Nomura said that Roxas is the main secret of KH3.

And I have two theories:

1. Roxas really Ventus as though I did not want it and as though others did not like and as though DDD did not show them separately. For after the advent of Aquanort, I expect everything.

2.Roxas will become nort.

I did a post with this theory on this forum, but with the advent of new information I have even more confidence that this could be true. Nomura promised surprises and unexpected twists and turns, and why is this not an unexpected turn? In addition, Roxas has reasons to become a nort, how to treat him and forcefully against his will shoved in Sora.

I was still very hooked on the theory put forward on tumblr that's literally the words from there: "Nomura saying there will be even more surprises and he’s concerned if we were going to be okay got me thinking… please hear me out (and Roxas fans please don’t kill me ? I love Roxas!)

I think Roxas will turn or has been evil for a while. I mean in DDD when he showed Sora his painful memories he was smiling and I don’t think it helped Sora wake up, in fact he was falling deeper and Ventus was the one who saved him (and Riku).

I think Roxas harbors a lot of feelings of envy and spite toward Sora and it’s understandable. In fact it would make him a VERY sympathetic villain. Because of Sora, he lost so many things and even his right to be. Can’t imagine his suffering right now, trapped in Sora’s body. To Ventus, Sora’s heart is a sanctuary, but maybe to Roxas it is a prison.

Also that scene in the latest KH3 trailer where the org seems very eager for Roxas to return and Xemnas even said nothing would please them more. Maybe some time in DDD they made contact with Roxas?

Anyway I think at some point in KH3 Sora WILL bring Roxas back and then it’ll be like a Top Ten Anime Betrayals scene and Roxas will turn on Sora and pull out Ventus’s heart (or take him with him), making Sora lose his ability to wield the keyblade.

And at some point maybe Kairi and Lea/Axel confront Roxas. And Lea will have to choose between Roxas and Kairi. It’ll be a tough decision to make but he chooses what he believes is right and sides with Kairi. I think maybe Roxas would want to use Kairi’s body to bring back Xion."

What do you think about this and what are your theories about this?

It's a pretty good theory with a lot of twists. I can definitely see Roxas being with the bad guys and he does have every right to be with them. 

 

But we still don't know what kind of data Ansem gave to Sora. Maybe there's a way of bringing back Ventus without having to "hurt" Sora (we've seen crazier things). 

I thought Roxas and Sora amended their relationship in KH2? Why did Roxas willingly return to Sora?

Dream Drop Distance did show Roxas and Ventus separately, and Roxas's memories wasn't meant to wake Sora up. However, Roxas's memories provided Sora a clue that nobodies can have hearts and him discover it at the end of DDD. Plus, Sora giving back Ventus heart won't make him lose the ability to use keyblade. Nomura confirmed himself that Sora was able to wield the keyblade because his own strength of heart. Riku was the original chosen keyblade wielder in KH1 not Sora, however, when Sora decided to fight without the keyblade and that his friends are his power, the keyblade officially chose Sora as his real master instead of Riku. Sora prove himself that his heart was stronger than Riku's heart and because that Sora can wield his own keyblade not Ventus.

I thought Roxas and Sora amended their relationship in KH2? Why did Roxas willingly return to Sora?

Yeah they did at the end of KH2. Even though Roxas accepted his fate as Sora's nobody but you can still tell that Roxas still wanted to be his own person in 358/2 Days, KH2's prologue, and Dream Drop Distance. Sora said so himself in Dream Drop Distance that him and Roxas are not the same and that Roxas deserve to be his own person. And Sora was able to feel Roxas pain and suffering in his heart. Plus, Blank Points, Re:Coded, and Dream Drop Distance stated that Sora can save them from their suffering.