: When the information about the Domain being a Precursors creation came to the
: fore, I could not get his theory out of my head. The Flood was also a
: Precursor creation, a hive-mind capable of vast amounts of data storage
: from the minds of its hosts. I remember at a few points in the Forerunner
: Trilogy, the Domain was said to be guiding those who accessed it, or even
: responding intelligently to them through memories of others that had
: accessed the Domain. So there is definitely an intelligence either inside
: of it, or the Domain itself is that intelligence.

: They said the Domain was destroyed by the Halos. But the Flood was also
: destroyed by the Halos when they fired. It's a bit too much of a
: coincidence that both shut down at the same time.

: We know from Silentium that the Didact in Halo 4 was essentially a pawn of a
: Gravemind. Is it possible that with Cortana accessing the Domain, she too
: has become a pawn of the Flood/Precursors? Have we just been fighting the
: Flood this whole time, only in the guise of their agents, rather than the
: Flood proper?

As others on other sites have theorized, I believe even when they're not directly present, the Flood/Precursors are the omnipresent adversary of the Halo universe.

Sidenote, reading your post reminded me that Cortana has encountered the Domain before maybe, in Human Weakness as the Gravemind allows her to experience memories.