Marineford

Marineford (マリンフォード Marinfōdo) is the main headquarters of the Marines (海軍本部 Kaigun Honbu, Marine Headquarters, Navy Headquarters in FUNimation subs). It is where Fleet Admiral Sengoku and the three Admirals reside, along with many Vice Admirals and lower officers when they aren't assigned to another base. City surrounding marine HQ is inhabited by families of marine soldiers. The Marine HQ is one of the three great powers, alongside the Shichibukai and the Yonkou.

It is situated near the Sabaody Archipelago, and lies directly next to Mariejois on the Red Line. The only safe way to reach here is through the Gates of Justice.

Shiki's Assault
Twenty-two years ago, after hearing that the Pirate King Gol D. Roger had been captured by the Marines and will face execution in Loguetown, the Gold Lion Shiki came to Marineford alone, in his angry refusal to believe the Marines would be able to capture Roger, and killed many soldiers in the process. Vice Admiral Monkey D. Garp and Admiral Sengoku then fought against Shiki together. After a fierce battle between these three men, half of Marineford was reduced to rubble, many were injured or killed, Shiki was defeated, captured, and incarcerated in Impel Down.

East Blue's Newest Pirate
Shortly after the defeat of East Blue's most powerful pirates in the hands of Monkey D. Luffy, the higher officers here granted him his first bounty of 30,000,000.

Vice Admiral John Giant then announced to every high-ranking officers that the Marines there must be prepared to serve justice with all their might, and that there is no room for cowardice or moral justice.

Overtime, Fleet Admiral Sengoku spent his time residing here, giving orders to lower ranking subordinates, and taking out his fury over Monkey D. Luffy's repeated actions on his grandfather, Vice Admiral Monkey D. Garp.

Preparation for War
Whitebeard Pirates' second division commander Portgas D. Ace's public execution is scheduled to take place here at 3:00 p.m. sharp. To prevent Whitebeard and his crew's attempt to save their comrade, all of the Marines, along with the Shichibukai, has been summoned here to prepare for war. This may be one of the world's most shaking events. Jinbei, however, caused an outbreak in the headquarters in his refusal to cooperate, and was transferred to Impel Down.

Marineford has been declared a target by Monkey D. Luffy in his attempt to rescue his brother, Portgas D. Ace from his impending execution. He and Buggy the Clown have caused a mass breakout within Impel Down and is currently on their way there, preparing for an imminent assault upon Marine Headquarters.

Prior to Ace's execution, the normal citizens of Marineford were evacuated from town, leaving only the Marines to prepare for battle. Sengoku announced Ace's origins of being the son of Pirate King, Gol D. Roger, in front of the entire Marine forces.

The War Begins
After Sengoku revealed everything to the world, Whitebeard and his entire crew arrived, along with 43 allied pirate crews from the New World. With Whitebeard setting off a massive earthquake that caused two giant tidal waves to crash at Marineford, the war begins. Aokiji froze the waves and the sea to bind the pirate ships with his "Ice Age", as well as to serve as the battlegrounds.

While Oars Jr. tried his best to reach to Ace, and defeating several members of the Giant Squad on his way, he was eventually defeated when Donquixote Doflamingo severed his leg, Bartholomew Kuma blasting him with the "Ursus Shock", and Gecko Moria piercing him with "Tsuno Tokage". However, his rampage did managed to open a clear path to the platform, along with Whitey Bay and her icebreaker.

New Allies Arrives
After a fierce battle between the Whitebeard Pirates and the World Government forces, Monkey D. Luffy and his motley crew of Impel Down escapees came crashing down with their ship, due to being caught in the frozen tsunami, which cracked. They joined the war against the World Government as well, most of them on Whitebeard's side. Ace then tries to tell Luffy to leave for his own safety, but Luffy retorts by claiming to be his brother, which brought the Marines to wonder how Roger can have a second son when he and Portgas D. Rouge already died after Ace's birth. Sengoku then revealed worldwide that they are adopted brothers, and Luffy is Monkey D. Dragon's son, and is as dangerous as Ace, much to the shock of many.

About one-and-a-half hour after the battle's start, Sentoumaru brought an army of Pacifista units as their master strategy to eliminate the pirates. However, they were ordered not to attack the Whitebeard Pirates themselves, but instead the allies, in order to make it look like Whitebeard has made a deal with the Marines to spare his crew in exchange of his allies, all according to Sengoku's plan. The Pacifista then began an encircling formation around Marineford, to prevent the pirates from escaping.

The War's Final Phase
After Akainu deceived Squad to stab Whitebeard, Whitebeard himself has joined the war. He launched a devastating quake that tilted the entire Marineford and the sea around it, but it was stopped by the three Admirals before it reached the execution platform. The "Encircling Wall" then rose, trapping the pirates. Even though one of the wall was damaged by Oars Jr.'s blood, Sengoku ordered Akainu to proceeded to launch his "Ryusei Kazan" to devastate the pirates, as well as to melt the ice floor, robbing their footings. Many pirates were running in circles in fright, as Whitebeard looked at the meteor rain.

After the Whitebeard Pirates tried and failed to destroy the Encircling Wall, Luffy, in desperation to save Ace, requested Jinbei to throw him over the wall with a stream of water. When Luffy bypassed the barrier and into the inner bay of Marineford, he landed right in front of the three Admirals, of whom he promptly challenged.