The first time he appeared in the Logue Town, when he helped Luffy is attacked by Smoker.
The sequence of appearance:
1. 22 years ago (1500 AOS) he witnessed the execution of the King of Pirate Gol D. Roger. (there are no tattoos on his face)
2. 10 years ago (1512 AOS) he came to the goa kingdom and met with sabo (Luffy's foster brother) who were injured because he was attacked by the royal army of goa kingdom.
3. 6 years ago (1516 AOS) the King of illusia, Thalassa Lucas said that Dragon like a "thorn in the flesh" which is very dangerous.
At random times, he spoke with Ivankov. It is not known when.
4. Time is now (1522 AOS) He appeared in Loguetown. Saved Luffy from Smoker attacking.
He appeared again in Baltigo (headquarters of the revolutionary army)
Dragon is a very mysterious person, no single person who knows his strengths. He's moving in the shadows.
But in volume 45 Garp divulge his identity inadvertently to many people in the Water 7.
Predictions and theories about the dragon
1. What possessed the power of dragon?
the fact that always follow dragon is where he is, always seen any wind.
Looks like a wind always follow Dragon wherever located. Sometimes nature is also "react" to the devil fruit ability.
What you remember when the Drum Kingdom is not snowing at all when Portgas D Ace wanders in there?
Could Dragon is wind logia user? very likely that he is a wind logia devil fruit eaters, but in addition to predictions about the wind logia he might eat the another devil fruit. What you remember ability "Marco Phoenix"?
It's true, I think Dragon is a demon fruit eater mytichal Zoan hebi hebi no mi Dragon-type. The dragon in the legend EAST (aka Shen Long) is known ruler of winds and clouds. He can cause severe weather. is that true? remember this is just my prediction.
Dragon sketch form when using the power of the devil mytichal Zoan dragon fruit.
2. How to explain events in Loguetown and in GREY TERMINAL?
This is just my prediction ...
In Loguetown, he saw a bounty poster for his child. when he saw Luffy will be executed by the buggy, he was soon transformed into a dragon to summon a cloud. Calling this process was not directly bring in storms. but must start by calling the storm clouds in advance. Elsewhere Nami felt an abnormal decrease in air pressure. What you remember when the store owner's aunt confusion when Nami asked umbrella, because the signs of Hurricane did not exist at all before. STORM IS NOT NATURAL. But still, Nami could have predicted the extraordinary.
Ultimately come down to the beginning LIGHTNING storms striking the buggy and Luffy. Dragon deed Was it? NOT! Remember He's just calling the storm clouds, he could not control lightning, which is one of the "effect" of the storm! LIGHTNING EVENT SO THAT DISCRETION IS PURE HEAVEN.
Then there are more events "strong breeze" that hit the entire Loguetown. Who threw Luffy to escape from the grip Smoker.
Dragon deed Was it? This time I answered YES! Scope of power of the wind is blowing Shen Long ..! So the Dragon makes the wind blowing hard with the power of his Dragon. Then will come the question? If the gusts of wind that acts Dragon, why was he not wearing the form of the Dragon? The point that was, How it works Mythical Zoan somewhat unusual, because in addition to the ability Zoan he also has the ability "PARAMECIA" at once. Zoan mytichal very rare ability. Transformed into birds and fly a Phoenix Zoan strength, and recover with the eternal flame is the ability Paramecia. What MARCO always and always changing so Phoenix will recovery time?
A time when his wings just fire up the issue but its still a human face. Because there is no such requirement. I think the wind to blow away the Dragon does not need to wear a half-human half-animal beings his Zoan ability.
Then there was another massive explosion in Grey Terminal. what is this deed dragon again? that's true ..! I think this is a deed Dragon again! IN the panel before the explosion that caused the trail was no wind blowing softly. Obviously Ursus SHOCK or Iva Wink HELL can not give such effect is not it? Who else if not Dragon do? Moreover, turbulence is similar to the wind gusts above Loguetown.
3. is it true that Sabo was saved by a Dragon?
I am a person who believes that Sabo was still alive. Why? Because death is very doubtful, and the fact that the Dragon brings "someone" who was wounded in chapter 589 to ship in the village Shimoshiki.
I still hope that this guy is really sabo.
What do you think? Dragon and RA is still very mysterious. In addition to those activities that blatantly destroyed the kingdoms under a World Government one by one. Many say that the Dragon knows the contents Poneglyph and history 700 years ago? but I think not. Dragon Revolutionary Movement purely because they see the "real" depravity in the world and among the aristocracy. Remember Wapol? how arbitrary his authority he? Remember that executes Lynell King Monbran Norland arbitrarily? Do not forget to also savagery Tenryuubito? the latest outrage and the Kingdom of GOA? Although there is also a very wise like King Cobra in Arabasta, does not eliminate the fact outrage "MOST" Kings of the world. This savagery was the moving force of the revolution throughout the world, savagery is what makes RA "seem" more and more large and dangerous.