There is a major theory that the location in the Halo 5 Teaser is the Ark. This is the Master Thread, put together by the Archive, for that theory. This will provide the proof and explain how the story connects to it and is supported by it. The complete theory [and will be updated with new additions as time continues]. Enjoy and comment.
Why is it the Lesser Ark?
> Exhibit A. Notice how the two look very similar, right down to the red tint of the planetoid’s oceans.
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> Exhibit B. At first glance, the dark spot in the top left is just a dark cloud. But, perhaps it isn’t that, perhaps it’s actually the darkness of space. If so, the fact that there are no stars would make sense with the Ark being so far away from the Milky Way.
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> Exhibit C. In Rebirth it is said that the IsoDidact buried Mendicant Bias under the sands of the Ark. Now Chief is somewhere that looks a lot like the Ark, and a large Forerunner machine is rising out of the sand. Coincidence? Probably not.
How does the story connect?
> Halo First Strike Definitive Edition “Petra”
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> “A way to stop the Flood. Without firing the remaining Halo rings.
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> A way to stop the Flood.
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> A way.
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> Was she talking about the replacement ring? Absolutely possible; she was obviously knowledgeable about the Portal and where it led, so perfectly reasonable that she could have known there was another Halo installation. Technically, it wouldn’t involve firing the “rings” plural, right?
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> Could the Ark have been a weapon? Details are fairly sketchy-OK, very sketchy-but as the mother of all Forerunner artifacts, it’s certainly not out of the realm of possibility. Although it was meant as a fallback position to fire the Halo rings from, so why would you need to fire them at all if the Ark itself possessed a weapon that could stop the Flood? Or…”
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> Petra further on…
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> “The only cure for the ‘or’ was to find out what the hell the little glowstick was on about. If there was some other instrument of destruction Cortana had set her sights on to use against the nigh-undefeatable Flood… well, that certainly wasn’t going to be a footnote, now, was it?”
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> In Halo Evolutions “Human Weakness” Cortana implies that the Ark itself was the solution.
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> Halo Evolutions “Human Weakness” Page 399
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> “She needed backup. She triggered one of the copies to create a massage to HighCom, a few urgent words about the Flood heading for Earth, the Portal that the Gravemind didn’t know about, and that the way to beat the Flood without activating a Halo Ring lay beyond it - The Ark.”
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> Intereting how Petra wondered if Cortana meant “Rings” plural but in Human Weakness she says “without activating a Halo Ring” singular. So Petra’s speculation definitely has some merit. I also find the way the Librarian speaks of the Ark at the end of Silentium to be of interest.
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> Halo Silentium Page 325
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> “I can only hope that they will survive and upon returning, that they will find this portal and use it to travel to the Ark - in order that they might discover their rightful place in this galaxy and the great responsibility they have finally inherited.”
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> For the most part Halo 3 makes the Ark seem like it’s basically just a foundry for more Halo Rings but the Librarian considers finding the Ark an important part of our self discovery. So what is it? How does the Ark officially help us discover our rightful place in the universe if it’s just a foundry? Does this mean it’s not just a foundry and the “or” that inspired Petra Janecek has something to do with the Librarians plan? The Halo 3 terminals actually bring this up and hint that it’s more than just a Foundry after all.
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> Halo 3 Terminal Three
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> “04-343 (errant): Sincere apology. But how –
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> Explanation: This facility is host to the [Librarians’] final –
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> 04-343 (errant): The archive is intact?! Then our makers’ plan –
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> But also maintains [bellows, crucible, castings]
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> 04-343 (errant): A what?
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> [bellows, crucible]–
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> 04-343 (errant): A Foundry?
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> 04-343 (errant): For what purpose?!
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> Warning: Your intrusion has been logged.
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> Advice: Any further attempt to access will result–
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> 04-343 (errant): Indignant!
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> --immediate addition to local Sentinels’ targeting ledger.”
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> So the Ark being a Foundry was not its primary function and it would seem Guilty Spark knew this. He mentions “the archive” and “our makers’ plan”. What exactly was that? The Ark AI mentions it houses the Librarians something. What ever it is, it’s probably what she thinks about at the end of Silentium and the reason she hopes we find the Ark again someday.
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> The possibility that the thing rising from the desert is Mendicant Bias is an interesting one because it could be part of Cortana’s solution. Remember the unlocked Greg Bear reading of Silentium’s Epilogue where we witness the trial of Mendicant Bias. Why did they keep him alive?
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> Halo Silentium Epilogue
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> “You are brought here to be sentenced. You have not been immediately destroyed because you may yet be needed. Your intimate knowledge of the Flood makes you valuable should they return, but we can never trust you, never again allow you any latitude. You will be entombed here. Your processes locked, frozen into a single thought for all eternity: absolution. Should you be needed you will be reawakened, should there be no need you will be buried here until the end of living time.”
How does it connect to Halo 4?
The Absolute Record.
Episode 9 of Spartan Ops. The Librarian gives Dr. Halsey the Janus Key, which contains the real time location of every piece of Forerunner technology in the galaxy. She tells Halsey to take it to the Absolute Record and use what she finds to propel Humankind. The key was originally meant for her husband.
Mendicant Bias could be the Absolute Record. He is the most powerful Contender-Class Ancilla the Forerunners created. He was close to the Flood, he knew their story and their threat. Now he wants to atone for his sins. He sent the Master Chief to Requiem, and we don’t fully know the Librarian’s plan. Mendicant possesses quite enough knowledge to be considered a “record”.
Mendicant Bias could be Plan B. If the Ur-Didact is unable to help Humanity, they are to take the key instead to Mendicant Bias. Mendicant informs them of the incoming threat, and helps them use the Janus Key to find a means of combatting it.
And the Teaser?
The Master Chief is alone in the desert on the Ark looking for Mendicant Bias, who was buried here.
Perhaps at some point of the campaign he learns of Halsey and the Absolute Record, and goes off on his own to find what it was. He also wants to find Mendicant Bias because Mendicant sent him to Requiem for a reason, and he was interrupted before learning all of the Librarian’s plan. That giant Forerunner Owl-bird type thing, was a Seeker or other Forerunner construct that is guarding Mendicant’s tomb.
