Ok, so one of my friends on Bungie.net named “Ajw34307” is VERY smart when it comes to Halo Universe/Canon stuff. He does a lot of research and reading to find out information of deep halo canon. THIS, post below is made by him completley and i give FULL credit to him. Im not sure if he has an account on here or if he even posts on here but these are his words on the enemy of Halo 4. *Please excuse the first sentence below for it is directed to the OP on B.net. Thanks.
*There is incontrovertible evidence to support that claim.
The Terminals state that Mendicant Bias conversed with the Gravemind for 43 years before forcing itself into Rampancy, defecting to the Flood and betraying the Forerunners. I find it to be far beyond coincidence that the test-firing of Installation 05 at Charum Hakkor - and thus the release of the Prisoner - occurred at the same time and they conversed also for 43 years.
Gravemind states in Human Weakeness that he has consumed many AIs but spared one who joined him long ago, obviously referring to Mendicant Bias.
Primordium’s description states that humans call the Prisoner “The Primordial”, this is the same name Major John Smith uses to describe the Flood in The Mona Lisa.
The Prisoner is known as “the Timeless One”, Gravemind describes himself as a “timeless chorus”.
Gravemind states he has “listened - through rock and metal and time”, the Prisoner listened to the humans and San’Shyuum at Charum Hakkor in his prison for a very long time.
The last words of the Gravemind is “resignation is my virtue; like water I ebb, and flow. Defeat is simply the addition of time to a sentence I never deserved… but you imposed.” The latter part is referring to imprisonment, a sentence he never deserved. The PRISONER of Charum Hakkor, locked away for unknown reasons.
Mendicant Bias given charge of Installation 05 (his serial number was 05-032), the Prisoner stowed away on the Installation he stole - the same Halo we discover the Gravemind on 100,000 years later.
“Child of my enemy,” is a reference to Ancient Humanity - the first foe the Flood fought and lost against.
The Gravemind was in containment on Installation 05 and escaped when Penitent Tangent ignored his containment protocols. The Gravemind cannot have been formed after the breakout because there was no sentient life living there.*
All of this is legit, good reason info and directs to ONE of the enemies to possibly being the flood therefore Gravemind might be in H4. Any Qs please post them