I’ve been doing a lot of research and I have found out that John is Bornsteller “Iso-didact”. I think the way it will end is by a huge battle with the Promethean and the created, with the “good guys” being the UNSC, ONI, Covenant/Swords and many other factions. I want you to read about the John-Isodidact theory then listen to my addition.
In the graphic novel composed of all of halo escalations, at the end it says that the Didact is still alive. They say what he is, He is John. What if they Cortana is trying to make sure John can reclaim the mantle. This would explain why the Warden is so hard on Cheif, he’s not attacking, He’s testing. All of the forerunners and Promethean’s know who John is and who he was. They know the plan for humans to reclaim the mantle and they know that they need to prepare for that day. They know that a AI can’t have the mantle because they get corrupted by other means(not rampancy)Look how Cortana turned out, the power is corrupting her greatly. John is perfect for the role of controlling the mantle. I think the way Halo will end is a huge war and Chief Battling Cortana. He says “I’m sorry Cortana” On the verge of tears and “kills” her, then the Warden appear’s and draws his sword with Promethean’s around him, They kneel to him. Cortana appears in her old form saying “You did it John, You always do. This was your destiny to ever since you set eyes on the world. You are the one who must rightfully claim the mantle. It has been the plan for years. You, are the Iso-didact and its your role to reclaim the mantle and restore peace to the galaxy.” Cortana then holds out her hand while Chief grabs her chip.
“Just like the old days” Chief then removes his helmet, all Guardians return, All Troops stop. He pulls a pistol out and shoots A flood infection form. “Cheif, what are you doing?”
“Finishing this fight” And he turns to show his face.