Shadow of the Keybearer: A Nanoha/Kingdom Hearts idea

[Nekomata-sensei]

I'd suggest making Ranma one of the princesses of heart, partly for laughs, but also with the idea that some forces, such as Happosai and Genma, have already begun working towards the corruption, Saffron brought Ranma near the limit, but actually 'killing' Saffron with that attack was an accident, Ranma's aim had been guided by Akane's dehydrated form, it just happened to piece Saffron's heart and force a reincarnation cycle, Ranma just wanted to get by him in order to save Akane. Things are being manipulated in the background to try and drive Ranma over a psychological breaking point without actually killing him or trying to corrupt him too directly, which would cause him to rebel and ignore the person due to purity of heart.

It would be amusing if while in the Ranmaverse, the search for the princess of heart somehow gets out and various fiancees want to or are believed to be it for various reasons, and some believe it is Kasumi, only for it to turn out to be Ranma.

Another potential princess of heart could be Hiinata from Naruto.

[Muramasa]

Ugh... Ranma has nowhere near as pure a heart required to be a princess of heart. He's far too arrogant, insulting and at times just plain jealous. I'd sooner believe Kodachi was a candidate.


Edit: And yet another problem point... The Throne of Heroes only contains souls that the world (As in F/SN world only) recognizes as a hero... or a counter guardian. Roxas isn't a native of the world. He isn't recognized by the world. He is a completely foreign entity. The only possible means that Roxas could be connected to the throne is if someone deliberately manipulated (As in completely reprogrammed) the throne. That alone would require a lot of power...