I seriously kinda think it would be awesome if it were a hoax or something metaphorical like the Dragon Scroll in Kung Fu Panda.

I seriously kinda think it would be awesome if it were a hoax or something metaphorical like the Dragon Scroll in Kung Fu Panda.

you had the power to return hearts in you all this time sora

I'm just gonna go out and say it: I REALLY don't know! Let it surprise me!

Utada Hikaru's new song.

Well, whatever is in the box, it contains something that would shock a person and the Master of master's heart is the only thing I could think that could shock someone.

An embarassing picture of Aced at the Christmas party

Jokes aside, I would go with the Master of Master's heart. 

I know what is in the box! Or actually who is in the box!

 

MoM is a troll and the box will be no different. There is nothing noteworthy in the box. He is just trolling, which means Nomura is trolling the fanbase. Trust me.

I am just randomly guessing and think it could be the Key to Return Hearts.

My guess would be the X-Blade, or at least, some fragments of it. But then, if that were the case, then what would be the point of Xehanort and Sora's forces clashing when the box would already have the X-Blade? But still, I guess this, because I honestly don't think that the Key To Return Hearts is in there. That, I believe, resides in the data that Ansem collected on Sora when he was asleep, therefore leading to my belief that Sora's heart will draw out this Key To Return Hearts.

 

If it's not the X-Blade that's in the box, it could be the heart of the Master Of Masters himself! I doubt it could be the true Kingdom Hearts. Something that massive can't be contained in such a small box.

The Key to Return Hearts seems like the most logical answer.

I really don't know... really. I'll just wait and see .

Since the final cutscene in X Back Cover is titled "Heart and Key," this leads me to believe that the box contains a heart, since the Key would obviously be No Name. My guess would be the Master of Master's heart.

Since it will be revealed in the long-awaited Kingdom Hearts III, I bet it's going to be Half-Life 3.

I think Pride is in the box. the box says "X-Super" on it, if you link that up with the Latin 7 deadly sins like the names of the foretellers "super" could be a short for for Superbia, the Latin sin for Pride