Recently, I've been a bit bored, so I decided to replay khddd. When I finished the story, the same question that has been troubling me for a long time came to my mind. What data could DIZ have hidden inside that bottle? I guess that it may just show Sora how to save the hearts tied to him(Roxas, Xion, Ventus etc). But, c'mon guys...it's Kingdom Hearts; there's always a plot twist.? Do you have any other suggestions?

Data regarding possibly, bringing those very that were suffering back.

Data regarding the Keyblade of Return Hearts?

it's most likely gonna be what you said, a way to bring back the lost hearts (Roxas, Xion, and Ventus etc)

Ansem the Wise says that the bottle is "a clue I hope, to finding yourselves or your lost friends in your hour of need"

plus, in Blank Points he also says "While the boy slept his long sleep, I hid the results of my research inside of him, transplanting the data to where it might best serve a purpose. In fact, I would like to believe... Maybe he can set things right. A boy like him who touches so many hearts-- he could open the right door, and save all those people whose lives I've managed to ruin." that was a lot more than I expected... but you get my point. It's most likely gonna have something to do with Sora saving those connected to him.

It could very well be as RikuFangirl says!  Maybe Diz's data is actually some sort of power that helps Sora find the Key To Return Hearts, unless the data is said key itself?

"— 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

 

Literally, that data could be the Key to Return Hearts.

 

Peace!

According to the Dream Drop Distance Ultimania:

 

— 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.

Edited August 14, 20169 yr by Master Eraqus