I've been reading through theories about the BHK and I was thinking, because he originates in Twilight Town, there is a possibility that the BHK is the other side of Sora's heart. If you remember, in Chain of Memories, when you had to fight Vexen for the last time. Before the battle, Sora said that he had never been here, but Vexen said he had, that the other side of his heart knew this town, but Sora didn't get it. What I'm trying to get at is, the BHK might have been made after Sora became a Heartless, the innocence trying to break free of the Darkness, and when it did, it never went back, and Sora's other side of his heart closed off, and that's why Twilight Town felt familiar.
