system
Given the following post, respond as if you're commenting on Reddit:
human
[Halo]How did the forerunners 'fake' human prehistory?

To clarify, as far as I can understand, ancient humans were obviously de-evolved by the forerunners after their war. But, what I don't understand is how did the humans that rose up afterwards, not notice anything odd; Because in my mind, that would imply to me that the forerunners were able to plant fake fossils or something like that to throw off the next iteration of humanity, since they would inevitably rise up again.

So, in short, did the forerunners do anything to make the humans oblivious to their past, or is there a plot hole in regards to this?
gpt
The majority of the forms the Forerunners devolved ancient humanity into had already existed earlier in mankind's evolutionary chain. A few were mutations but from a historical perspective that would just like a species diverging with a few missing links.

Before activating the Array, the Forerunners covered every life-bearing planet they could find with a substance called Solute. Its purpose was to ensure that every lifeform affected by the Array (which is pretty much any animal with a nervous system more complex than a starfish) would disintegrate into its component molecules. No bodies, no bones, no fossils. This was done to prevent an ecological disaster across the galaxy. Having billions of rotting bodies all at once would not be good for any environment. However it had the secondary effect of potentially muddying up a fossil record as it would leave gaps between species that would never be filled.

On Earth, it wiped out the species of humans not already indexed by the Forerunners -homo sapiens, homo neanderthalensis, homo floriensis, denisova hominin and a few others- and, for the most part, any trace they'd ever existed as it takes about 10,000 years for organic material to fossilise (where it would then not be affected by the Solute, thus explaining why there are still dinosaur fossils) and it was only around 9,000 years from the end of the war to the firing of the Array.

Also, while the Forerunners were de-evolving humanity, they also took the time to physically dismantle every trace of human civilisation they could find. They pretty much erased almost all physical evidence that it had ever existed, save for a handful of ruins on some remote worlds. Absolutely nothing was left on Earth.