So hey guys! Let's speculate about the key to return hearts! Do you guys think it s a real key? Or is it just in Sora?

What did Ansem the wise hide in Sora while he was sleeping? He was talking about opening the right door.

In the first trailer of KH3 (E3 2013) we see heartless form a SOS in the air. Are they good and were they just asking for help to sora? Help thel to become human again?

Um....I think you're looking a little too deep into the Heartless formation there. It's just a general shape, they weren't literally trying to spell or say "SOS".

The Key to Return Hearts is probably going to be something in the same vein as the Key that Unlocks People's Hearts from KH1. It'll probably just materialize with a vague explanation and then it'll do it's job and be off on it's merry way.

As for the Heartless SOS thing....pretty sure that wasn't what they were doing. Honestly it looks like a general swarm of shadows so I'm not sure how you saw an SOS form in all of that. 

https://youtu.be/X0T6ezyp5dI

If I recall correctly, only Emblem Heartless have hearts. The Shadow is not an Emblem Heartless.

I think that SOS might have been coincidence. The Key to Return Hearts will probably be another actual key that brings back Ven, Terra, and Aqua. How has yet to be seen.

The Key To Return Hearts is definitely a mystery at this point, but I like how you mention that it could be something inside of Sora!  That'd be pretty sweet!  But, I imagine said key to be a badass, godly Keyblade that at least matches up to the Ultima Weapon and the X-Blade in terms of looks, ya know?  I wonder where they'll find this Key, and how exactly will they go about using it?

"— Before the ending, Riku receives research data from Ansem the Wise. In the next title, will that be the key to bringing back the people who are sleeping inside Sora?

 

Nomura: You could say it’s the key. That data contains the details explaining the way to connect lost hearts." ~ DDD Ultimania

 

Due to this I have reason to believe that Ansem the Wise's data is the Key to Return Hearts. Or at least deeply connected to it. 

 

Peace!

I mean we have such little information about the 'Key To Return Hearts', it might well be a key blade, but I feel that would be too simple, so I am leaning more towards it being a person- Sora makes sense as he does have the power to save those thought lost by being himself, however with BBS 0.2 coming up apparently Aqua finds a way to save Terra and Ven, so perhaps the mystery continues? 

I still think the "Key to Return Hearts" is Sora himself