The “Will of D.” is a mystery surrounding some people who have the initial “D.” in their names. Let’s see the possible meanings of D.:
1 – Dawn
It’s the most obvious one, a lot of people already thought about it since the first chapter of One Piece is called Romance dawn, and a lot of character have mentioned the “Dawn of the world” as the big event that the Straw Hats are supposed to bring in to the world.
Kozuki Toki said in her prophecy that someone will bring a new dawn.
2 – Devil
This hit me recently, the D. are “the natural enemy of gods”, what is the natural enemy of God? The Devil.
In One Piece the Celestial Dragons call themselves Gods and rules by pretending through the World Government that they are the good guys that takes down the evil pirates. But we know that in reality they are doing the most evil stuff hidden in the shadows, so it seems very fair for people like that calling themselves God that the one who can take them down would be the “Devils” or “Demons”.
There have been a lot of time where Luffy has been called a Demon in One Piece, and we know he doesn’t want at all to be a hero, so him taking down the so called “Gods” by being considered the “Devil” seems really fits.