Quote Originally Posted by Zombiesaur View Post
In days Roxas and (SPOILER)Xion are the only members who can kill heartless because it is explicetly stated that you need the keyblade in order to do so.
More specifically, one requires a keyblade to release the hearts consumed by said heartless. I guess we can presume destroying a heartless with any other weapon merely results in its temporary return to darkness or something of the sort.