ZGMF-X31S Abyss Gundam

The ZGMF-X31S Abyss Gundam is a prototype transformable amphibious mobile weapon, it is first featured in the anime series Mobile Suit Gundam SEED Destiny. The unit was originally piloted by Mare Strode but after it was stolen, it was given to Auel Neider.

Technology & Combat Characteristics
The Abyss is a transformable mobile suit specializing in underwater combat and transforms into a streamlined mobile armor mode which increases its speed when operating in water. The suit is heavily armed and features a large number of beam weapons. Besides the beam weapons, the suit also features several CIWS guns, torpedo launchers, and a beam lance for close combat. When operating on ground or in space, the Abyss's variety of beam weapons allows it to function as a long range support unit.

Armaments

 * M107 "Balaena Kai" Dual Beam Cannon
 * An improved version of the Freedom's M100 "Balaena" Plasma beam cannons, the "Balaena Kai" dual beam cannon is only used in mobile armor mode, during which it usually faces forward but can swing up. Although ineffective in aquatic battle, Balaena Kai allow Abyss to fire on aerial targets as it leap from the water. The weapon is mounted on a backpack and usually points downwards when in MS mode.


 * M68 Dual Cannon
 * Another long range weapon of Abyss Impulse are two M68 Dual Cannon, capable of fire underwater. It can destroys a standard Mobile Suit with one shot


 * MA-X223E Triple Beam Cannon
 * Abyss is equipped with two sets of MA-X223E and they are located in the shields.


 * MGX-2235 "Callidus" Multi-phase Beam Cannon
 * A chest-mounted heavy beam weapon.


 * MMI-GAU1717 12.5mm CIWS
 * CIWS gun mounted between the v-fin. Used for engaging light targets, missile interception and surpressive fire.


 * MMI-GAU25A 20mm CIWS
 * Abyss also mounts two MMI-GAU25A 20mm CIWS guns in its chest to shoot down incoming missiles or enemy units at close range.


 * MMI-TT101 Mk9 High-speed Guided Torpedo
 * For underwater and land combat, the suit mounts four MMI-TT101 Mk9 high-speed guided torpedo launchers on the shields. In mobile suit mode, the shields can swing backwards to fire the torpedos at a target in front of the suit. In mobile armor mode the launchers are on the front of the suit.


 * MX-RQB516 Beam Lance
 * Since the Abyss was design for aquatic combat, it is the only Second Stage series MS that isn't armed with beam sabers. Instead, Abyss follow the trend of GAT-X255 Forbidden Blue and its successor by using a lance in melee combat. The lance can generate a small beam blade at the end.

Special Equipment & Features

 * Deuterion Beam Energy Transfer System
 * The suit is also among the new units to be equipped with the new Deuterion Beam Energy Transfer System, which allows a properly equipped battleship to remotely recharge a mobile suit's battery.


 * Operating System
 * The Abyss uses the Generation Unrestricted Network Drive Assault Module operating system.


 * Variable Phase Shift armor
 * Like the other Second Stage Series suits the Abyss has VPS armor, this technology is more energy efficient and capable of altering its strength, as well as color in the field, although this must be programmed beforehand.

History
In late CE 73, ZAFT created a new series of advanced mobile suits to succeed their previous generation of Gundams, which were all lost in the previous war. Since the Treaty of Junius banned the military use of the Neutron Jammer Canceller, these new Gundams use conventional battery power instead. One of these suits is the Abyss; which, like the ZGMF-X24S Chaos and the ZGMF-X88S Gaia can transform into a mobile armor mode which is specialized for a certain terrain. In the Abyss's case this terrain is water, where the suit outperforms all previous underwater models. Unlike previous amphibious mobile suit, Abyss Gundam can function in space.

The Abyss is initially tested at Armory One by Mare Strode. However, before ZAFT can bring it into active service, Auel Neider of the Earth Alliance's 81st Independent Mobile Battalion (also known as Phantom Pain) steals the mobile suit and escapes with it to the battleship Girty Lue, where it is given the new model number RGX-02. The Abyss is later transferred to Earth and operates from the carrier John Paul Jones. The Abyss sinks the ZAFT submarine Nyiragongo in the Indian Ocean, but is later destroyed by the ZGMF-X56S/γ Blast Impulse in a naval battle off the coast of Crete, killing Auel in the process.

Although not implemented, Courtney Heironimus in Mobile Suit Gundam SEED Destiny Astray indicates that there is a plan to fit Abyss with a Core Splendor system similar to those on ZGMF-X56S Impulse Gundam. This means that Abyss is developed to collect data for new Silhouette Pack that would allow Impulse to have better performance in underwater combat. Jess then imagines about how ZGMF-X56S/ε Abyss Impulse might look like.

Notes & Trivia

 * Abyss's head crest displays the text "X-31S ONE", which means "One" in Italian and is a reference to the Abyss's series number.
 * In its seriel number, "ZGMF" represents "Zero Gravity Maneuver Fighter", "X" means it is a prototype unit, "3" means it is designed for underwater combat, "1" is its series number, and "S" means "Second Stage".