It hit me before I went to bed.
The D… stands for Davy!
Let's think about what's been said about Davy Jones:
1. Legendary Pirate. How many pirates have been called Legendary? The only other one I can recall is Roger.
2. Considering that the Davy Back fight is about obtaining the largest crew, and Davy was the leader of Pirate Island, Davy Jones would have the largest and most experienced crew on the Grand Line.
3. Davy Jones lives at the bottom of the sea, and has lived down there for centuries aboard his massive treasure ship.
4. Davy Jones was cursed by the devil, meaning he obviously ate a devil fruit.
5. Davy Jones revolutionized the world with his "Games", the same way all the other D's do.
6. Davy Jones keeps a great treasure in his locker.
This said, every D has probable cause to be connected to Davy Jones, or rather, his crew. If Davy Jones is still alive aboard a massive ship, it's possible that Jones is the immortal guardian of Raftel. Only those that carry his will or his legacy have any claim to being Pirate King. That's why Luffy's destiny is to be a pirate... because he's descended from Davy Jones, the first Pirate King.
So, Gol Davy Roger, Luffy Davy Monkey, Marshall Davy Teach, etc, etc. Only the Davys will prevail.
What do you guys think?