So yeah, I think ‘The Weapon’ we saw in the trailer could actually be the real Cortana in disguise.
Let me break it down.
From what they talk about, it’s clear that there was a mission before the start of the game, that hasn’t gone according to plan. The Weapon was taken to Zeta Halo to infiltrate and ‘replace’ Cortana, and Chief was meant to extract and deliver her to Infinity. But something went wrong. Perhaps the Banished showed up and threw a spammer in the works?
The Weapon says that Cortana has been deleted (though neither of them know by who), and that she was supposed to delete as well, but mysteriously hasn’t.
I think this is a lie.
I think it’s more likely that Cortana beat her digital duel with the Weapon, and instead replaced it to further her own goals. This way, she gets to operate with everyone assuming she is out of the picture, and can manipulate Chief into unwittingly helping her out.
343 might be just flexing their animation skills, but the Weapon does come off as a little ‘overacted’, as if it’s actually the real Cortana trying to pull off a more bubbly personality to win Chief over.
And I think Chief might be suspect of it.
In the grand scheme of things, finding out why the Weapon (an ally to the UNSC) didn’t delete, seems oddly low priority for Chief in the moment. Chief also turns from being quite dismissive of her, to being responsive and urgent. I think he wants to get the Weapon back to the UNSC for possible deletion, in case Cortana is playing a trick.
As a side note, one of Bungie’s ideas for CE was to have Cortana turn evil before the end of the game. 343 keep telling us Infinite is a spiritual reboot. It would be quite fitting for the Weapon to be revealed to be the evil Cortana before the end of the Campaign.
It would also give 343 a potential ‘out’ for Cortana I the future, if they wanted to pull some kind of save for Cortana by combining her memories with the Weapon’s personality. Not a perfect plan, but the option would be there.
Just a crazy tinfoil theory, but I thought I’d throw it out there.