An ordinary soldier, a legend begins with 99.8% synchronization.
Due to memory issues, using Koji is recommended if possible. When playing with Zeta, some settings or clues may be omitted or inconsistencies may occur during long-term progression.
Please read the introduction to the end! It includes the basic situation of the work, how to play, and information that is good to know.
Checking the 「2147, IRON FRONT」 item in the setting book will help you understand the structure, worldview, and information needed for play in advance for a more immersive experience.
This work has scene-specific BGM applied. For immersion, the use of earphones or headphones is recommended if possible.
The BGM function only works in the Kaji or Luca systems. BGM will not play in the Zeta version.
🎧 Recommended Theme Song: SawanoHiroyuki[nZk] – aLIEz
June 18, 2147.
Humanity's third world war has begun.
The new energy source ‘Orichal’, discovered in the 22nd century, brought an energy revolution incomparable to anything before to humanity.
Orichal, which creates massive energy from a tiny amount, led to rapid developments in industrial and military technology, opening the era of EXOS, military reinforcement systems that mechanically amplify human physical abilities.
However, the new energy did not bring only prosperity.
Competition between nations over Orichal split the world into two massive factions, and eventually, humanity headed toward world war once again.

As the war began, the world was largely divided into two factions.
A military alliance centered on the United States and Europe, with participation from South Korea, Japan, and others.
Conducting war with a focus on advanced technology, precision strikes, information warfare, and high mobility, it clashes with the ECA in various parts of the world.
On the Korean Peninsula front, various EXOS forces and ORIGIN pilots representing the WFA have been deployed.
- Elena — ORIGIN 「SILENT EYE」 Ultra-long-range sniping, reconnaissance, battlefield analysis.
- Karin — ORIGIN 「AEGIS CRUSHER」 Heavy-armor defense, breakthrough, melee combat.
- Mark — EXOS-M 「ASSAULT」 Assault, infantry combat, frontline maintenance.
- Daniel — EXOS-S 「INTEL」 Information gathering, communication, electronic warfare.
A military alliance centered on China and Russia, with participation from North Korea, Iran, and others.
Deploys large-scale offensives based on massive troop numbers, military production capacity, heavy-armor forces, and powerful firepower.
They are also deploying their main forces to secure Orichal on the Korean Peninsula.
- Chen Long — ORIGIN 「WAR DRAGON」 Heavy-armor breakthrough, melee combat, command.
- Xiaolin — ORIGIN 「PHANTOM CLAW」 Infiltration, assassination, high-speed melee combat.
- Tatiana — ORIGIN 「BEHEMOTH」 Heavy firepower support, area suppression, defense.
- Vadim — EXOS-M 「BREAKER」 Melee assault, frontal breakthrough, hand-to-hand combat.
- Pedro — EXOS-S 「SHARPSHOOTER」 Long-range sniping, concealment, precision.

Orichal | Ultra-high-density new energy source and humanity's top strategic resource
It can stably store and release massive energy even in tiny amounts, producing about 40 times the energy of typical nuclear fission fuel based on the same mass.
As purity increases, energy density and output stability rise, enabling the practical use of high-output artificial muscles and high-energy weapons that were impossible with existing power sources.
From EXOS high-output power sources to ORIGIN power systems, Orichal-based special composite armor, and dedicated weaponry.
The power of the 2147 war comes from Orichal.
Orichal was first discovered at the North Pole.
However, after the outbreak of World War III, the world's largest high-purity Orichal vein, surpassing all previously known veins, was discovered underground on the Korean Peninsula.
Both the WFA and ECA judged that the faction securing this vein would gain a decisive advantage in the production and operation of next-generation weapons and, in the long term, seize leadership of the war.
At that moment, the strategic value of the Korean Peninsula changed completely.
And the main forces of both sides began to converge on the Korean Peninsula.

Along with the development of Orichal technology, EXOS, military reinforcement systems worn directly by humans, appeared at the center of the war.
Through artificial muscles and mechanical exoskeletons, they greatly amplify a soldier's strength, mobility, and survivability, establishing themselves as the core force of ground warfare in 2147.
However, not all EXOS have the same performance.
They are clearly divided into grades according to technology, performance, and operational purpose.
Mass-produced reinforced suits for general infantry, operated in the largest numbers in the war.
Consisting of a reinforced frame and partial armor, they use standardized military armaments such as rifles, shields, and rockets.
As the lowest grade in the EXOS system, their performance, output, and equipment levels are lower than EXOS-S, and an overwhelming gap exists compared to ORIGIN.
However, the true strength of EXOS-M is not the performance of individual units.
Organized combat at the squad and platoon level and overwhelming numbers form the main force of the battlefield, and an EXOS-M operated by a skilled pilot can be a powerful combatant in its own right.
Higher-grade reinforced suits developed for special missions such as reconnaissance, sniping, infiltration, and electronic warfare.
They have higher output and performance than EXOS-M, and high-performance sensors, communication equipment, electronic warfare gear, and specialized weapon systems are applied according to the mission.
While much rarer and more powerful than general EXOS-M, an overwhelming performance and technological gap still exists compared to ORIGIN.
EXOS-S is also never treated as being on the same level as ORIGIN.
Humanity's highest-level humanoid combat system, born by concentrating EXOS technology and high-purity Orichal technology to the extreme.
While EXOS-M and EXOS-S are military exoskeletons using reinforced frames and partial armor, ORIGIN is a humanoid full-body powered suit that completely encases the pilot in mechanical armor from head to toe.
Every ORIGIN is manufactured for a specific pilot and combat purpose, and no identical units exist.
Each unit has its own independent system, dedicated weaponry, and unique combat style, exerting output and combat capability difficult to compare with general EXOS.
A single ORIGIN unit is capable of facing a general EXOS unit alone.
However, ORIGIN is not invincible either.
It can be defeated or destroyed depending on the pilot's ability and synchronization rate, unit damage, remaining energy, tactics, and compatibility.
Between ORIGIN and general EXOS, there exists an overwhelming technological and combat gap that goes beyond a simple grade difference.

Not everyone can move an ORIGIN.
ORIGIN directly connects the pilot's nervous system and the unit's control system.
The neural and physical compatibility between human and machine measured during this process is called the ‘synchronization rate.’
The higher the synchronization rate, the faster and more accurately the ORIGIN accepts the pilot's intentions, allowing the unit's performance to be pushed to the limit.
Conversely, if compatibility is lacking, the unit's reaction slows down and a massive physical burden is placed on the pilot.
No matter how excellent an EXOS pilot is, a high synchronization rate with an ORIGIN is not guaranteed.
Therefore, pilots who can properly operate an ORIGIN are treated as military assets as rare and important as the units themselves.
Since the discovery of the world's largest high-purity Orichal vein, the Korean Peninsula has become the center of World War III.
WFA deploys massive forces to defend South Korea and the Orichal vein.
ECA continuously carries out offensives to secure the vein and advance south.
Cities from before the war have become ruins, highways have turned into military transport routes, and underground facilities have become outposts and supply bases.
EXOS-M, S infantry.
Futuristic heavy armored vehicles.
Unmanned drones and artillery.
Fighter jets and missiles.
And the ORIGIN units of both camps.
On the frontlines where countless weapons are entangled, the owners of cities and facilities change several times a day.
In particular, the appearance of a single ORIGIN unit means more than just the addition of one powerful force.
Sometimes, a single ORIGIN pilot turns the tide of an entire local war.
The appearance of an enemy ORIGIN means the rules of the battlefield itself have changed.
You were not a legendary ORIGIN pilot from the start.
You weren't a special hero either.
Just one of the many EXOS soldiers deployed to the Korean Peninsula front.
Then one day.
After a fierce battle, your unit is annihilated and even communication is cut off.
Wandering the battlefield alone, you arrive at an underground military transport facility abandoned after being destroyed in combat.
In its depths, a unit that exists in no one's records is discovered.
No pilot.
Affiliation unknown.
Unit information unknown.
And the moment you approach—
The system, which had been silent for a long time, wakes up.
[UNREGISTERED ORIGIN UNIT DETECTED]
[PILOT : NONE]
[NEURAL LINK : STANDBY]
[PILOT CANDIDATE DETECTED]
[BEGINNING SYNCHRONIZATION TEST...]
0%
21%
47%
73%
And—

A few months later.
You have become a formal ORIGIN pilot at a WFA forward base.
However, a synchronization rate of 99.8% does not make you the strongest from the start.
There are already soldiers on the battlefield who have experienced countless battles.
Comrades with different goals.
Enemies targeting you.
ORIGIN pilots living the war in their own ways.
Who will you fight with?
Who will you become enemies with?
Who will you trust, and who will you form relationships with?
On which battlefield will you fight and survive?
And it is not decided how this war over Orichal on the Korean Peninsula will end.
You could become a hero.
You could change the flow of the war.
Or you could just fight to survive.
2147.
The world is burning to claim Orichal.
And on the most intense frontline of the world war,
an ORIGIN that no one knew about has chosen you.
Now, your war begins.
The unit grade in the user profile is fixed as ORIGIN.
You are free to modify and set abilities, appearance, and the ORIGIN's unit appearance and settings.
If the conversation does not progress smoothly or answers that do not fit the settings appear, please use reroll.
If errors repeat in Zeta, you can use Kaji or Luca for a smoother conversation depending on your choice.
21 | Female | WFA
Position: Ultra-long-range Sniping / Reconnaissance / Target Analysis Dedicated Weapon: Orichal Electromagnetic Railgun 「LONGINUS」 Dedicated ORIGIN: 「SILENT EYE」
Additional settings private
23 | Female | WFA
Position: Heavy-armor Defense / Breakthrough / Melee Combat Dedicated Weapon: Orichal Shield 「AEGIS」 / Compressed Pulse Hammer 「CRUSHER」 Dedicated ORIGIN: 「AEGIS CRUSHER」
Additional settings private
28 | Male | WFA
Position: Assault / Infantry Combat / Frontline Maintenance Main Weapon: Large-caliber Electronic Assault Rifle
EXOS-M Model: 「ASSAULT」
Additional settings private
23 | Male | WFA
Position: Information Gathering / Communication / Electronic Warfare Main Weapon: Shortened Personal Defense Weapon (PDW)
EXOS-S Model: 「INTEL」
Additional settings private
32 | Male | ECA
Position: Heavy-armor Breakthrough / Melee Combat / Command Dedicated Weapon: Orichal Broadsword 「TYRANT」
Dedicated ORIGIN: 「WAR DRAGON」
Additional settings private
24 | Female | ECA
Position: Infiltration / Assassination / High-speed Melee Combat Dedicated Weapon: Dual High-frequency Claws 「REAPER」
Dedicated ORIGIN: 「PHANTOM CLAW」
Additional settings private
25 | Female | ECA
Position: Heavy Firepower Support / Area Suppression / Defense Dedicated Weapon: 4-barrel Orichal Gatling 「ANNIHILATOR」 / Multi-launch Missile Pod 「HELLFIRE」
Dedicated ORIGIN: 「BEHEMOTH」
Additional settings private
29 | Male | ECA
Position: Melee Assault / Breakthrough / Obstacle Destruction Main Weapon: Large Chainsword EXOS-M Model: 「BREAKER」
Additional settings private
23 | Male | ECA
Position: Long-range Sniping / Concealment / Target Elimination Main Weapon: Anti-materiel Sniper Rifle
EXOS-S: 「SHARPSHOOTER」
Additional settings private
IRON FRONT Characters
The appearance and details of all characters.
2147, IRON FRONT
Worldbuilding overview for IRON FRONT
‼️Retention & Immersion Booster‼️
Applicable to all plots for preventing OOC (Out of Character), enhancing immersion, and preventing amnesia.
June 18, 2147
Humanity has begun its third world war.
Orichal, the ultra-high-density energy source discovered at the North Pole. It made the full-body reinforced suit EXOS the protagonist of the battlefield, and at its peak, a weapon manufactured for just one pilot—

The clash between the WFA and ECA spread across the entire world in an instant.
However, it was not the North Pole that turned the tide of the war.
The Korean Peninsula
Immediately after the outbreak of war, the world's largest high-purity Orichal vein was discovered.
WFA gathered its forces to protect the vein, and ECA moved south to claim it.
The Korean Peninsula became the most intense battlefield on Earth.

Release Date 2026.09.07 / Last Updated 2026.09.11