ZGMF-X31S Abyss Gundam

The Abyss is a Mobile Suit in the series Gundam SEED Destiny.

Technology & Combat Characteristics
The Abyss is a transformable unit specialized in underwater combat which can transform into a streamlined mobile armor mode which also increases its speed when operate in space. 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.

Beam weapons
The suit mounts a total of six beam weapon types, of which the strongest is the chest-mounted MGX-2235 "Callidus" multi-phase beam cannon. Other weapons includes an M107 "Balaena Kai" dual beam cannon, which 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. As its name suggests, this cannon is an improved variant of the one used on the ZGMF-X10A Freedom. Mounted in the shields are two M68 dual cannons and two MA-X223E triple beam cannons. A specialized attack of the Abyss includes firing the chest mounted cannon and the two triple beam cannons at once, unleashing a heavy attack on a target.

CIWS
A total of 3 CIWS guns are mounted on the suit, which include the standard head mounted CIWS of type MMI-GAU1717 12.5mm,which is mounted in the forehead. While the 2 MMI-GAU25A 20mm is mounted in the torso beside the MGX-2235 "Callidus" multi-phase beam cannon.

Torpedo launchers
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 upwards to fire the torpedos at a target in front of the suit. In mobile armor mode the launchers are facing forword of the suit.

Beam lance
Since the Abyss was design for aquatic combat, it is only Second Stage series that isn't armed with "Vajra" beam saber. Instead, Abyss follow trend of GAT-X255 Forbidden Blue and its successor by using beam lance in melee combat.

System 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.

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 speciallized 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 Stroud. 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.

A special ZAFT variant of the Abyss is the ZGMF-X56S/&epsilon; Abyss Impulse, which is a modified version of the ZGMF-X56S Impulse with a new Leg Flyer, enabling the Impulse to emulate the function of the Abyss as an amphibious combat unit.

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.