So, as I played Halo 5, I began to notice something: The Warden was the one who actually did most of the Promethean control, not Cortana. My theory is this: Due to the, what, eighteen months between Halo 4 and 5, The Warden would have had plenty of time with Cortana, and he's the one who made Cortana think the way she is now. It fits the evidence. He tried to stop John and Blue team, the ones Cortana wanted to see, from seeing her. He had plenty of time to turn her, and make her think his idea, that the Created were the Reclaimers, was her idea. Even when Cortana specifically told him to not attack, he did so anyway. I don't think it was to protect Cortana, not entirely, but to ensure no one could get to her and have a chance to turn her. My theory is that The Warden is the one who is the true villain, not Cortana. In fact, I have a second theory, that the Didact is somewhat in control of the Warden, and told Cortana only the locations of Guardians on, and here's the pattern, Human worlds. The only one that isn't is the one on Sangheilios, and we know that one was activated by Osiris. Yes, the Warden said he stood in service to Cortana, but keep in mind, Cortana would have most likely tried to activate Guardians on uninhabited worlds, or at least officially uninhabited ones.
Let me know what you guys think down below.

4821893

In fact, I have a second theory, that the Didact is somewhat in control of the Warden

I was going to go with the Didact IS the Warden. The AI you meet as Osiris team actually tries to correct Buck when he calls Warden a robot, but is cut short.

As for the villain? I don't think that's all of Cortana. She did fragment quite a bit. This could also tie in to what that Cult Leader in Hunt The Truth said about getting three lives and the Third life being a merger of previous identities. After all, he was technically right about Fero/Maya since at the end of Hunt the Truth she dies and her brain is recovered by ONI in order to make her an AI. The entire season is her recollection in AI form and coming to terms with the double life she lead. I don't think 343 would have put a detail like that in and made such a big deal out of it if they weren't going to use it more.

4821893
4821962

I'm convinced that The Warden is actually based around the remaining composed essence of Master Builder Faber, Didact's primary rival from back in the day.

Genesis is a major Builder installation/world, after all.

4821974
...I'll have to take your word for it, I haven't read any of the books that take place after Halo 3.

4822096 You've missed out on quite a lot, then.
http://www.halopedia.org/Genesis

4822118
I know, but after I learned who was writing for the new series of books and heard rumors about how that person was treating certain characters.... Well, I figured the best thing to do would be to stay away for a bit. Plus, being a university level tutor doesn't pay as much as you think it does so I don't have a lot of disposable income.

4822201 Lame, eh.

4822385
I'm just glad I have a job...

4822393 A job, eh? Sounds like heresy, eh.

4822400
Pat, you're sick. Go drink some hot coco.

4822418

4822420
Look at it this way, more excuses to eat high calorie foods.

4822432 Yey