The "Voice"

It could be Ansem SOD,"Kingdom Hearts" in some way,the keyblade essence and even Ventus

 

There's been a thread like this before. Anyways, it was revealed (Somewhere in the Final Mix version) that the voice is Mickey's voice.

 

The sequence is called 'Dive to the Heart' or 'Awakening', and the people who expirence it are Sora (KHI), Roxas (KHII) and Ventus (KHBBS)

The identity of the voice has never being revealed. But it's confirmed its not Mickey's. Also considering Mickey didn't know who Sora, Roxas or Ventus were until more or less halfway through their respective games its implausible that it is him.

In my opinion I think it could be Ventus, because in his 'Dive to the Heart' the voice he is speaking to is the new born Sora's so in theory it could be him talking to Sora and Roxas (both of whom his heart is present in). You can also take into consideration that the voice tells Sora (something along the lines of) 'By the time you catch up to him it will already be to late', something Ventus has experienced first hand.

But I think it could also be the keyblade itself speaking to them. The reasons why I think this are because all the people who experience 'Dive to the Heart' are keyblade wielders. But also the keyblade is linked directly to their hearts and when they hear the voice its while they are in their heart.

 

The voice belonging to the keyblade is a much more valid explanation than Ventus only due to the fact that when KH was first made they hadn't thought up Ventus as a character.

And as for me saying the voice belongs to Mickey, that's because in the Final Mix version of the game after Riku's body gets taken over by Xehanort's heartless Riku also hears a voice which is identified to be Mickey's voice.

 

I like to think it's God or The Universe or Carl Sagan.

 

I think it would be Ventus most likely

 

It's been confirmed to be Mickey.