Summary
There are plenty of mysteries circling around the manga and anime epicOne Piece. What is happening to the World Government? What happened during the Void Century? Who created the Ancient Weapons?
Of all these mysteries, perhaps the strangest one is what the D in Monkey D. Luffy’s name means. Luffy isn’t the only one with the D initial, either, but he’s certainly the most prominent. As the series enters its final arc, one that will likely take months, if not years, to complete, we might have to wait until we get a firm answer, but here’s everything we know about the initial so far.

What Does The ‘D’ In Monkey D. Luffy Mean?
It’s More Than A Middle Name
First thing first, we need to dive into the history of the initial. According to Imu, an enigmatic and largely unknown secret ruler of the World Government, the use of a ‘D’ signaled that an individual was an enemy of the First Twenty, also known as the Creators. These people were twenty rulers who created a united army called the Alliance during the Void Century, which would eventually become the families of the Celestial Dragons, and their Alliance became the World Government.
Since then, those with the D initials are said to have inherited the ‘Will of D.’, and they are often at the center of pivotal events that have major implications on the workings of the world. Those with the Will of D are also said to belong to the Clan of D, though connections are loose and do not mean a family connection.

For example, Luffy, his father Dragon, and grandfather Garp all share the initial and are all related, but Marshall D. Teach also has the initial and does not bear a blood relation to Luffy. However, it does seem to follow family lines to an extent since Portgas D. Ace and both his parents have the initial as well.
In a flashback sequenceinvolving a young Trafalgar D. Lawand Donquixote Rosinante, also known as Corazon, explains a little bit of the meaning of the initial, making Trafalgar one of the few people of the world that has any knowledge of the meaning of the initial. During this flashback, Rosinante called the Clan of D the “Natural Enemy of God”, which can be interpreted in a few ways.

It could mean that the people with the D. initial are enemies of the Celestial Dragons, especially since they’re often referred to as Gods. It could also mean they are enemies of Inu, though it has yet to be confirmed.
What Else Do We Know About The Will Of D?
There’s A Lot Of Little Details
Those with the Will of D seem to have a few common features that mark them as members of the Clan of D. Those with the D initial are particularly fearless in battle and can survive injuries that verge on the impossible, though they can still die. Two notable deaths include Ace and Gol. D. Roger, though there’s a common factor there too, past the fact that they’re directly related.
People with the Will of D seem to smile in the face of death. This has been seen around seven times in the series, though the person doesn’t have to die for it to be counted, just if they think they’re about to die.
Gol D. Roger allegedly smiled right before he was executed, and Trafalgar D. Law smiled when Donquixote Doflamingo had a gun pointed at him and was about to kill him. More recently, Monkey D. Garp was laughing when he was speared by Kuzan by an ice blade.
We also know who the first person to take on the initial, and that is the ancestor of Nefertari Vivi, Nefertari D. Lili, an ancient queen of the Alabasta Kingdom during the Void Century. This makes the Nefertari family part of the D lineage, as they abstained from joining the World Government and Celestial Dragons despite being a part of the First Twenty.
So, How Is This All Related?
So here’s the deal with the Will of D. Gol D. Roger allegedly learned the truth of the initial when he finally landed on Laugh Tale, as Kozuki Oden stated that he and the rest of the Roger Pirates all knew the meaning. Whitebeard too knew the meaning of the initial and the implications that it had on the world.
All this means that once Luffy and the Straw Hat Pirates make it to Laugh Tale they too will learn the significance of the initial. While Luffy might not care so much about the meaning,Nico Robin and most of the rest of the crewwill understand the implications of the name and what impact it will have on the world.
There’s a not insignificant chance that the One Piece is the understanding of what the name is the One Piece treasure itself, and Gol D. Roger sent the pirates of the world after it in the hopes that another member of the Will of D. will be able to enact on it.
Which One Piece Characters Have ‘D’ In Their Name?
There are 15 characters that are confirmed to have the D initial, though there are likely plenty more that we either have never met in the series or that are not even aware that they have the initial. Here’s everyone we know for certain who has inherited the Will of D.