Right, this is the point where I am going to weigh in because I have covered a lot of these topics in a lot of detail in the last few months based on discussions I’ve had with Bungie’s own Paul Russel - On the Human-Forerunner Connection.
The introduction of the Didact and much of the story told from there was made inevitable in Halo 3 because Mendicant Bias quite literally tells John in the final Terminal of the game that he’s sending him to the Forerunners - this being the reason why the Forward Unto Dawn splits in half and John ends up at Requiem.
“But I want something far different from you, Reclaimer.
And so here at the end of my life, I do once again betray a former master. The path ahead is fraught with peril. But I will do all I can to keep it stable - keep you safe. I’m not so foolish to think this will absolve me of my sins. One life hardly balances billions.
But I would have my masters know that I have changed.
And you shall be my example.”
~ Halo 3, Terminal 7 (Legendary)
This single excerpt tells us that the Forerunners are still out there and the Master Chief is being sent to them as an instrument of Mendicant Bias’ atonement, that which was mandated to him upon the final battle of the Maginot Sphere in the Forerunner-Flood war. In earlier Terminals, the Didact says to the Librarian that he and the other Forerunner survivors will go on the Great Journey, that they will have to go without her, and that they will carry a bitter record of the events that have transpired over their history.
“Mendicant Bias is trying to prevent us from firing the Array. He speeds back to the Ark, but he won’t succeed. Offensive Bias will stop him, and I will burn this stinking menace in your name.
I will begin our Great Journey without you, carrying this bitter record. Those who came after will know what we bought with this [false transcendence] - what you bought, and the price you paid.“
~ Halo 3, Terminal 7 (non-Legendary reroute)
The entire plot with the Mantle was introduced in Halo 3′s marketing campaign through the IRIS Saga, The Cradle of Life, and then Halo 3′s Terminals, but was utterly ignored in Halo 3′s main campaign for… some reason. This is not new. The story that 343 is telling is literally based upon the squandered build-up of a narrative eight years in the making.
And the article of mine that I linked covers the whole “you are Forerunner” line, which is the most misleading piece of dialogue in the entire series since Bungie had completely changed their minds about the human-Forerunner relationship at that point. The original plan changed, just as the original plan for the Flood to be a Forerunner and then Covenant bioweapon changed.
And the Forerunner Saga was written both before, and in-conjunction with Halo 4, but was entirely based upon that which was set up in IRIS and Halo 3′s Terminals in order to fulfil the story that had been set up.
