User blog comment:Luffayking12/Shanks and Monkey D. Dragon/@comment-5167400-20120605080712

..

Monkey D Dragon = Luffy's Father... Shanks = Once a Cabinboy of Gol D Roger, "the man who own arm" to save Luffy from the giant monster fish... But I think he tells Whitebeard that he bid his arm for a reason of the creating a second era of pirate. This was discuss during the duel between Edward Newgate and Shanks.