That photo isn't mine but i do own 4, 2 sealed and 2 loose. the SQ watch is pretty much the Rolex of castlevania items lol
i don't know if that's the rarest though. there are a lot of Japan-only items that are extremely hard to come by. off the top of my head, some plush dolls, promotional items here n there, soundtracks.. i own several official whips that used to be sold on Konami's website back in the early 2000s
I own a very very old legit Belmont's Revenge poster board, which only a handful of them were made. it's made out of wood