The Marines are the seaborne military forces of the World Government, responsible for maritime law enforcement and naval warfare. They maintain a presence on all of the world’s known seas, through countless branch offices; however, the vast majority of their forces are focused on the Grand Line, in which resides their base of operations, Marine Headquarters. Collectively, they stand as one of the Three Great Powers, alongside the Four Emperors and the Seven Warlords of the Sea.
The duty of the Marines is to maintain a law and order throughout the world and impose the will and might of the World Government. The main purpose of the Marines is bringing any criminal to justice, with a particular focus on capturing pirates and enforcing the law. Marines constantly patrol the seas and uphold the peace.
Amongst their duties is awarding bounty hunters the bounties for the head of a criminal. They tolerate bounty hunters as a method of making their jobs easier, but are known to go out bounty hunting themselves. Apprehended criminals who are brought in alive are handed over to be made an example of. The Marines are left to ensure the transportation of these criminals to prison and/or to their execution.
The Marine Headquarters is the main division of the Marine organization that has jurisdiction over the Grand Line. It is one of the Three Great Powers in the world, alongside the Four Emperors and the Seven Warlords of the Sea, who were later replaced by the SSG’s Seraphim.
The Marines stationed there are considered “super-elites” among their comrades, and a rank at the other Marine bases is about equivalent to three ranks lower at Headquarters.
The Headquarters’ base of operations is currently at New Marineford in the New World. It was previously in Paradise’s Marineford until Sakazuki moved it after the Summit War of Marineford.
The exact process of joining the Marines is unclear. It appears that one simply needs to go to a Marine Base and ask to join, and a ranking officer, presumably the base commander, simply needs to approve the enlistment.
There are no enlistment restrictions regarding gender, and while a majority of known Marines are male, there are a number of female Marines, including Tsuru, Gion, Hototogisu, Doll, Bluegrass, Hina, Kujaku, Tashigi, Hibari, Isuka and Bell-mère. In fact, Tsuru once led a ship with an all female crew. There also seems to be no restriction based on nationality, and one can enlist even if the base they are enlisting at is outside their homeland, as seen when Koby enlisted at the base in Shells Town. Regarding race, the vast majority of Marines are human, however they are known to also employ giants and members of the Longarm Tribe.
After enlisting, in addition to receiving a unit, rank and photo ID, Marines also receive an identification code called a Marine Code. This code can be requested during contacts via Den Den Mushi with Headquarters, for boarding Marine ships during a Buster Call, or at any time to confirm their identity. Marines who join SWORD resign their Marine Code and can be cut from the Marines at any time.
