- "Dream and hope as they might, the NEXT pilots know that those who dare take on giants rarely live to tell the tale."
- — The narrator.
Arms Forts (アームズフォート) are huge war machines that appear in Armored Core: For Answer.
Arms Forts (AFs for short) were created by The League during the years following the National Dismantlement War in attempt to find a reliable military source in order to maintain control. They are the successors to the Mobile Fortress' seen in Armored Core 4. Fearing the independence and strength of the now abundant NEXTS might one day be their end, the League built Arms Forts as a means to counter them. Crewed by thousands of expendable soldiers, Arms Forts were massively scaled up weapons that the League could control, and therefore trust. Possessing firepower far and away surpassing that of a NEXT, they have become the perfect solution to the League's needs. Because of the expense of building these behemoths, not all Arms Forts are mass produced.
List of Arms Forts
A waterborne Arms Fort from Interior Union, armed with oversized laser blades and missiles, the Stigro is the fastest of all Arms Forts, but as a water-based weapon, its reach is somewhat limited. While primarily designed for obliterating enemy naval fleets, it is also slightly capable of facing NEXTs in single combat with its extreme speed that surpasses most NEXTs even in Overboost, and difficult to avoid missile salvos.
It is mentioned that the Stigro is AI controlled, which accounts for its superb accuracy but limited tactical flexibility. This may be that the G forces present from its constant Overed boost that prevent human pilots and crew from being able to function properly onboard.
- Appears in Attack on Naval Port of Mimir (but it doesn't move or shoot), Defeat AF Stigro and as an ally (or enemy on Hard) in Defeat the 8th Fleet
A huge walking hexapod Arms Fort created by the Bernard and Felix Foundation. Designed like a gargantuan fortress on a hexapod chassis, with 10 aircraft carrier decks of increasing size from bottom to top strapped to its front and rear ends, it stands approximately 600m tall and 2,4km long, and moves at a leisurely 20km/h. In true BFF fashion, the Spirit's primary armament consists of two enormous three-gun turrets mounted fore and aft of its main superstructure. These weapons, while slow to aim and useless at close range, are just-about-intercontinental arms fort killers, making any form of large-scale assault against a Spirit a most costy proposition. In addition to this impressive capacity for long-range demolition, the Spirit-class carries numerous smaller and shorter-ranged gun turrets on the undersides of its aviation decks, suitable for dealing with any large ground target too small to warrant the use of the main batteries. Contrasting this massive arsenal of low-cost munitions delivery methods, there are also numerous missile launchers of the VLS variety built into the edges of the aviation decks, some carrying cruise missiles, others loaded with much needed anti-air missiles to fight back against the type of aerial assaults that the main battery might be too slow to keep up with. As a final touch, several autocannon CIWS are mounted along the topside of the aviation decks. As a final note on its destructive power, there's an abundance of real estate on its aviation decks, perfect for housing the army that'll be used to capture and hold the ruins of whatever enemy stronghold the Spirit might point its guns at. Unfortunately, all this firepower poses a serious fire hazard, and while having some firefighting capability is a requirement for deployment, there's a limit to how much if it can be reasonably crammed into a vehicle that's not even supposed to be hit in the first place. As a result, while everything that's actually important to the function of the arms fort is covered with a few dozen battleships' worth of armour, and while the damage control teams are adequate for managing basic battle damage and ammunition restocking mishaps, these measures might be found to be inadequate should an enemy force launch a successful precision attack on the exposed weapons on the arms fort's exterior.
A partially-rebuilt wreckage of a Spirit-class arms fort, possibly the Motherwill, appears in Armored Core: Verdict Day as an optional boss. Although its large caliber cannons are missing in this iteration, its VLS cells are fully stocked with missiles, and it possesses numerous short-range plasma cannons.
- Appears in Defeat The Spirit of Motherwill
- Appears in Destroy the Spirit-class Moving Fortress
A one of the very fast Charge-class Algebra transport and support AFs with a shredder-like apparatus attached to the front, its most notable feature is its ability to carry, maintain, and deploy a swarm of aerial combat drones. Its appearance is that of an overturned soup bowl covering its suspension and tracks, with a monolithic rectangular structure laying lengthwise over its top. Although built primarily for high speed with no emphasis on offense, it carries several combined missile and autocannon turrets on top of the platform covering the top of the suspension, just below the rectangular tower superstructure. The main drawback of this AF, aside from its lackluster armament, is that uneven terrain might require that the edges of the "soup bowl" be raised so as to not dig themselves in, leaving the treads inside momentarily vulnerable. The drones, not to be forgotten are each equipped with two automatic recoilless rifles, and are launched from the towering superstructure as it unfolds after the tracks below the skirt armor have been disabled. Briefing materials indicate that multiple Cabracan-like Arms Forts exist as 'Charge Type Arms Forts'.
Mass-produced Arms Forts utilized by GA and Interior Union; GA Land Crabs are equipped with High Caliber Cannons, whereas the Interior Land Crabs are equipped with very accurate Strafing Lasers (both of these designs are also equipped with six missile launchers mounted on the sides below and between the main weapons). Using treads mounted on articulated "legs" with similarities to those of a crab, this particular AF has excellent terrain-crossing capabilities for its size, and a top speed of 50km/h on even ground. They serve both as mobile fortresses providing heavy firepower and carrier units, capable of deploying small groups of Normals. Their main weakness lies in their thinly armored underside.
- Appears in Attack on Richland, Rescue the GA Transport Unit (manned by Interior Union) and Ambush Sphere Invasion Forces (Hard Mode). 
Omer Science's Arms Forts, flight capable and equipped with a High Intensity (HI) laser cannon that rotates a full 360 degrees around the craft, as well as ventrally mounted VLS missile cells. Unlike other Arms Forts, the Eclipse has very light armor, and therefore relies on its speed and maneuverability to avoid damage. Its laser cannon is also shown to have a triple shot mode. Omer has numerous Eclipses at their disposal.
Produced by Omer and Interior, Answerer is a floating Arms Fort armed with the latest in Kojima technology, including Kojima beams, Kojima missiles, and Assault Armor (can sometimes be disabled by destroying the "spikes" hanging down from the ball-like lower core section), as well as conventional technology, such as missiles and HI lasers. Its main defense is its super Primal Armor, which renders most NEXT grade weaponry ineffective with the exception of blades and a few other weapons, and also makes it impervious to long range attack. Heavy armor is used to protect its core; however, to reduce its weight this AF only uses standard armor for its outer shell. In the hard difficulty, its very presence can wear down the Primal Armor of an NEXT due to high Kojima particle output.
- Appears in Defeat AF Answerer
A modified Land Crab developed by TORUS with several Sol Dios Cannons that are capable of operating independently from the main unit in a manner akin to Orbit weaponry. The Sol Dios Cannons take a while to start up, potentially allowing a fast moving NEXT to destroy both the carrying vehicle and the cannons before they can become active (only possible in hard mode). They are shown to also have Assault Armor as well as an amazing ability to fire in every possible direction (backwards included).
- Appears in Defeat Unidentified AF
Global Armament's greatest Arms Fort, it is best described as a several mile long giant train equipped with long range ballistics in the form of huge gatling cannons and heavy missile ordinance. Internally, it boasts a large carrying capacity for normals and possible production capabilities. It also boasts an impressive speed for an Arms Fort, rivaled only by the Land Crab and surpassed by Stigro, both if which it is noticeably many times more powerful, making it an all around amazing weapon. Unlike most Arms Forts, Great Wall cannot be damaged by NEXT grade weaponry thanks to its thick armor; the only way to effectively destroy this Arms Fort is to attack its reactor. Many consider it the "greatest land-based weapon" ever built. Despite its armor, through a glitch it is possible to destroy it from outside using a grenade launcher and knowing the location of its reactor. There are trapezoidal platforms on the side. Jump onto the fifth from the front, look 45 degrees toward the front and down a little (the reactor is at height 150 on the altimeter). The Oigami grenade launcher can destroy the reactor from the outside in 1-2 hits that way.
- Appears in Defeat AF Great Wall
ORCA's special, custom-made AF, the Jet is heavily armored on all sides, except for a single exposed exhaust vent on its upper half. It is armed with multiple energy blades and High Impact laser cannons, easily capable of destroying a NEXT. Due to its small size and relatively low production costs, this AF was mass-produced. A smaller, far-less armored version of this AF exists, as seen in the mission "Defend Arteria Cranium (Hard)" where they can be located at the back of the facility in numbers.
- Appears in Defeat ORCA's Special AF Unit; miniature versions appear in Defend Arteria Cranium(Hard Mode, but their destruction isn't required to accomplish the mission)
The Giga Base is an amphibious Arms Fort armed with a very powerful, high-caliber main cannon (which in some missions is replaced with a large turret with two smaller cannons mounted on the sides), several smaller defense turrets, and missile launchers, making it a formidable long-range weapon. Being focused on long-range combat renders it defenseless against highly mobile units that can easily take advantage of its undefended undersides. Indeed, the small dock for ships inside of it can only be fired on with missiles, which usually hit the sides before they are able to connect, if they can gain a lock on at all. This AF is also mass produced, and it makes several appearances in-game, both on land and water combat grounds. Mission briefings and various comments note that this AF is quite old, implying that it may have been the first true AF produced.
- Also appears in Defeat AF Giga Base, "Clear Former Chinese Shanghai" and as an ally in Defeat AF Cabracan (normal mode only)