Pirate

A Pirate (海賊) in the world of One Piece is anyone who raises a Jolly Roger, whether they commit an act of piracy or not. This is not, however, usually enough to give anyone a bounty, but is enough to be arrested by the Marines. Mountain bandits are said to be the opposite of pirates. The two have not been known to get along with each other too well.

There are two types of pirates in One Piece, but the terms were only in the original Romance Dawn chapter. They have not been mentioned in the current version of One Piece and it is doubtful they still apply to it.

Types of Pirates
First mentioned in Romance Dawn V.1, the two main types of pirate are Peace Main (ピースメイン) and Morganeer (モーガニア). These terms were once again mentioned in Romance Dawn V.2, and in Wanted! Chapter 5, however they are not mentioned in One Piece itself. This is largely due to the fact most pirates are a combination of both peace main and morganeer. Even the final version, a certain amount of pirates display these original concepts, though the actual terms are no longer used.

There is also another kind of pirates, known as "rookie" pirates, which the Straw Hats fell under before the timeskip. All of the Eleven Supernovas and the Bellamy Pirates from two years ago, along with the Caribou Pirates of the current timeline are considered to be rookies. It is unknown what qualifies a person or crew to be a rookie though the word generally means that they are new-comers or new recruits. This may mean that these pirates have only been active for a short time and are relatively new.

Female pirates, though unusual, are by no means rare. The reason for this may stem from the old superstition that women on a ship is bad luck, but also possibly due to the fact that pirates are unsavory characters. More often than not, the women tend to be the captains of their crew, with certain exceptions, like with the Straw Hat Pirates, the Foxy Pirates, the Kuja Pirates, and the Whitebeard Pirates.

Peace Main
Described in Romance Dawn Version 1, a peace main is a pirate who goes on adventures and doesn't really care about amassing treasure or fighting other pirates. Luffy, Brook, Shanks, and Whitebeard are all good examples of pirates based on the old peace mains (along with their respective crews) from Romance Dawn. That is not to say that they will not steal treasure from others if it is there and the chance is open, but their primary goal is usually not to own it and greed is generally not their motivation. More often than not, a peace main pirate sees his or her own crew as their most valuable treasure.

Some pirates start out as peace mains but may have a life changing experience, possibly a great loss or general corruption over time, and become more like a morganeer. The best example of this is Crocodile, who is said to have been very much like Luffy in his youth, or Gekko Moriah, who stated that he was exactly like Luffy until he lost his crew in the New World. Peace mains have been described in Wanted! Chapter 5 as a pirate that goes on adventures funding themselves on the spoils of battles with morganeers.

Morganeer
The morganeer fight for treasure and personal gain. They are greedy and love to fight just to cause other people pain and misery. Most of the other pirates Luffy and his crew meet are morganeers. Luffy dislikes them and only wants to recruit peace main pirates. Even in the beginning storyline, most One Piece villains are based on the concept of morganeer pirates, such as Buggy, Don Krieg and Kuro. The peace main pirates however, only steal from them, so it is safe to say that the relations between the two aren't the best.

Morganeer pirates don't see their crew as a valuable asset to them and will easily kill them for opposing them as demonstrated by Don Krieg. Kuro also didn't think twice about slaughtering his own men, and the only sympathy he showed towards his crew was because Luffy stopped him so that they would not have to suffer. Luffy was shocked to see Kuro slashing his own men half to death. Also, many of the morganeer type pirates shown in One Piece don't dream at all, and if they do, it is about achieving world domination or something along the lines of that. There are only a few morganeer pirate captains who have a good relationship with their crew like Vander Decken IX, Arlong, Buggy, and even Blackbeard.

The Four Blues
Generally outside of the Grand Line, most pirates operating in the blues are considerably weaker than those inside. Often, they are left untouched by the Marines because their attention is drawn towards the Grand Line rather then the East, West, North, or South Blue oceans.

That is not to say that they do not have their share of villainous pirates, as even in the weakest of the blues, the East Blue, powerful men like Don Krieg and Arlong were found. Generally, few people in the four blues have access to Devil Fruits or general knowledge of them. Most pirates seen before the Straw Hat Pirates entered the Grand Line fight by using of some form of weapon, the only exception being Buggy (whose Devil Fruit was found by the Roger Pirates, in the Grand Line).

The Grand Line
While there are individual pirate crews roaming the Grand Line, the more powerful pirates reside in this sea. These are namely the Shichibukai and the Yonko.

Generally, the weaker pirates are often weeded out by the Marines or Shichibukai before they can get any further. The unfortunate ones don't even make it to their first island due to a lack of understanding on how the weather works on the Grand Line. The Grand Line is where you're most likely to see Devil Fruit users, both in and out of pirate crews.

In the second half of the Grand Line the most powerful pirates are the Yonko. The second half of the Grand Line is their playground and it forms a rather dangerously balanced part of the One Piece world.

Due to the Red Line, the Grand Line is separated into two segments. The first half is known as Paradise where the second half is called New World.

The Pirate King
The Pirate King (海賊王) is the strongest pirate alive and owner of the legendary treasure that was later dubbed as "One Piece".

The term "Pirate King" was originally a simple nickname for Gol D. Roger to distinguish himself among swashbucklers. Upon Roger's execution, the name was romanticized by the people of the One Piece world into an actual title, much in the same way One Piece itself was simply "Roger's treasure" until the Pirate King's death. In the English manga and anime, "Pirate King" clearly marks this distinguishment; although Gol D. Roger was Pirate King, Monkey D. Luffy seeks to become the new Pirate King 22 years later.

Before his death, Pirate King Gol D. Roger hid One Piece. It was rumored to be located at Raftel, the island at the end of the Grand Line. The frenzy over discovering and owning such a massive treasure sparked the "Great Age of Pirates". Until One Piece has been claimed, there will be no current Pirate King.

Until his death, the closest person to becoming the Pirate King was Whitebeard. Many people who had met Luffy, such as Coby and Helmeppo, believe that he will be the Pirate King; Kokoro also addressed Luffy as the Pirate King and Shakuyaku has stated that both she and Silvers Rayleigh were rooting for Luffy to achieve this goal.

The reasons for a person wanting to be the Pirate King vary, Gekko Moriah and Blackbeard wish to acquire it for the power and influence the title would come with, while others like the Yonko are considered candidates for it because they're extremely powerful and very close to it, but the two shown so far appear to not have any interest in it except for Blackbeard who later replaced Whitebeard as one of the Yonko. Still others like Luffy and Crocodile (prior to the event that caused him to let go of it) wish to become the Pirate King because it is a dream of theirs. Luffy (and Crocodile in his youth) seem to want it for the adventures that are involved with becoming the Pirate King. The Pirate King is said to be the ruler of the sea (Enel asks Luffy about the country the Pirate King rules [after Luffy says that he will be one], Luffy answers this by saying that the Pirate King is the king of the sea, Enel then says that it would be a very interesting title).

When talking to Silvers Rayleigh, Luffy said that the Pirate King is the person with the most freedom on the sea. After hearing this Rayleigh smiled to himself, possibly because Roger himself had also stated this being his primary value.

Before the Golden Age
Pirates have long been a part of the way of life in the One Piece world. The oldest known group of pirates mentioned were the ones under Dorry and Brogy from more than 100 years ago. However, despite pirates existing back then, none of them were known to be noteworthy enough to shake the world.

Then all that changed with the arrival of the great pirate Gol D. Roger (and others like Edward Newgate and Shiki). Roger set about to do what no one had done before - conquer the Grand Line. He succeeded and in doing so made his way to Raftel and left behind something somewhere in the world, his most prized possession, One Piece. Roger brought about an air of romance about being a pirate and upon his death his final words sent others to sea to become a pirate. Things would never be the same again.

The Golden Age of Piracy
The death of Roger sent many pirates to the Grand Line, hoping to find his treasure and become the Pirate King. However, with the new wave of pirates came a new change that even Whitebeard noted.

Over the next few decades the old figures of the pre-pirate age began to disappear due to the span of time. This left fewer and fewer people aware of the days of piracy before Roger's death. Many old values shared by the pirates of the pre-pirate age slowly began to die. Even once commonly sung songs like Binks' sake have begun to fade out of memory, save from the minds of those who still remember the olden days of piracy (such as those Brook and Shanks). Although, newer pirates still adopt these values some completely go in a different direction, the most prominent is Doflamingo who speaks of a New Age where pirates should stop dreaming.

With the Great Age of Piracy spiraling out of control, the World Government became deeply concerned. In response, they created the Shichibukai and sent them out to kill other pirates. The World Government also allowed themselves to easily be manipulated by Spandam into a machination to acquire Pluton to combat the increase in pirate activity, unaware that he had ulterior motives in mind.

The New Age
At the start of the storyline, the New Age was fast approaching. This New Age of Piracy was brought upon by changes in the world. Various characters who have mentioned it either spoke of a world on the verge of chaos, or a great age where pirates no longer chase their dreams.

Related to this oncoming age in particular was the capture of Whitebeard's 2nd division commander Fire Fist Ace by the Marines. This significant action resulted in the Shichibukai and Marines assembling together in preparation for a war against Whitebeard himself. During the war, Ace was killed and Whitebeard attempted to take down Marineford. Finally Whitebeard, who held the Age of Pirates together, died, leaving his vast terroritories up for grabs by other pirates in the New World. It may also be noted that after Blackbeard took Whitebeard's Gura Gura no Mi powers, he said that this age will be "his age" shouting aloud for everyone in Marineford and Sabaody Archipelago (viewing via visual Den Den Mushi) to hear. The "New Age" is a phrase used to emphasize the fact that the world is changing, and different pirates obviously have different ideas about what the coming age will be like. Bellamy believed the coming age would be an age without dreams, while Blackbeard believes just the opposite.

With the start of the New Age, a new wave of pirates went to sea looking for One Piece, having heard Whitebeard confirm its existence. A number of pirates from the previous era escaped Level 6, and it was noted by X Drake that a new age also means that the Marines themselves now must change with this. However the exact direction this new era will take is still as of yet unknown.

It has been hinted in the series, though, that it is going farther and farther out of the government's hands, with pirates everywhere, all of which appear to be less and less mindful of the government. The people of Luffy's hometown note that "for the past few days we've been seeing pirate ships on the coast, we can't even sleep".

Translation and Dub Issues
There are a few notes about a name of a pirate crew to consider:
 * Despite some of the crews names such as the Red Hair Pirates, most of the members won't have anything in common with their crews name (i.e. they won't be red haired), Red-Haired would be a direct translation as plurals don't exist in the Japanese language. The crews are almost always named after their captain, in this case "Red-Haired Shanks" and from indirect translation his crew would be "Red-Hair's Pirate Crew".
 * Kaizoku though is the Japanese word for "pirate" translates literally to "sea thief" or "sea robber". "Kaizoku-dan" itself does not literally mean "pirate crew" but rather would translate to "band of pirates". Ultimately, a pirate crew should be written down as (for example) "Red Hair's band of sea thieves", to an English speaker, this name makes less sense than "Red Haired pirate crew". It is common for English speakers to use "pirate crew" rather than "band of sea thieves" as it makes more sense to other English speakers and has an easier ring to the name, similarly how "Whitebeard" is never called "White facial hair" despite what his name is trying to say.

Trivia

 * Privateers and pirates are often grouped together as one and the same. The only real difference was that privateers can be consider hired "pirates", who were contracted to work for their governments against other nations on the seas, and were generally allowed to do anything they wanted so long as they did not attack their own countries ships. Pirates however, work for no one and worked on their own accords. In One Piece, the Shichibukai are based on "Privateers", however the Straw Hats themselves have done actions that would fall into this classification as well; such as helping Alabasta against Crocodile (originally Nami only agreed to protect Vivi for a price).
 * The "Age of Pirates" established by Gol D. Roger, is based on the real world's own golden age of piracy.
 * "Pirate King" was a real historical title used by powerful Japanese pirates who operated in the Inland Sea.