I think this theory has probably been explored numerous times before, but I think it is the Forerunners. I have not read Cryptum, so correct me if I am wrong. If the Forerunners are an ancient civilization, and have created the most advanced technology, do you really think they would ALL have sacrificed themselves against the flood? When they collected groups of each species and redistributed them after the Halo Array (Halo Legends, Origins), there must have been a way to transport via black hole or slip space.
I think they have hidden their identity and whereabouts from the rest of existence, and have done so through the Sentinels and other various creations (Guilty Spark). Perhaps it was to overlook galaxies known to be inhabited, protecting them from infection/utter destruction.
The Forerunners have located Cheif and Cortana in the vastness of space, and are sending them through some sort of transport to brief them on an impending danger to the universe.
Again, I haven’t read Cryptum (and please mark spoilers before going into descriptive details), so this may or may not be plausible. What do you think, and who or what do you think it is?
The most likely answer is that the artifical construct that was seen in the concept trailer might have been a portal device. Why do I think this- simple cause of the world that was also seen in the concept trailer, Anyone notice that the entrance to the construct look like the portal thing on Earth. Unless a sentinel wall was built around the planet seen in the trailer then it is most likely a portal to some planet- for some reason I keep thinking of Charum Hakkor but I doubt it’s possible.
> > > It’s a Forerunner Space Vacuum.
> > Made by Dyson.
> > OT: Its definitely Forerunner though it could be different.
> We do know its not a Dyson Sphere. ( I got the joke however.)
It is possible that the planet is similar to the Shield 0459 from Halo Wars that the Warrior-Servants built. The Dyson Sphere, instead of being contained in a compressed slipspace field, is what makes the planet appear hollow inside.
One of the pieces of concept art in that trailer showed landscape curving upwards, so it’s possible.