Four Emperors



The Yonkou (四皇, Yonkō), literally Four Emperors, are the 4 great pirates who rule the second half of the Grand Line (known as 'the New World').

They are one of the 3 great powers, the other being the Shichibukai and Marines and live quite literally as though they are Emperors, doing mostly as they please. For the World Government, these are the greatest pirate threats in the world. It is only the combined efforts of the Marines and the Shichibukai that keeps their power in check.

The four emperors themselves are not united together as one group like the Shichibukai and follow their own individual paths, but the possibility that two or more of the Yonkou could form an alliance is a great worry to the World Government. For that reason, the World Government attempts unsuccessfully to prevent a meeting between Red-Haired Shanks and Whitebeard, at one point in the series, fearing the two emperors may unite together creating a stronger threat.

Hypothetically, the three powers are equal in strength. They however are not an organization working together like the others, and the emperors may consider each other as an enemy. While Shichibukai pirates consider only the captain's power, a large part of an emperor's power comes from their crew. For example, Portgas D. Ace, commander of Whitebeard's second division's, defeat was enough to guarantee the title of a Shichibukai.

History
Much of the history of the Yonkou is unknown.

The first of the Yonkou to be introduced was Shanks who visited Luffy's hometown ten years ago, though it was unknown that the Yonkou existed at this point of time, although it is reasonable to assume they did as this was the around the time the Shichibukai orginization was being formed. The second was Whitebeard, the only man to tie in a fight with Roger and was later announced the strongest pirate in the world upon his death. Some of the Shichibukai were rivals to the Yonkou in the past; Shanks was a rival to Mihawk and Kaidou to Gecko Moria.

Shanks and Whitebeard are both familiar to the old days of piracy, before Roger's death 22 years ago, though it is currently unknown if the other two Yonkou are from the old days of piracy.

One of the more familiar movements of the Yonkou's history were to acquire strong fleets, including ships and elite crewmen. All Yonkou traveled to the New World at some point in their past, where they are currently locked in stalemate, unable to progress any further into the Grand Line. This is a product of the combined efforts of both the Marines and Shichibukai, as well as the presence of each other Yonkou in the Grand Line.

Until recently, the World Government has been fine with the world powers remaining as they are, with the Yonkou stuck in a deadlock situation as this allowed the world to remain stable. With the absence of Crocodile, defeated at the hands of the Straw Hat Pirates, they were alarmed with two of the Yonkou, Shanks and Whitebeard, arranged to meet each other. Later with Enies Lobby in ruins, the Marines saw another defeat in the New World when a blockade failed to prevent the two meeting.

Fearing the two crews forming an alliance, the World Government has resulted in laying in wait to see what happens. Shanks believes the days of Whitebeard as the top pirate are coming to end, warning him of the era to come. With Blackbeard aka Marshall D. Teach now making his move to the top, the pair are last seen clashing weapons. It has recently been stated that the Shichibukai are preparing to battle the Whitebeard Pirates.

The shift in the Balance
So far two incidents committed by the Straw Hat Pirates have seemed to disrupt this balance in favour of the Emperors:


 * When Crocodile of the Shichibukai was defeated, Shanks managed to make contact with Whitebeard.


 * The incidents at Enies Lobby shifted the balance against the Marines. Whether it directly affected events playing out in 'the New World' is unknown. Soon, after this incident, Whitebeard and Shanks broke through attempts to halt both Emperors from seeing each other.

List of Pirate Emperors

 * 1) Shanks
 * 2) Whitebeard
 * 3) Kaidou
 * 4) Unknown