What sort of awkward explanation is 343 going to have for co-op Campaign? Forge? Theatre?
Replays allowing Spartan-IVs to improve their battle techniques?
An alternate reality in which John can split himself in four, at which point enemies have the foresight to be harder?
Techies -Yoink- around with the Infinity’s combat deck?
It’s a game.
There’s your explanation.
It’s like some of you want to bring back the “you’re face is canon!” trolling responses 
Anyways, not everything needs to be canon like Forge or Theater. Co-op Campaign should just have Chief clones for the lulz since…well…why not? Not everything has to have a story behind it.
co op campaign has never been truly canon. Halo 3 was as close as it got to true canon.
Yeah, pretty much what A Critical H1T said. Just because they’re trying to put every main part of the game into the storyline, it doesn’t mean that they have to do so with absolutely everything.
But sure, I could see replays being a way for Spartans to review their War Games. And since the holodeck can create any type of environment, Forge could be just some guy(s) modifying battlefields for new training.
Co-op, on the other hand, would be much tougher to explain. But like I said, not everything has to be explained.
And hey, if they don’t say anything about those two, you’re perfectly allowed to make up your own reasons.
> It’s like some of you want to bring back the “you’re face is canon!” trolling responses 
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> Anyways, not everything needs to be canon like Forge or Theater. Co-op Campaign should just have Chief clones for the lulz since…well…why not? Not everything has to have a story behind it.
True.
Also:
Forge: You’re playing War Games on a HoloDeck, who’s to say they don’t modify their maps?
Theater: Again, HoloDeck, in Star Trek, the HoloDeck can record and play movement.
There’s your Canon.
In forge and custom games, you’re a Spartan programming a suitable environment to train in (forge) and then you programme your type of training and play on the environment you designed (custom games).
As for theatre, you’re viewing yourself fighting against all the holograms, I guess.
Halo CE had 2 chiefs, and in the game it even stated that you were the last spartan all the time. I always just thought it was funny. Plus with a brand spanking new holo training room, the explanations for theater, forge, S.O and MM are pretty obvious.
For Co-op Campaign: I’d be surprised if Halo 4 didn’t create characters specifically tailored towards cooperative-campaign. I mean, Halo 3 pulled it off quite well, it managed to include four unique characters for co-op, albeit if the 3rd and 4th character – Usze 'Taham and N’tho 'Sraom – were just stock characters with no depth, personality, or major role in Halo 3’s plot. I would imagine that 343 would implement that into Halo 4, have something like three unique SPARTAN-IV’s to accomdate the Chief on his journey.
If however, 343i are unable to give them any personality or integrate them into the storyline of Halo 4, I guess these SPARTAN-IV could just be customizale characters from the multiplayer mode, similar to Noble 6 in halo: Reach. I don’t see how either of those two suggestions wouldn’t work; they don’t even need the use of ‘simulations’ to explain them.
For Forge: Why wouldn’t the UNSC want to add variation to the SPARTAN’s virtual battlefields? Including new objects and spaces would help them prepare for unfamiliar encounters and locations. Keepin’ them on their toes, so to speak.
For Theater: 343i could explain this by having cameras on multiplayer maps and maybe some in the campaign. A SPARTAN could benefit from watching reccordings of his previous battles.
Campaign: Master Chief recorded the footage, and they’re running a simulation.
Forge: They let Spartans design a simulation map.
Theatre: They replay the footage from the simulation.
The explanations are pretty simple. 
There is that shot in the trailer of the chief with 2 SIV looking guys standing around him…You sir ( or mam) might have hit the nail on the head.
Its campaign screenshot 1
> There is that shot in the trailer of the chief with 2 SIV looking guys standing around him…You sir ( or mam) might have hit the nail on the head.
>
> Its campaign screenshot 1
The Infinity doesn’t enter Requiem for a while into the Campaign, so Spartan IVs won’t be the co-op characters on the first few levels.
That is true, but we have no clue of how the story unfolds before that, and I could see them adding them in as placeholders( Cutscene placeholder, if the coop models are based off other players SIV’s) just for co-op, and having the chief find them along the way.
No 343 employee has out and out said that everything is canon. Or has one? That’d be odd, considering that’s a pretty big blanket statement. But you could pretty easily justify Forge and Theater in particular. If multiplayer is War Games, Forge is the process of designing the battle zones for War Games. You’re going into the database and making a new entry. Theater is the tapes; they record each war game to monitor progress, and I’m sure the Spartan IVs take a look at the stuff to help themselves and each other get better.
Co-op campaign is obviously not canon, and it can’t really ever be. Master Chief has become a loner since the events of Reach; now and again he teams up, but for the most part he goes on missions alone. Personally I would’ve liked if 343 really went with the non-canon of it by making you play as your War Games spartan in co-op campaign. Perhaps it could be claimed to be a simulation to help train Spartan IVs in real scenario that are very relevant.
> No 343 employee has out and out said that everything is canon. Or has one? That’d be odd, considering that’s a pretty big blanket statement. But you could pretty easily justify Forge and Theater in particular. If multiplayer is War Games, Forge is the process of designing the battle zones for War Games. You’re going into the database and making a new entry. Theater is the tapes; they record each war game to monitor progress, and I’m sure the Spartan IVs take a look at the stuff to help themselves and each other get better.
>
> Co-op campaign is obviously not canon, and it can’t really ever be. Master Chief has become a loner since the events of Reach; now and again he teams up, but for the most part he goes on missions alone. Personally I would’ve liked if 343 really went with the non-canon of it by making you play as your War Games spartan in co-op campaign. Perhaps it could be claimed to be a simulation to help train Spartan IVs in real scenario that are very relevant.
Believe it or not, the Elites who are with you in Halo 3 on co-op actually have names and are canon.
True, but they were left out of all cutscenes, almost as if they were thrown in as an afterthought. We have not yet seen FutD, this might be all answered in that as to how the chief ran into SIV’s (or whoever they have designated to be players 2-4).
> > No 343 employee has out and out said that everything is canon. Or has one? That’d be odd, considering that’s a pretty big blanket statement. But you could pretty easily justify Forge and Theater in particular. If multiplayer is War Games, Forge is the process of designing the battle zones for War Games. You’re going into the database and making a new entry. Theater is the tapes; they record each war game to monitor progress, and I’m sure the Spartan IVs take a look at the stuff to help themselves and each other get better.
> >
> > Co-op campaign is obviously not canon, and it can’t really ever be. Master Chief has become a loner since the events of Reach; now and again he teams up, but for the most part he goes on missions alone. Personally I would’ve liked if 343 really went with the non-canon of it by making you play as your War Games spartan in co-op campaign. Perhaps it could be claimed to be a simulation to help train Spartan IVs in real scenario that are very relevant.
>
> Believe it or not, the Elites who are with you in Halo 3 on co-op actually have names and are canon.
Schrodinger’s Elites. They’re both canon and non-canon at the same time!
CoOp campaign.
Player 1: Master Chief
Player 2: a randy elite that also got left behind.
Player 3: See player 2.
Player 4: see player 3.