OZ-13MS Gundam Epyon

The OZ-13MS Gundam Epyon was a close-combat Gundam created by Treize Khushrenada whilst under confinement by the Romefeller Foundation in After Colony 195. Designed based on data from the OZ-00MS Tallgeese and the five Operation Meteor Gundams, Epyon embodied Treize’s philosophy of honourable close combat by eschewing long-range weapons in favour of a powerful beam sword and heat rod. The mobile suit featured the Epyon System, a modified version of the ZERO System, and could transform into a dragon-like mobile armor mode for high-speed flight.

Overview

Epyon represented Treize’s ideals about warfare and honour. Believing that cowardly long-range weapons removed the human element from combat, Treize designed Epyon exclusively for close-quarters battle. Its primary weapons were a directly generator-connected beam sword whose length and intensity could be adjusted, and a segmented heat rod mounted on a shield that could entangle or slice through enemy mobile suits.

The mobile suit’s defining feature was the Epyon System, Treize’s modification of the ZERO System. Whilst functionally similar to the system installed in the Wing Gundam Zero, the Epyon System had philosophical differences—where the ZERO System calculated paths to perfect victory, the Epyon System focused on the battle itself, encouraging pilots to embrace combat rather than merely win it. This distinction reflected Treize’s belief that accepting the tragedy and beauty of battle was essential to understanding war’s true nature.

Epyon’s transformation capability allowed it to reconfigure into a mobile armor mode that resembled a mythological dragon. In this form, the mobile suit achieved high-speed flight ideal for space cruising, though its primary weapons became inaccessible except for the Epyon Claws, which also served as landing gear.

Design

Concept and development

Following his relief from command of OZ and placement under house arrest by the Romefeller Foundation, Treize Khushrenada had time to contemplate the nature of warfare and the role of the Gundams in the conflict. Intrigued by the Gundam pilots and their machines, Treize decided to create his own Gundam that embodied his philosophy of honourable combat.

Using data from the Tallgeese—the prototype mobile suit he had helped test—and intelligence gathered from encounters with the five Operation Meteor Gundams, Treize designed Epyon as a “duelling” mobile suit. He deliberately equipped it with short-range weaponry only, rejecting the long-range beam rifles and missiles that dominated modern mobile suit combat. To Treize, such weapons were cowardly, allowing soldiers to kill without facing their opponents directly.

Treize also acquired or developed a modified ZERO System, which he installed in Epyon’s cockpit. Unlike the original system, the Epyon System required pilots to wear a special helmet when interfacing with it. Any technical differences from the ZERO System remained unknown, but philosophically, it seemed to emphasize the experience of battle itself rather than merely calculating victory.

Treize hoped that a Gundam pilot would come to pilot his creation, particularly Heero Yuy, whose dedication to his mission and willingness to face death impressed Treize. When Heero indeed sought out Treize intending to assassinate him, Treize presented Epyon to him instead, offering the mobile suit as both gift and challenge.

Technical features

Epyon stood 17.4 metres tall and weighed 8.5 tonnes empty, slightly larger and heavier than most Operation Meteor Gundams. Constructed from Gundanium alloy, it possessed exceptional durability and resistance to beam weapons. The mobile suit’s chest mounted a Search Eye system similar to the Shenlong Gundam’s, providing enhanced data gathering for close-range combat.

The transformation system allowed Epyon to reconfigure between mobile suit and mobile armor modes. In mobile armor mode, the mobile suit resembled a dragon with outstretched wings, achieving high-speed flight ideal for space operations and atmospheric travel. However, this mode restricted weapon access to only the Epyon Claws, making it primarily a transportation configuration rather than a combat form.

Initially, Epyon lacked head-mounted weapons, reflecting Treize’s focus on melee combat. However, after Zechs Merquise joined White Fang and Epyon became part of their forces, a pair of vulcan guns were added to the head to provide limited ranged capability.

Armament

Beam Sword

Epyon’s primary weapon was an extraordinarily powerful beam sword connected directly to the mobile suit’s generator via a power cord. Unlike beam sabres that ran on internal energy capacitors, this direct connection allowed the beam sword’s length and intensity to be adjusted according to the situation. At maximum output, it could inflict damage severe enough to destroy objects as large as the space fortress Bulge.

The beam sword’s variable output made it versatile—it could be adjusted for precision cutting or extended to massive size for devastating strikes against large targets or multiple opponents. The direct generator connection also meant it would never run out of power during extended combat, though the cord could theoretically be targeted to disable the weapon.

Epyon Claws

Mounted on both forearms, the Epyon Claws served dual purposes. In mobile armor mode, they functioned as landing gear, allowing Epyon to land and take off smoothly. In combat, they could tear through enemy armor with devastating effect, acting as close-range weapons when the beam sword was unavailable or inappropriate.

Epyon Shield

Epyon carried a small shield mounted on the left arm. Its surface was treated with anti-beam coating to provide protection against beam attacks. Despite its compact size, the shield proved remarkably effective, capable of blocking even powerful beam weapons. The shield’s bottom housed the heat rod weapon system.

Heat Rod

The heat rod was a segmented whip-like chain weapon housed in Epyon’s shield. When deployed, it could extend significant distances to entangle opponents or trip them. When heated, the rod could cut through mobile suit armor. A single swipe with this weapon could destroy up to three OZ-06MS Leo mobile suits, demonstrating its effectiveness against mass-production units. The heat rod’s flexibility made it ideal for capturing or disabling enemy mobile suits without destroying them, fitting Treize’s philosophy about understanding one’s opponents.

Vulcan Guns

Added later by White Fang after Zechs joined the organisation, the pair of head-mounted shell-firing weapons provided limited ranged capability. With a high rate of fire but little power, they were generally ineffective against mobile suits but could damage lightly armoured areas such as sensors. They were ideal for shooting down missiles, small vehicles, and other lightly armoured targets.

Sturm Und Drang (Endless Waltz variant)

In the Glory of the Losers manga and later media, Epyon received additional equipment called Sturm Und Drang (German for “Storm and Stress”). These small wing-like devices used technology similar to the OZ-13MSX2 Mercurius’ planet defensors and could be attached to Epyon’s forearms in “Defense Mode” to generate powerful defensive force fields capable of blocking the Wing Zero’s twin buster rifle. Alternatively, they could attach to the beam sword in “Zweihander Mode” to generate a massive beam blade. When using this equipment, the Epyon Shield was mounted on the rear skirt armor.

Special equipment

Epyon System

Treize installed a modified version of the ZERO System in Epyon’s cockpit, known as the Epyon System. It operated similarly to the Wing Zero’s ZERO System, predicting battle outcomes and forcing pilots to follow optimal combat paths. However, pilots wore a special helmet when using the system, and its philosophical approach seemed to differ from the original—where the ZERO System focused on achieving perfect victory, the Epyon System emphasized the battle itself.

The Epyon System’s psychological effects were similarly severe. It flooded pilots with visions of potential futures, showing them deaths, victories, and the consequences of their choices. Only pilots with exceptional mental strength could control it without succumbing to madness. Zechs Merquise later modified the system to control White Fang’s mobile dolls, demonstrating its potential for fleet-level command applications.

Search Eye

Mounted on Epyon’s chest, the Search Eye gathered data that cameras and antennas could not capture. Used primarily in close combat, it was of the same type as the Shenlong Gundam’s sensor system, providing enhanced situational awareness during melee engagements.

Mobile Armor Mode transformation

Epyon could transform into a dragon-like mobile armor mode for high-speed flight and space cruising. In this configuration, the mobile suit achieved exceptional velocity ideal for rapid repositioning and atmospheric re-entry. However, the transformation limited weapon access to only the Epyon Claws, making this primarily a transportation mode rather than a combat configuration.

Operational history

Creation and presentation to Heero Yuy

In late AC 195, following his relief from command of OZ and placement under house arrest, Treize Khushrenada designed and constructed Epyon. When Heero Yuy sought out Treize intending to assassinate him, Treize surprised the pilot by presenting Epyon as a gift instead. Treize explained his philosophy about honourable combat and warned Heero not to be a “winner” when piloting it—meaning that achieving victory should not be his focus, only the fighting itself and understanding the nature of battle.

Heero accepted Epyon, intrigued by both the mobile suit and Treize’s unusual philosophy. However, he did not kill Treize, perhaps recognizing something worthwhile in the man’s ideals despite their positions as enemies.

Heero’s struggle and the duel at Sanc Kingdom

When the Romefeller Foundation launched its invasion of the Sanc Kingdom, Heero piloted Epyon into battle against the attacking forces. However, having not yet mastered the Epyon System, Heero suffered a near-nervous breakdown from the visions the system forced upon him. Unable to distinguish between reality and the system’s predictions, he fled the battle, demonstrating the severe psychological toll the system inflicted even on soldiers as mentally resilient as Heero.

Relena Darlian’s brother, Zechs Merquise, arrived in the Wing Gundam Zero having heard of the invasion, but was too late to prevent the kingdom’s fall. Zechs and Heero duelled, piloting Wing Zero and Epyon respectively. The two mobile suits fought to a stalemate, with neither pilot able to determine victory using their respective Zero Systems. Both combatants ceased fighting, unable to resolve their conflict through the systems’ predictions alone.

In a remarkable exchange that would define the final phase of the war, Heero and Zechs traded mobile suits. Heero took the Wing Zero whilst Zechs claimed Epyon, each pilot finding something in the other’s machine that resonated with their evolving understanding of the war.

Zechs and White Fang

Shortly after claiming Epyon, Zechs joined the colonial rebel organisation White Fang, which claimed to defend the colonies against Earth’s aggression. Reverting to his birth name Milliardo Peacecraft, Zechs became White Fang’s leader and fought against the forces of the Earth Sphere Unified Nation with Epyon.

During this time, vulcan guns were added to Epyon’s head, providing limited ranged capability that the original design lacked. Zechs also modified the Epyon System to control White Fang’s mobile doll forces, using the system’s predictive capabilities for fleet-level tactical command.

Final battle and presumed destruction

In December AC 195, Zechs piloted Epyon in the final battle of the war around the massive space station Libra. He challenged Heero in the Wing Zero to a decisive duel. The two fought on and around Libra as the station began its catastrophic descent toward Earth.

The battle reached a stalemate as they arrived at the last surviving section of Libra, which was falling toward Earth. Taking the fight inside Libra itself, Heero and Zechs continued their duel until Heero severed Epyon’s left arm with Wing Zero’s beam saber, achieving a decisive victory. As Heero prepared to use Wing Zero’s self-destruct to destroy the section of Libra, Zechs convinced him to leave. Zechs used Epyon to destroy the reactor powering that section of the station, preventing it from impacting Earth.

Both Zechs and Epyon were presumed lost in the resulting explosion. However, both survived—Zechs presumably escaping before the final detonation.

Mars Century era

In Mars Century 0022, Epyon resurfaced, piloted once again by Zechs Merquise as leader of the revolting Lanigreen Republic. The mobile suit had been reconstructed with its severed left arm rebuilt and twin beam cannons added to the legs (the head portion in mobile armor mode). This upgraded version, referred to as Epyon Ares, engaged in battle with Epyon Bai (also called “Nataku”), a customised white Epyon piloted by Chang Wufei. The beam cannons were operable only in mobile armor mode, significantly improving that configuration’s combat capabilities.

Production

Design and development

The Gundam Epyon was designed by Okawara Kunio for the 1995 anime series Mobile Suit Gundam Wing. As a counterpoint to the other Gundams, particularly the Wing Zero, Epyon’s design emphasized close combat and transformation into a dragon-like form, creating a visual and thematic opposition between the angel-winged Wing Zero and the demonic Epyon.

The mobile suit’s name derives from “Epyion,” relating to Greek mythology and concepts of pain and suffering, fitting Treize’s philosophy about accepting war’s tragic nature. The design’s red and orange colour scheme contrasted sharply with most Gundams’ blue and white colouration, emphasizing its unique role and philosophy.

Katoki Hajime later redesigned Epyon for Mobile Suit Gundam Wing: Endless Waltz and subsequent media, adding the Sturm Und Drang equipment that provided additional combat options whilst maintaining the close-combat philosophy.

Reception

The Gundam Epyon became extremely popular amongst fans for its distinctive dragon-like design, powerful melee weapons, and association with both Heero Yuy and Zechs Merquise. Its philosophical approach to combat—rejecting cowardly long-range weapons in favour of honourable close combat—resonated with viewers and provided interesting contrast to the overwhelming firepower of mobile suits like the Wing Zero.

The mobile suit has been featured extensively in model kit releases, including Master Grade, Real Grade, and SD versions from Bandai, with the Sturm Und Drang variant released as a P-Bandai exclusive. Epyon became Zechs’ primary mobile suit in the Dynasty Warriors Gundam series, cementing its association with the character.

Specifications

Specification	Value
Model number	OZ-13MS
Name	Gundam Epyon
Unit type	Prototype transformable close-combat mobile suit
Manufacturer	Treize Khushrenada
Operator	Sanc Kingdom, White Fang
First deployment	AC 195
Accommodation	Pilot only, in cockpit in torso
Height	17.4 m
Weight	8.5 t (empty)
Armour	Gundanium alloy
Powerplant	Ultracompact fusion reactor
Equipment	Epyon System, Search Eye, Mobile Armor Mode transformation
Fixed armament	Beam sword (generator-connected), 2 × Epyon Claw, Epyon Shield with Heat Rod, 2 × Vulcan Gun (later addition)
Optional armament	Sturm Und Drang (Endless Waltz variant)
Pilots	Heero Yuy, Zechs Merquise

Variants

Epyon Kaiser

A variant of Epyon appearing in side stories.

Epyon Bai

Also known as “Nataku”, this customised white-coloured Epyon was developed and piloted by Chang Wufei in New Mobile Report Gundam Wing: Frozen Teardrop. It featured new weaponry adapted for Wufei’s combat style.

Epyon Ares

In Frozen Teardrop, the original Epyon was reconstructed by the Lanigreen Republic with the severed left arm rebuilt and a pair of twin beam cannons added to the legs (head portion in mobile armor mode). These beam cannons were operable only in mobile armor mode, improving that configuration’s combat capabilities significantly.