User blog comment:Black Leg Sanji/Who was that masked man? or woman?/@comment-3097081-20110707101623

I also thought about it when I first saw the cover. Maybe an old Roger Pirates nakama, maybe Luffy's grandma (i.e. Garp's wife/lover/something), maybe some big important person in the One Piece world that we just haven't heard of yet, there are so many possibilities that it's way too hard to guess.