His tattoo isn’t a random piece of art, it’s actually a Shandia tattoo. Outside of Dragon himself, there are only two major characters with similar tattoos in the One Piece universe: Calgara and Wiper. Bear in mind that Wiper’s and Calgara’s tattoo are quite different, despite them coming from the same tribe.
I think Dragon’s tattoo refers to his ancestors. He is of Shandia origin.
There are strong chances that Dragon learned what did happen during the Void Century and he also probably learned the origin of the D. Clan at some point. He learned – a part of – the story, was disgusted by what the Twenty Kindgoms presumly did to his ancestors and decided to mark his face permanently before chosing to fight back and take revenge for his people.
It’s not a popular theory, but many people think the D. and the winged people are somewhat related. It’s mostly because of the cover of the volume 27.
We see Luffy with a pair of Shandia wings, winking at the reader. On its own, this hint is light, we agree, but there are other hints in the manga that the D. and the winged people are related.
It’s not commonly brought up, but Oda also drawn Luffy as a Shandia or using Shandia kind of tools in color spreads quite a few times, while the other members of the crew were depicted normally.
The last point is important since Luffy has been drawn as a Samurai, a Knight or many things in color spreads, but in those color spreads the other members of the crews were often depicted in the same way as him. On the color spreads from the chapters 175, 431 and 352, Luffy is the only one depicted as a Shandia or a native indian. We know for a fact that Oda like to use Color Spreads to hide small details and while it could mean nothing, I think it’s still a point to consider.
*Theory by demise000
