I, personally, thinkg BHK is a shell like the enigmatic man. Because in KH sora lost his heart for a while and became a heartless, so his heart was casted off from the body (but kairi came back into th ep icture and brought him back) so I think that is why he looks like him and is looking for hi, know's namine and so on. I apologize if someoen has posted this already. I've been out of the loop for a while! Thanks for reading though!