The captains who formed the alliance are theoretically equal in status, and cannot give each other orders. They may have limited control over each other's crews, but the highest authority still lies with the respective captains.
In a situation where one of the captains gets captured, the other can take charge of their remaining subordinates.
Goals and Benefits
An alliance is usually formed with the purpose of reaching a specific, mutual goal. It may be something that neither crew could accomplish on their own, such as defeating a powerful enemy or finding a lost treasure.
A common problem with pirate alliances is betrayal; when one captain sees no more use of the other, it results in treason in order to reduce the needs to share glory. Also, due to their mutual goal being the only thing that binds them together, they usually have little to no respect for members of the allied crews, leading to one insulting the other behind their backs or even attacking them over perceived threats. However, if the allied groups have enough respect for each other, then these issues can be avoided and their alliance could either become permanent or they can part ways on good terms when their goal is reached.
For the Seven Warlords of the Sea, forming an alliance essentially means forfeiting their status, as the World Government does not permit such affiliations with criminals. Also, due to their sheer power, the World Government dreaded the possibility that one of the Four Emperors would forge an alliance with each other.
Another problem is that an attempt to even establish an alliance between captains and their respective crews can result in conflict if it fails, like when Shiki and the Golden Lion Pirates proposed an alliance with Gol D. Roger and the Roger Pirates which resulted in the Battle of Edd War when Roger rejected Shiki's offer.
List of Alliances
Buggy and Alvida Alliance
- Further information: Buggy and Alvida Alliance
The Buggy and Alvida Pirate Alliance is an alliance formed by the pirate bands known as the Buggy Pirates and the Alvida Pirates (although only its captain remained from them) and led by the leaders of the groups, Captains Buggy and Alvida. They teamed up in order to defeat a common enemy, Monkey D. Luffy, and remain allied even after this failure, to find Captain John's lost treasure. As Buggy has became a Warlord of the Sea during the time-skip, he is forbidden to hold an alliance with Alvida as equals, though no action or knowledge is seen taken against both crews. It is possible that the alliance, now known as Buggy's Delivery, evolved into a fully integrated group instead.
- Further information: Saruyama Alliance
The Saruyama Alliance is an alliance that was formed between three pirate captains, Mont Blanc Cricket and his surrogate sons "Salvage King" Masira and his brother "Sonar King" Shoujou. It composes of two pirate crews led by the brothers: the Masira Pirates (マシラ海賊団 Mashira Kaizokudan?) and Shoujou Pirates (ショウジョウ海賊団 Shōjō Kaizokudan?). Unlike many other alliances seen, they are extremely loyal to each other to the end, akin to a family. They work together to salvage evidence for the lost Sky Island, in order to prove Cricket's ancestor, Mont Blanc Noland, was not a liar. Their alliance continued in search for new dreams, and are currently looking for the 'Island of Dreams', Nakrowa.
- Further information: Ninja-Pirate-Mink-Samurai Alliance
On Punk Hazard, the Heart Pirates and Straw Hat Pirates, two crews from The Worst Generation, formed an alliance. The respective captains, Trafalgar D. Water Law and Monkey D. Luffy, teamed up with the sole purpose of overthrowing Kaidou of the Four Emperors. This alliance was proposed by Law, who, at the time, was still a Warlord of the Sea.
However, the true reason for the alliance was to destroy the SMILE Factory that belonged to another Warlord, Donquixote Doflamingo, who allied with Kaidou; what Law did not inform Luffy at the time was that he intended to kill Doflamingo and destroy the entire Donquixote Pirates to avenge the death of Donquixote Rosinante. The alliance was placed in the newspaper the next day and all around the world people reacted in shock upon learning of it. Kin'emon and Momonosuke joined the group hoping to save Kanjuro. On Dressrosa, Law called off the alliance while facing Doflamingo but after being captured Luffy forced him back into it stating that it was his choice and not Law's, much to Law's irritation, but reluctant acceptance.
As Law is a Shichibukai, he was forbidden from allying with pirates who are not allied with the Government, and as such his title is revoked. Although they have yet to achieve their promised goal of defeating Kaidou, the alliance has succeeded Law's quest to defeat Doflamingo. the results of their victory over Doflamingo were reported on a global scale. This alliance is notable as the two captains of this alliance Monkey D. Luffy & Trafalgar D. Water Law are both carriers of D.
Upon reuniting with the other half of the Straw Hat Pirates on Zou, the alliance learned that the samurai of the Kozuki Family were fighting against Kaidou as well, who is currently occupying Wano Country with the shogun there. They requested to form an additional branch to the Heart-Straw Hat Alliance to take down the Emperor, and Luffy accepted, forming an alliance between the pirates, the Kozuki Family, and the Mink Tribe. Luffy dubbed this group as the Ninja-Pirate-Mink-Samurai Alliance.
Beasts and Big Mom Pirate Alliance
Two of the Four Emperors, Kaidou of the Beasts Pirates and Charlotte Linlin of the Big Mom Pirates, formed an alliance between their crews after their duel on Onigashima. The two captains agreed that they would return to being enemies and resume trying to killing each other after they conquer the world. This alliance was proposed by Big Mom. For the New Onigashima Project, Kaidou and Big Mom revealed their plan to seek out the Ancient Weapons and the One Piece. Kaidou also betrayed his previous ally, the Kurozumi Family, by beheading Orochi while annexing their territory for his project. Kaidou also offered Orochi's subordinates to join his crew or die. During the Ninja-Pirate-Mink-Samurai Alliance's raid on Onigashima, both Kaidou and Big Mom were defeated by three captains from the Worst Generation—Luffy, Law, and Kid.
New Fish-Man and Flying Pirate Alliance
The New Fish-Man Pirates and the Flying Pirates, led by Hody Jones and Vander Decken IX formed an alliance in order to overthrow the Ryugu Kingdom. The two conspired to have Hody break into the palace while Decken could capture Shirahoshi and marry her. However, the plan failed, and the alliance did not last very long, with Hody even declaring Decken useless. After Decken sent Noah after Shirahoshi, Hody stabbed him with a trident in order to send Noah down towards Fish-Man Island, effectively ending their alliance.
Kid, On Air, and Hawkins Pirate Alliance
During the Punk Hazard Arc, three captains of the Worst Generation—Eustass Kid, Scratchmen Apoo and Basil Hawkins—met on the Kid Pirates' base to discuss the terms of an alliance for the sole purpose of defeating Shanks. Despite some minor altercations, the three were eventually able to come to terms, and their alliance was reported in the newspaper. After Law and Luffy's victory over Doflamingo, the three pirates were relieved that the two were not going after the same Emperor they were targeting.
Suddenly, Kaidou landed on their base and the three found themselves face-to-face with him. Apoo was already working for Kaidou and betrayed the others, and Hawkins decided to join him since it was his only chance to stay alive. Kid, on the other hand, was badly beaten and imprisoned by the Emperor. Killer became a victim of a failed SMILE fruit, and went by the alias Kamazo and became the shogun's personal assassin, until he failed his mission to kill Toko and was imprisoned by the Beasts Pirates. Because of their betrayal, Kid declared that the alliance between the three pirate crews is over.
Anti-Straw Hat Alliance
After Doflamingo's defeat, many pirates who relied on Joker's merchandise were immediately troubled at their sudden shortage of weapons. As such, they quickly created an alliance, intending on destroying the Straw Hat Pirates who defeated him. They also planned on forcing the current king of Dressrosa, King Riku Doldo III, to take responsibility for Doflamingo and force him to complete his quota for them. However, just as the alliance confronted the Straw Hats and their new fleet, they were quickly annihilated by Marine Admiral Fujitora.
Sanji Retrieval Team-Fire Tank Alliance
This alliance was formed between the Sanji Retrieval Team—a group consisting of Luffy, Nami, Sanji, Chopper, and Brook of the Straw Hat Pirates, Jinbe of the Sun Pirates, and Pedro and Carrot of the Mokomo Dukedom—and the Fire Tank Pirates, as well as Caesar Clown who was recruited by Fire Tank captain Capone Bege. The alliance's primary goal was to assassinate Big Mom during her Tea Party.
Between one and three days before the Tea Party, Bege recruited Caesar, who was being forced to work in a factory for the Big Mom Pirates. Caesar was forced to serve Bege due to Bege possessing his disembodied heart, and developed KX Launcher weapons to kill Big Mom. The Sanji Retrieval Team wished to stop the Tea Party in order to rescue Sanji's birth family, the Vinsmoke Family, from being assassinated during the event, so on Jinbe's suggestion they teamed up with the Fire Tank Pirates to best achieve this goal.
Bege had no issue with the retrieval team's objective, but ordered Luffy to aid in his plot by going out and destroying Big Mom's portrait of Mother Carmel, which would cause Big Mom to have a psychological crisis, unleash a deafening scream that would incapacitate her crew, and become weakened. Luffy agreed to this, despite his role being the most dangerous. Due to his role as the mastermind of the assassination plot, Bege held the most authority over the entire alliance. He gave Luffy and his team freedom to come up with their own plan to enter the tea party venue and rescue the Vinsmokes, but ultimately had oversight in terms of setting those plans up. The rest of the Sanji Retrieval Team focused on saving the Vinsmokes, while Caesar was tasked with flying in a mirror which the alliance would use to escape after the assassination. Going through the mirror would be facilitated by Mira Mira no Mi user Charlotte Brûlée, whom the Sanji Retrieval Team had captured earlier for their own plans.
The alliance succeeded at breaking into the wedding venue, destroying the portrait, and freeing the Vinsmokes, but Bege's plot ultimately failed when Big Mom's scream blew up the KX Launcher shots in midair and shattered their escape mirror. The Vinsmokes joined the alliance and helped them to briefly stave off attacks from the Big Mom Pirates, but ultimately the alliance was defeated and trapped. However, they were able to escape through a stroke of fortune as the Tamatebako, which had been given to Big Mom from Fish-Man Island as a gift, fell to the base of the Whole Cake Chateau and exploded, causing the Big Mom Pirates to fall to the ground below. Sanji and Caesar flew the Sanji Retrieval Team and Fire Tank Pirates to safety, where the three parties dissolved their alliance and went their separate ways.
Not long afterwards, however, Bege's wife Charlotte Chiffon decided to aid Sanji and her sister Charlotte Pudding in baking a cake for Big Mom in order to stop her from going after the Straw Hats, as she wished to repay a debt she owed to them for saving her twin sister Lola's life two years ago. Hours later, the Fire Tank Pirates reunited with Chiffon and took her team and the cake to Big Mom. On the way, Bege got into an argument with Sanji over whether or not to poison the cake; Sanji won out and the cake was not poisoned. The Fire Tank Pirates made their way to the Straw Hats as they were being pursued by Big Mom, and led Big Mom away from them with the cake as Sanji returned to his crew. The Fire Tank Pirates eventually dropped off the cake at Funwari Island, far enough away to give the Straw Hats time to escape Totto Land, before they escaped from Totto Land as well.
The Anti-World Alliance was a non-canon allied fleet of both pirates and Marines, who banded together to deal with Byrnndi World and his crew, the World Pirates. During World's later years, in his pursuit for freedom, World became overly aggressive, attacking not only the citizens and the Marines, but fellow pirates as well. As such, the World Government proposed an alliance between the Marines and the pirate crews hostile to World. In the end, World was betrayed by his own crew during the battle between the World Pirates and the alliance, who had been convinced by Cipher Pol agents to defect. After World was captured and his closest companions fled, the alliance could be assumed to have been disbanded.
Silver Pirate Alliance
- Further information: Silver Pirate Alliance
The Silver Pirate Alliance is a non-canon alliance made up of multiple pirate crews, whose main purpose seems to be capturing rival pirate crews with bounties and stealing their treasure. The Silver Pirate Alliance, unlike a normal pirate alliance where the leaders of the individual crews are considered equals, have a hierarchy more similar to a fleet, with the pirate known as Bill as their leader. The alliance has been picking up crews along the Grand Line who were doomed to fail, and promise them a new lease on life. Bill appears to be doing deals with the Gran Tesoro. They've been active in the New World since one year prior to the current timeline, and have already taken down over a hundred of rivalling pirate crews. While Bill appears to be a charismatic leader who worries for his comrades, in truth he intends to sacrifice all of them for their bounties when they run out of uses, and anyone who falls short of his standards were sent to work in the underground mines as slaves. Having no genuine care for any of them, Bill ultimately lost to Luffy, he and the headquarters sank to the depths of the sea, and the alliance broke apart.
Concludes non-canon section.
- The World Government fears that if at least two of the Four Emperors ally together, they could cause an upset in the balance of power in the world.
- Interestingly, Buggy urged his captain Gol D. Roger to accept an alliance with Shiki though his cries fell on deaf ears as his captain enjoyed his freedom too much to consider an alliance. Years later as a pirate captain himself, Buggy would strike up an alliance with Alvida, meaning that in contrast to his former captain, Buggy seems to favor alliances between crews (especially if they have a common enemy).