Monkey D. Dragon

Monkey D. Dragon is the father of Portgas D. Ace and Monkey D. Luffy and the son of Monkey D. Garp. He is the infamous Revolutionary leader and has been giving the world government a hard time, he is the World Government's greatest enemy and is the most dangerous and most wanted man in the world.

Appearance
He is often seen in a long green cloak and recently he wears the clothes of a revolutionary. He has, what resembles, tribal tattoos on the left side of his face and spiky black hair with a widow's peak hairstyle. He is almost always seen with a sinister smile on his face.

Personality
His personality is mostly unknown due to the many mysteries surrounding him, save for an apparent love for freedom and belief in fate, which are traits of a D. Unlike other members of his family, or D's for that matter, he looks stern and serious, though in all his appearances so far, he wears a smug grin. He speaks as though he is a mystic of sorts. He didn't like to speak or be asked about his past. He also has a strange habit to always look toward East Blue when he is "feeling" the wind. His revolutionary comrade Emporio Ivankov attributes this to his instincts, having left Ace and Luffy in East Blue. Iva also says that Luffy's will to live and his phenomenal strength only help solidify the idea that he is Dragon's son, implying that Dragon has similar willpower and strength.

Revolutionaries
Emporio Ivankov, being the former queen of Kamabakka Kingdom, is one of Dragon's comrades and one of the commanders of his revolutionary army. Ivankov apparently understands Dragon's habit of looking at the direction of East Blue whenever the winds blow, as though homesick.

Enemies
Due to the fact that he is the leader and main center of the largest anti-government organization in the world he has been dubbed the most dangerous and wanted man by the World Government. As stated by Robin many people and organizations (especially pirates) would try to steer clear of disrupting the World Government and drawing attention to themselves, although the organization which is lead by Monkey D. Dragon does the exact opposite. Although many people call him a revolutionary the World Government feels that his ideals and goals can collapse the strength and justice which is known as the World Government. So far it seems the World Government is the only known enemy of Dragon.

Monkey D. Garp
Dragon is the son of the well known vice-admiral Monkey D. Garp. No direct interaction has been seen between the two, however, Garp was casual towards telling Luffy about Dragon's role while he picked his nose. He even laughed when he realized he shouldn't be telling people that kind of information. It does seems to be there is some sort of interaction between the two, as Garp stated, that the reason why Dragon was in Loguetown, was to see Luffy set off to the Grand Line.

Portgas
Portgas is the surname and only known name of Dragon's lover, and Ace's mother. It is unknown whether she also gave birth to Luffy. Little is known about the relationship between her and Dragon, and it is unknown whether they were married or not. The controversy over the name discrepancy between Luffy and Ace (as to their relation) was resolved when Ace's true name was revealed to be indeed Monkey D. Ace, but that he had changed it by taking up his mother's, whom he had memories, respect, and almost without a doubt, love for. Meanwhile, he has no memories of his father. Rather than stating abandonment, or something similar, Ace chooses the term memories, insinuating that Dragon was around, at least for a little while, but never made an impression upon Ace as a child.

Portgas D. Ace
Most recently has it been revealed by Ace that he took the name Portgas after his mother, claiming that his relation to Dragon is only through the blood he has running in his veins. While captured in Impel Down talking to his grandfather Monkey D. Garp, while chained in his jail cell he shows a disliking towards his father and claims that Whitebeard is the only father he has.

Monkey D. Luffy
Luffy is Dragon's son. Like his father Garp, he seems to hold high expectations for Luffy and although has not introduced himself to him, seems to support his son's actions so far. He also appeared in Loguetown to see Luffy off to the Grand Line and stopped Smoker from capturing Luffy. This shows that he has some care for Luffy's well being.

Other
No mother has been named for Dragon, however both were left as "?" in the supplement issue The Grand Line Times. As a carrier of the Will of D he may also be related to other D's.

Abilities and Powers
Little has been revealed about Monkey D. Dragon's abilities; however, he is the leader of the Revolutionaries and has full command of the organization.

Emporio Ivankov also noted that the World Government's decision to capture Ace will prove problematic to them as they'll have to deal with both him and Whitebeard. This would imply that Dragon himself is a very powerful person. He does appear to have some kind of affinity to weather as it is implied he started the tornado and lightning storm in Loguetown and has been said to "feel" the wind.

Past Story
Dragon's history remains mostly a mystery, thus it is unclear why Luffy was left to be brought up by his grandfather Garp instead of himself. At some point he began the Revolutionary movement becoming its leader and his ideals began to slowly spread throughout the world. One by one countries slowly began to support him, though sometimes through war.

The little known history on him is that six years ago, in the Council of the Kings in Mariejois, the purpose was to discuss his revolutionary movement and his ideals that were threatening the World Government. Thalassa Lucas showed the picture of him. It was then he revealed that Dragon was currently no real threat, but would become so, in 5-6 years or so, if not dealt with.

Loguetown Arc
His first appearance was during the Loguetown Arc where he saved his son Monkey D. Luffy from Captain Smoker. At that moment a gust of wind passed through Loguetown blowing Luffy, Smoker and Buggy the Clown away. It's not known if he controlled the wind that blew off the marines at this point, but in the manga he did say the word "Storm" as the wind passed by and seemed untouched by it.

Post Enies Lobby Arc
While visiting Luffy, Garp let slip that Dragon was Luffy's father in a casual conversation with him. The reaction of those present was of dire shock. It was then revealed to Luffy just who his father was by Robin.

Robin stated that he was the top of the revolutionary army and has spread his ideals to every nation and kingdom, causing many of them to fall into his hands. He manages to stir rebellion around the world and has successfully pushed the world towards civil war. His actions greatly anger the World Government and he is considered the most dangerous man in the world. Until that moment, no one had known anything about Dragon, not even his full name.

Current Events
He has since reappeared again on Paladego. Seeing Luffy's new bounty one of his men was about to tell him that Luffy was Vice Admiral Garp's grandson when Dragon stops him and says he will stay in the wind for a while. He walks out into the castle's balcony where he remarked that the true nature of the world will be answered and he will meet Luffy again.

Later, after Emporio Ivankov's debut, Luffy found out that he was one of Dragon's nakama, whereas Iva was surprised to know that Luffy was Dragon's son. This shows that Dragon did not tell much about his family to Iva. However as he came to understand the situation Iva decided to help Luffy to find Ace within Impel Down as he assumed Ace to be Dragon's son as well. Iva comes to the conclusion that the World Government would be hard-pressed to deal with Whitebeard and Dragon at the same time, implying that Dragon is a very powerful person.

Trivia

 * Dragon has been the center of several myths among fans.
 * Whether it is a foreshadowing on Oda's part or a coincidence, Luffy appeared in the short Mugiwara Theatre - Monster Time as a dragon years before he was revealed to be Dragon's son.