I don’t know WHY, but here’s what we know:
The orange ball floating around is a cryptum. Under “artwork” you can see it referred to as such. http://press.xbox360.com/products/p51/halo-4?grp=Blockbuster+Games&event=5
The symbol that appears at the end of the E3 clip is that of the didacts (almost). Since “An ancient evil awakens” is superimposed on top of the symbol, it can be assumed they are related. It’s a safe bet that the voice is the voice of the Didact. Shadow-of-Sundered-Star | Halo Alpha | Fandom
The Didacts symbol also shows up earlier on, on the UNSC infinity http://s18.postimage.org/bytop4ca1/didact.png
The three new AI/robots we’ve seen are apparently used by the prometheans. They are called “Promethean Crawler”, “Promethean Watcher” and Promethean Knight”. Note that these are all artificial constructs, not prometheans themselves. Didact was the forerunner military leader, and as such the Prometheans are probably all on his side. Names are shown when you click on the relevant pictures here: http://halo.xbox.com/en-us/Universe/detail/e3-2012-halo-4-renders/600518a8-d6fd-4c01-9f46-d9a97fcd9cc1#imageNumber=3
So…the big question, why? Well to be honest, I don’t know. 95% of what we’ve learned from the forerunner novels points to him being an ally. I expect the third forerunner novel will explain it better. Greg has perhaps given us a clue: http://www.gregbear.com/blog/display.cfm?id=6513
“Let’s just say there are two Didacts…” That could mean…something?
Also, why are we focused on the Didact when Bears novels made it pretty clear that the precursors are the ones we should be wary of.
Perhaps 343 is just holding back the real enemy for later in this game, or perhaps Halo 5/6. I really want to know what is motivating the Didact to attack the very same species that he gave his entire races legacy to. It makes no sense. The symbol that looks like a variation of the Didacts IS different enough from the one we know that it could belong to someone else but…who knows.
Perhaps the “original” old crotchety Didact that apparently died in Cryptum never actually died, but was tortured by the master builder, put in a cryptum and has forever harbored a severe hate for humanity for basically putting him in that situation (if I had never met those damn human kids this never would have happened!). As opposed to the new Bornstellar Didact who seems to love humans.
Edit: it’s also worth noting that there are two different colors of all the enemies. The first ones are all orange, but in later images they are blue. That could hint at 2 factions of these, or perhaps they switch sides eventually. http://i.minus.com/igCbP7w5g2pIm.jpeg
