: Saw this from redditor aDineSupremecist and thought it was a pretty
: interesting idea and wanted HBO's take on it: After Halo 5, let's rewatch
: the reveal trailer. We find out that this trailer is not exactly for any
: particular game, but for Halo in general on Xbox One. source

: So let's analyze the trailer: Considering the cracked visor, we know this
: trailer takes place after Chief's fight with Locke. We also see no Blue
: Team, who have been at Chief's side throughout Halo 5.

Except, you know, when the Chief was fighting Locke. Then everyone else did their best to pretend that they weren't there.

: Plus he's wearing
: that cloak, which is absent from Halo 5.

Which, for all appearances, seems to be one of those things 343i came up with when they were stumbling around, trying to figure out what to do with the Chief. It has about as much bearing on the final plot of Halo 5 as the initial Guardian trailer.

: My guess is that he's possibly
: hiding from them, or even the Infinity. Maybe they're dead, and he's still
: hiding for reasons unknown. Maybe everybody believes they can't trust him
: so he has to go on this journey alone, without being discovered, or
: risking the lives of his few remaining friends.

"Now he's on our side, now he's not, now he's on our side, now he's not."

The Chief's reasons for going rogue in Halo 5 were already pretty damn contrived, but they got wrapped up in Halo 5. If Halo 6 starts out again with a split between the Chief and the UNSC deep enough that he has to go into hiding... well, it'd be par for the course for 343i's writing, but it wouldn't be good writing.

: So we then see Chief approach the Guardian. Notice something odd about it?

The fact that it's smaller than the others? That it's distinctly avian in appearance and lacks the grimacing skullface of the others? How it resembles early concept art that was evidently discarded or changed like early concept art often is?

: It's lights are not blue like the ones Cortana controls, it's red/orange.
: The only other time we ever see this color scheme is when the Ur-Didact is
: in control of Forerunner tech. Chief grasps Cortana's former data crystal
: chip, and that's pretty much the trailer.

If the blinkenlights had been blue, that would've been a dead giveaway. Also, 343i probably didn't intend for Cortana to return in Halo 5 way back then.

: Based on this information, I'm willing to bet that this does in fact takes
: place after Halo 5.

343i are not gods. They are not omniscient, they are not prescient. They are not masterminds. They are not David Xanatos. They did not have everything planned out from day one, and all indications point toward Cortana being substituted for Halsey at the last minute as the villain of Halo 5.

: Within a year after the events of Halo 5, Elites are hunting down Brutes.
: Whether or not this date will be retconned, for the moment we can say that
: Cortana is defeated sometime in the next year.

Safe to say, The Return is either retconned or some weird sort of alternate universe. You'd think that "Human-built AIs took over Forerunner everything, wiped entire cities from the map, and then established complete dominion over entire systems" would be worth mentioning alongside "A resurgence with the war against the Brutes."

: The Bastion that the Builder is looking for is in fact the Dyson Sphere
: (Trevelyan). It is too big of a structure (2AU in diameter) to not be of
: some importance to the Forerunners and the franchise.

It's not how big a dumb object is, it's what you do with it!

: Seriously, a 2AU diameter is MASSIVE. Can anybody even do the math on how many Requiems,
: Halo Rings, Arks, etc could fit into that?

Yes.

Assuming that the non-inhabitable areas are negligible in size, a 2AU Dyson Shell has a surface area of 2.812*10^17 square kilometers.

Requiem is incalculable unless we know how many layers it has, and how large each layer is. Assuming that the outer layer is inhabitable, the layers are double-sided, and the layers are 500km thick, spaced out an average of 1,000 km with a 2,000km void in the center...

By the way, it should be clear that I have not made any serious attempt to reconcile this model with the Halo 4 skyboxes, and this is for conceptual purposes only. Requiems actual design will differ greatly.

A(Sphere)=4πr^2

A(Requiem)=4π(1000^2+1500^2+2500^2+3000^2+4000^2+4500^2+5500^2+6000^2+7000^2+7500^2+8500^2+9000^2)= 4.769*10^9 square kilometers, or about nine times the surface area of the Earth if we drained the oceans for living room. The living space available increases dramatically if the individual layers are honeycombed with inhabitable spaces.

The Onyx shield world has enough room for 5.896*10^7 Requiems.

A(Ring)=2πrl

A(Halo)=2π(10,000)(318)=9.990*10^6 square kilometers

The Onyx shield world has enough room for 2.815*10^10 Halo rings.

I have no damn clue how to calculate the Ark's surface area with the tools available to me.

: The Builder said that it would
: be near impossible to take it out of slipspace, but it was moved. My guess
: is that the Sentinels stationed at Onyx move the station when it's
: location is comprimised, and set up a new "planet" elsewhere
: with the station in the same slipspace coordinates. This way you couldn't
: find it in slispace, but would have to find Onyx itself as it was the key.

It was described as being moved out of Slipspace in the Kilo 5 trilogy.

: For all we know Trevelyan has a huge Forerunner population in stasis
: inside of it.

Why would they be in stasis?

: Now you have the Ur-Didact. I'm guessing he controls the Guardian in the Halo
: 5 trailer. Maybe he and Chief need to join forces to take down Cortana?

Maybe he was supposed to make an appearance in Halo 5?

: My
: guess is that he moved his consciousness from the isntallation into the
: Guardian, and hoped to use it against the humans. But Cortana couldn't
: take control of it since he was in it, hence why it's not blue.

What, I wonder, is the Librarian's color? Is it the same as Chant-to-Green's? Do Forerunners have a monopoly on little segments of the electromagnetic spectrum, and is this system shared with AIs? If Cortana decides that blue is such a guache color for Promethean blinkenlights and they'd look much better with a glowy sort of olive drab, does she have to hunt down the Forerunner or AI that owns that bit of the electromagnetic spectrum and buy it off of them? Is it possible for Cortana to change the highlight color depending on her mood? Blue means she's angry, teal means that she's happy with what you're doing, and purplish-orange means that she's never going to talk to you again, baka-Chief.

: Who knows on Guilty Spark. Maybe the Infinity will run into him for all we
: know. Maybe they'll flee to Trevelyan. Anything is up to grabs on those
: two groups.

I'll bet dollars to donuts that he introduces himself as "THE SPARK ETERNAL, KEEPER OF ALPHA HALO AND ALL HER SECRETS!"

Oh, and for some reason, his little monitor face looks like a skull now.

: TL;DR The Forerunners are going to war with Cortana.

*looks longingly at the Ground Command press release.*