(Pending detail — what “King of the World” actually means, and whether it points at the world’s true (hidden) ruler, is forward.)
Earliest known caller
(Not researched.)
Why this matters
Rocks alone among the great pirates is given an ambition that overshoots the Pirate King’s: not the freedom-treasure One Piece, but rulership of the world — the same seat the Empty Throne guards. Pairs a “D.” bearer with a world-throne ambition decades before the Im/Void-Century layer.