The Forerunner Saga was epic, especially the third book, Silentium. And while it tells the story of the Forerunners’ final days, the Didact and the Librarian, and even 343 Guilty Spark, it’s really about the origin of the Flood.

These three books toy with the reader as they slowly uncover parts of the truth.

First, they reveal that the Forerunners destroyed their creators, the Precursors.

Then, they explain how humanity found an ancient powder that caused disease and mutations… with the strong implication that the Precursors developed the Flood as a biological weapon.

Then Silentium brings it all together and reveals the terrible truth:

Some adopted new strategies for survival; they went dormant. Others became dust that could regenerate our past forms; time rendered this dust defective. It brought only disease and misery; but that was good, we saw the misery and found it good.”

Yes, in a failed attempt to protect themselves from the Forerunners’ genocide, the Precursors turned themselves into the Flood.

I’m pretty sure it’s no coincidence the wording of that chapter echoes the Book of Genesis. The Precursors are essentially gods. They created the Forerunners and countless other species, and when they decided to pass the Mantle (in general terms, responsibility for all life) to humanity instead, the Forerunners opposed them.

We are the last of those who gave you breath and form, millions of years ago.
We are the last of those your kind defied and ruthlessly destroyed.
We are the last Precursors.
And now, we are legion.

Forerunner technology is far beyond what humans the Covenant are capable of, but Precursor technology borders on incomprehensible even to the Forerunners. For example, Silentium shows us the Star Roads, roads the Precursors used to bridge planets and possibly move stars. The Flood weaponizes the Star Roads and uses them to surround enemies, crush planets, and prevent slipspace travel.

All Precursor technology operates on the principle of “neural physics,” which believes the universe itself is a living organism beyond our limited understanding of life.

That’s pretty cool, until you remember what the Flood does. The Didact suggests the Flood is capable of infecting the universe itself. Whether or not that’s true, it’s at least implied they can manipulate space and time with tech like the Star Roads.

As for the Didact, a good part of his Halo 4 insanity came from a “conversation” with the Gravemind. (The other part came from being locked in silence for millennia, because while he should have been in contact with the Domain, the firing of the Halos destroyed the Domain because it was secretly a Precursor construct.)

That all sounds Lovecraftian, but there’s one big difference from the sorts of horrors H.P. Lovecraft wrote about. Lovecraft’s cosmic horrors often aren’t actively malicious. We’re just like bugs to them. Insignificant. They’ll destroy us and drive us mad, but not because they hate us.

The fallen Precursors, on the other hand, have a single hate-filled goal: that “all creation will tailor to failure and pain, that never again shall the offspring of the eternal Fount rise up against their creators” (175).

So, what sort of enemy do we have in the Flood?

Twisted gods whose only goal is pain and destruction and revenge, who share a collective consciousness and collective memory, who have the power to subvert human and machine alike and possess technology beyond our understanding.

Yikes.