master Chief is going to drop. Wether he is related or not, Master Chief might find some human troops there, and might either stay there, or try to go back to Earth and either get there or find something interesting in the way, like a something that threatens the existance of humanity. In my opinion, “The Return” might be a foreshadow to halo 4 events. Today, I beat Halo 2 for another time and realized that its ending was a foreshadow to Halo 3 events that i never payed attention to. Right when Miranda and Johnson ask 343 Guilty Spark for the Ark’s location, the cutscene points at Earth (Earth is showed on the screen and Master Chief following). On Earth, there is a forerunner structure that activates a portal to the Ark. However, nobody knew about the through meaning of the cutscene until they played Halo 4. As a result, all the I say will only be guesses for we can not know what will happen until we play the game.
TL:DR - READ MY POST YOU SILLY WILLY