- last post: 01.01.0001 12:00 AM PDT
How about at some point in the past a group of species formed a covenant (which the new covenant copied when they began worshipping the forerunners) In this old covenant were the Forerunners and the Reclaimers among others. When they discovered the Flood, the old covenant built the Halos as a weapon against them, and the ark, as a protection for themselves against the Halos. Since they could not afford to let the Ark fall to the Flood it was constantly guarded by the most versatile of their race, the Reclaimers (similar to the Elites in the new covenant, they are strong, have good technology, and are intelligent unlike grunts, drones, and hunters) Unexpectedly the Flood may have attacked and destroyed a vast majority of the old covenant, forcing those few reclaimers in the ark to activate the Halos, to preserve at least some of their species.
Now, it just happened that the Ark was located on "earth". When the Halos were activated, the only survivors of the old covenant, the reclaimers, were stranded on Earth. Over time they began to redevelop their society from the beginning. Why they lost the use of their previous technology I am not sure, but it may have been some side-effect of the firing, some period of recharge, where it did not function. During the time of "recharging etc" the knowledge of how to use the technology became dormant in the 'human' brain (Name changed due to changed living circumstances, or otherwise). Due to our versatility, we began to recreate our old technology, and 'quickly' built up from a group of isolated beings, into a fully-fledged, space-faring civilisation. This could explain why 343 Guilty Spark recognised us as the reclaimers, how we instinctively know how to use forerunner technology, how we have managed to adapt so quickly as to be able to combat the Covenant, and how 343 Guilty Spark recognised the Chief's Mjolnir armor, since it was actually a recreation of the old covenant's technology, which we created from our dormant knowledge of the tech.
It also could explain why the Covenant feel so threatened by us (due to our former 'divinity' in their eyes).
By the way, this is all pure speculation, in my mind it all fits together, but others no doubt have their own theory, and will shun mine. I simply offer it as a possible explanation, believe it, or be sceptical about it, the decision is yours.