Arsenal Gear

Arsenal Gear was a submersible, mobile fortress with the ability to monitor, block, and tamper with internet communications in order to further the goals of The Patriots. Arsenal is a metaphor for the change of warfare in the last decades of the 20th Century, from a nuclear war to a war of culture, information, and espionage. Its concept was derived from the Arsenal Ship Project.

Background
After the sinking of the U.S.S. Discovery during The Tanker Incident, The Patriots sent out a dummy tanker to the exact spot where Discovery was sunk, sank it, and used it as a means to cover up the construction of Arsenal Gear, the biggest and most fearsome Metal Gear the world had yet realized. Arsenal Gear was used as a means of global censorship, control and support. Within Arsenal was housed GW, the AI designed by Emma Emmerich which controlled the entire warship, in addition to serving as Raiden's commanding officer during The Big Shell Incident. The Arsenal Gear piloted by GW was not the only Arsenal Gear in existence, however, nor was GW the only AI, as would be revealed to Raiden towards the end of his mission.

During the Big Shell Incident, Raiden and Solid Snake infiltrated the Big Shell and eventually made their way into the bowels of Arsenal Gear. After implanting a virus created by Emma Emmerich into GW, Snake and Olga Gurlukovich allowed for Raiden to be captured, gaining them access to the insides of Arsenal. After a quick torture and interrogation at the hands of Solidus Snake and Revolver Ocelot, Raiden was able to escape and enter the "stomach" of the massive warship. While inside, GW began to corrupt due to the virus, before eventually ceasing communication with Raiden completely. After Raiden did battle with the small army of production model Metal Gear RAYs guarding Arsenal, the warship was hijacked by Liquid Ocelot and sent on a crash course directly towards Manhattan, foiling Solidus' plans of handing over Arsenal to Dead Cell leader Fortune, who he knew would use the warship to challenge The Patriots' power. After launching the attack, Liquid piloted the original Marines RAYs and dove into the ocean, with Solid Snake following closely behind.

Crashing into the banks of New York City, Arsenal destroyed a sizable portion of the lower westside of the city before stopping at Federal Hall and flinging them onto the rooftop, allowing them one final battle atop the national monument. During its ascent on New York, Arsenal destroyed several United States monuments, including the Statue of Liberty, which was pushed to the front of the Immigration Museum. Presumably, the Patriots were able to use their core AI, JD, along with the other existing AIs, to cover up the truth behind Arsenal's crash into the city.

After the battle, Liquid Ocelot was somehow able to hijack the crashed Arsenal and piece the fragments of the damaged GW AI back together to use in creating his own base of operations, Outer Haven. From Outer Haven, Liquid would command the five main PMCs in the world, Praying Mantis, Werewolf, Raven Sword, Pieuvre Armament, and Otselotovaya Khvatka, under the guise of his mother PMC company, Outer Heaven.

Payload
Arsenal Gear was massive; large enough to house – and also require – a significant force for its defense. The exterior was shown when Arsenal was heading for lower Manhattan, and it was clearly just small enough to fit under the width of the Verrazano Bridge. Its on-board security defenses included:
 * 25 Production Model Metal Gear RAYs, each seperately operated by Arsenal's core AI, GW
 * An elite detachment of Arsenal Tengu, genetically modified and highly trained Gurlukovich Mercenaries armed with P90s and H.F. Blades
 * Numerous surveillance cameras for indoor security

One of its flaws, pointed out by Solidus Snake after GW was destroyed, was that it was virtually worthless without a nuclear payload, the RAYs to protect it, and full sea, land, and air support. Unless it was capable of sustaining such needs, Arsenal Gear was nothing more than "a gigantic coffin."