I have been thinking lately about Kairi's role in KH3 and so far I have been trying to set all the puzzles together and now I think I actually have come up with an likely suggestion. Ever since Kairi was living peacefully in Radiant Garden there was one day when she was attacked by the darkness trying to harm her but a miracle happened and a young woman named Aqua came to her rescue. Kairi full of light saw Aqua as someone she could trust and gave her flowers she had picked in the garden. Before Kairi left to go with her grandma Aqua put a magic spell on Kairi's necklace that whenever darkness would attack her she would find a light to keep her safe( sending her to the Destiny Islands). All this time Kairi haven't rumored Aqua but for sure Kairi does remember Aqua in her heart. Kairi doesn't know that Aqua is trapped in the Realm Of Darkness but her heart must sense that Aqua is in need of help. Im pretty sure that at the end of DDD when Kairi shows up at Yen Sid we see a very serious version of Kairi looking up like she's ready to do something to save someone which I predict is Aqua she's thinking of. The strong connection Kairi have with Aqua is that she's been having since she was four is her necklace she have never taken it off and been wearing it the whole series. I think Kairi will be the one to save Aqua from the Realm Of Darkness it all makes sense now they been sharing their connection through the necklace and having Kairi save Aqua will have a strong and emotional moment. Aqua once saved Kairi and now it's time for repayment Kairi knows what she has to do she will save Aqua from the Realm Of Darkness. 

is possible and i would like this to happen maybe with someone with affinity to that realm like riku and/or riku

meanwhile sora with mickey awaken ventus

of course this is in case we have more then one playable character, so is up to nomura   we can only speak.... and rise the hype of the game that never was.

is possible and i would like this to happen maybe with someone with affinity to that realm like riku and/or riku

meanwhile sora with mickey awaken ventus

of course this is in case we have more then one playable character, so is up to nomura   we can only speak.... and rise the hype of the game that never was.

Yes we can only hope Nomura could make something like this as a finale for the Xehanort saga

Not to mention Kairi has the courage to enter the Realm of Darkness without a weapon, so imagine her with one? This further shows that she's the perfect fit for a character to go on missions to the RoD, and would bring back Aqua with haste. I can foresee from there that they'd start to bond, both in character and battle. They'll probably learn from each other as well, but also more firmly appreciate who they are already. Of course, Aqua will likely seem like a mentor figure at first, for at least the duration of KHIII. 

 

If that sounds a little jumbled, I apologise.