So in ch 906, we were given this ominous scene with Im visiting a giant straw hat that was preserved in mariejois. How will this hat come into play in the story?
Well I think its simple. The Hat is giant. Therefore whomever owned the hat must have been very big, a giant or perhaps a half giant(since I think the hat is a tiny bit small for a giant).
In any case, I think this hat has huge ties to Elbaf. One piece was a treasure left >presumably< from Joy Boy which was found by Roger and then by Luffy. Hence I think that the hat is most likely Joy Boy's(due to the parallel with Luffy) and that Joy Boy was either a giant of elbaf or half giant with ties to elbaf.
Elbaf is an island hyped since back in the very early days of OP, therefore it should be one of the most important islands we visit. Why? Because of it's ties to Joy Boy, the hat, and the ancient kingdom.
I think that once we reach elbaf, we will learn at least a little bit about who Joy Boy really was and what the hat does. I also think that this is where Whitebeard hid the road poneglyph that was once in fishman island. Given that Elbaf is the strongest country, by hiding it in such a place, WB made certain that the pongelyph and One Piece would never fall into the wrong hands, even after his death.
