Something recently crossed my mind regarding Data Pad 9 and it's relevance to what Cortana said in the Halo 3 reveal trailer.
First, here is the beginning of Data Pad 9:
"we have to tell people what's 9oing on because it's not right they should be our friends not gods or demons..."
And here is Cortana's words from the trailer:
"I have defied gods and demons. I am your shield; I am your sword. I know you; your past, your future. This is the way the world ends."
Looking back at this I can now make the following possible connections.
Perhaps "I have defied Gods and Demons" is referring to Cortana going against the Majority in the Committee's suggestion of, "Therefore this Committee recommends we factor-in this new variable(The Flood) delicately, if at all."[Data Pad 15] when she started communicating with the Gravemind at the end of Halo 2.
The Minority had wanted to possibly form a union with the Flood, but the Majority warned against it. Perhaps Cortana saw more eye-to-eye with the Minority in that something beneficial could be gained from communication with the Flood, and when the opportunity presented itself, she took it:
Gravemind: Now I will ask, and you will answer.
Cortana: Alright, shoot.
"I am your shield; I am your sword." Could be alluding to the fact that the Assembly of AI's/Committee of Minds for Security has been protecting Humanity from itself and from the Covenant, acting like a shield, hiding certain information that was deemed too dangerous for us to know.
They have also acted as a sword to us, guiding us towards technological advances to better help us defeat the Covenant and for the "survival of the human species for the next 200,000 years."[Data Pad 7]
Finally, "I know you; your past, your future".
"Your past," is most likely referring to the Committee's knowledge of all human history which is roughly supported in this quote, "Their history is littered with empires, crumbling for want of simple openness to so-called foreign beliefs and innovations."[Data Pad 3] This isn't much of a stretch to make considering that almost all AI have access that kind of information.
And "your future" is pointing to the many simulations the Committee is sure to have run to try and determine outcomes of possible future situations that Humanity may encounter, again roughly supported in the Data Pad text here, "We must ensure that all future simulations are free of internal data-censoring and covariate flattening."[Data Pad 14, discussing the human losses of the war]
These are just some things I've been thinking about, I'd like you hear your opinions and see this dissected for better or worse.
Thank you for reading.