Neo Arcadia

Neo Arcadia (ネオ・アルカディア) is both the metropolis that much of the activities in the Mega Man Zero series takes place in as well as the government and main antagonistic force throughout the Zero series.

Foundation
Concerned about the safety of the civilians who had suffered greatly during the Elf Wars, Mega Man X founded Neo Arcadia as an organization dedicated to providing support to the refugees and survivors. Treating humans and Reploids equally and doing everything in his power to tend to them, he quickly earned a reputation as a savior among the refugees which allowed him to maintain order within the organisation and the survivors.

After the devastating conclusion of the four year long conflict, Neo Arcadia expanded from an organization into a large city with its own government. While the name "Neo Arcadia" officially referred to the government in power, the dome city itself was also called by that name. With virtually the entire world lying in ruins, unsuitable to sustain human life, Neo Arcadia became the center of the world and its only still-functioning city, housing the entire remaining world population. With the creation of Neo Arcadia as a city and government came two primary objectives: To eradicate the Mavericks who had been the cause of the wars and restoring the world from the horrible scars it had suffered after centuries of warfare. X, having earned the reputation of a legendary hero because of his efforts in the past wars and beyond, became the leader of Neo Arcadia, commonly referred to as "Master X" by citizens.

Reign of Copy X
Following X's removal from leadership at a later point in time to seal the Dark Elf using his own body, Neo Arcadia was rendered leaderless for a time. To ensure the safety and stability of the city, a young child prodigy named Ciel created a duplicate of X which took over the role of leadership. Only a few number of key people within the government were aware of this switch. Around the same time, the Four Guardians were created to fulfill Neo Arcadia's second objective of restoring the world from the marks of war, making it habitable again, while also protecting Neo Arcadia from Maverick uprisings.

Under the rule of Copy X, the Neo Arcadian society underwent some drastic changes. Instead of supporting the Original X's "philosophy of coexistence", Copy X decided that maintaining the happiness of humanity was Neo Arcadia's primary objective and that all Reploids had to ensure it stayed that way. Reploids were once more used as workforce for the humans and treated as second class citizens instead of being equal to humans. Some time afterwards, Neo Arcadia faced an energy crisis as the citizens' demand for energy continued to grow, way beyond what the city by itself could provide. Seeing the living standards of humanity threatened, Copy X decided to counteract the problem by cutting back on one of the two groups needing energy: Reploids.

To provide more energy to humans, energy supply to Reploids had to be cut short. But instead of giving Reploids less energy, it was decided to give them no energy at all. Over time, more and more Reploids were being accused of being Mavericks and found guilty in mock trials set up by the Neo Arcadian government. Copy X assembled the Eight Gentle Judges as the Inner Council of Neo Arcadia, who in turn sentenced countless innocent Reploids to death by termination.

Soon, Reploids, fearful of unjust and warrentless termination, started to actively rebel against Neo Arcadia, though with little success. Whatever rebellion arose within the bounds of the city, it was quickly and efficiently subdued.

Struck with guilt by the suffering her creation had caused amongst Reploids, Ciel began helping hunted Reploids to flee the city to establish an active Resistance outside of Neo Arcadia. Eventually, Ciel would uncover original X's partner, the legendary hero Zero, who would lend his power to the Resistance to fight Neo Arcadia, successfully completing viable missions for them and even beating the assembled Four Guardians in battle.

A heavy blow was dealt to Neo Arcadia when Zero managed to infiltrate the sanctuary of Copy X, known as Area-X, where he defeated the Four Guardians once more, resulting in the death of Hidden Phantom, and killed Copy X, rendering the city without a leader once again. News of Copy X's death were kept secret and the military made it their top priority to hunt down and kill the murderer. Sage Harpuia became the new unofficial leader of Neo Arcadia.

Interim Government
Things stayed the same under the rule of Harpuia, although he felt that fighting the Resistance was no longer necessary as long as they left Neo Arcadia alone. The new commander of the Resistance, Elpizo, however, wanted to make use of the absence of X to initiate a grand scale assault on Neo Arcadia to destroy it once and for all. This attack however was subdued by the remaining three of the Four Guardians and was followed by a retaliation attempt, which would have destroyed the Resistance had it not been for Zero and Ciel.

Making use of the manipulative powers of the Baby Elves uncovered by the Resistance, Elpizo made his way to the utmost sanctuary of Neo Arcadia, Yggdrasil, where the original X was resting, which acted as the seal for the Dark Elf. Despite Zero's efforts, the seal, as well as X's body, was destroyed, freeing the Dark Elf.

Darkness Coming
Two months following the Dark Elf's release, Ciel had finished her new energy source, the Ciel System, which she believed to finally solve the energy crisis that had humans and Reploids at each other's throats. An ancient spacecraft containing the Reploid Omega crashlanded on Earth. The Guardians attempted to destroy Omega, who was a vital part of the devastating Elf Wars a hundred years prior, but were outmatched. To make matters worse, Dr. Weil, the mad scientist who created Omega and was later banished from Neo Arcadia, had revived Copy X, who in gratitude allowed him access back into the city. Upon Weil's return to Neo Arcadia, the capture of the Dark Elf became the government's top priority. Weil manipulated Copy X like a puppet, having him remove the Guardians from their positions as military commanders and having them replaced by the Eight Judges who, by Weil's suggestion, became the new advisory board of Neo Arcadia and were immediately mobilized to search for the Dark Elf.

When the Dark Elf was located in the human residential district Area Z-3079 right at the Neo Arcadian border, Weil had a giant missile containing Omega launched directly to the Dark Elf's location in order to finally catch her, causing grave devastation within the district. Harpuia, who had stood by, watching how Weil had corrupted Copy X, decided to intervene, but he was easily outmatched by Omega. Upon the Dark Elf's capture, Copy X demanded Ciel that the Ciel System be handed over to Neo Arcadia as well as the surrender of the Resistance, but Ciel refused after seeing what Copy X and Weil had done.

Eventually, Weil set up Copy X in a battle with Zero, in which he was again killed. Making use of his position and Ordinance #8 in Neo Arcadia's constitution, Weil was unanimously proclaimed Neo Arcadia's new ruler. Combining the Dark Elf with Omega, Weil attempted to take control of every Reploid on the planet and have them do his bidding. Zero, with the help of X and the Guardians, would go on to defeat Omega, which also resulted in the Dark Elf reverting back into the Mother Elf, before flying off to a place where people like Weil would never abuse her powers for evil again.

Ragnarok Strike
Weil's true colors were revealed in the following months of his rule. A power-hungry dictator, anyone who voiced his rejection about the way he did things were immediately silenced. It did not matter whether they were humans or Reploids, anyone who refused Weil was deemed a Maverick and terminated.

People started to flee Neo Arcadia, hoping to establish themselves somewhere else where Weil's army would not find them. Most of the human settlers would try to establish themselves in Area Zero, the crash site of the space colony Eurasia, a place that had been sealed off since the disaster. Miraculously, purely organic, unenhanced nature had started to return to this place, providing the settlers with everything they needed to sustain themselves.

Enraged, Weil initiated Operation Ragnarok, a series of Neo Arcadian military operations with the objective of rendering Area Zero uninhabitable, so that there was no other place on Earth to live in other than Neo Arcadia itself. Operation Ragnarok was executed by the Einherjar Eight Warriors, Reploids loyal to Weil, commandeered by the combat Reploid Craft.

It was later revealed that Operation Ragnarok's objective was much more than just making Area Zero uninhabitable, but to completely destroy it and any other place that people might flee to. To achieve that, Weil had secretly constructed the Ragnarok satellite cannon in space. Before he could use it however, Craft, swayed by the words of Zero and Craft's old friend Neige, the leader of human settlers, fired the weapon on Neo Arcadia instead, trying to kill Weil.

Within an instant, Neo Arcadia's center was completely annihilated, turning it into a crater filled with death. At least 20 million people were reported dead. The Resistance entered the ruins of the city and rescued everyone who was still alive, evacuating them to Area Zero. Weil made one final attempt to achieve his goal by directing Ragnarok to fall on Area Zero, but Zero managed to crush his ambition.

Legacy
The survivors of Ragnarok, instead of trying to rely on the ruins of Neo Arcadia, the place that had provided them with shelter, food, water and energy for so long, took what could still be used and began living on their own. A great majority of the population moved to Neo Arcadia's periphery and many to Area Zero. Humans and Reploids joined hands to create a new, peaceful nation, the very thing that X dreamed of when he created Neo Arcadia.

Area M and Area N of Megaman ZX are stated to be old ruins connected to Ragnarok and Dr. Weil, and are locations in which old bosses from Zero 3 and 4 as well as a manifestation of Omega cn be fought. It is possible that these ruins are all that is left of the original Neo Arcadia.

Other appearances
In the Rockman Zero (manga), Neo Arcadia is ruled by Cial (Ciel's sister) and the Four Guardians, which were created by her. This version of Neo Arcadia is more strict than the games, which is visible in the first story when Fighting Fefnir hurts an old human to locate a Reploid.

In Marvel vs. Capcom 3: Fate of Two Worlds, Neo Arcadia appears in Zero's ending, the character in question misplaced in the series timeline by a wayward Silver Surfer, commenting on there being another Zero but looking different than the X series version and going by the Mega Man prefix instead.

Geography & Locations
Neo Arcadia was a city of gargantuan scale, although exact specifications were never stated. The city was home to the survivors of the Maverick and the Elf Wars, housing at least 20 million people within its center alone. The city itself was protected by an even larger domed sphere, called "Eden Dome". Not only did the dome protect the city from the hazardous conditions of the devastated post Elf Wars world, but also from Maverick Reploids roaming the outskirts. Furthermore, the Eden Dome contained its own weather control system, providing pleasant temperatures and weather conditions for the citizens of Neo Arcadia.

Neo Arcadia's power supply was provided by a huge energy facility below the city, called Sub Arcadia. Similar to the rest of the world during the Maverick Wars, nature in Neo Arcadia was techno-organic. The extend of how much of Neo Arcadia was covered with such techno-organic nature was not specified. Sites located inside the dome showed little, if any techno-organic nature. In all four wind directions around Neo Arcadia however, large forest areas can be found, rich of half artificial, half organic trees. These forest areas, namely Anatre, Dysis, and Notus, also contained ruins that were being monitored by Neo Arcadia and were off-limits to regular Neo Arcadian citizens and even most of the military personnel. Officially, these ruins belonged to an ancient, pre-Neo Arcadian civilization, while in truth, the ruins housed relics of the Elf Wars, namely, resting places of the Baby Elves as well as the key to the Dark Elf's seal.

Area X (エリアX)
Also known as the Neo Arcadia Core and Neo Arcadia Headquarters (ネオ・アルカディアの本部), is a control room from the first game located on a stationary satellite at an altitude of 3600 km. The area governs all of Neo Arcadia's unmanned space stations.

Area X-2
The central command center of Neo Arcadia in Zero 3, ruled by Copy X and Weil. From Area X-2, they command the entire Neo Arcadian army.

Neo Arcadia Shrine (ネオ・アルカディアの神殿)
Also known as the Holy Region (聖域), this is the path that leads to the Neo Arcadia Tower at the center of Neo Arcadia. It is surrounded by a completely artificial, sterile environment, and is heavily guarded by a building designed like an ancient shrine that houses an elite force of Mutos Reploids. Zero faces two Pantheon Aces, Asura Basura, and Herculious Anchus en route to the tower.

Neo Arcadia Tower (ネオ・アルカディアの塔)
Located between the Neo Arcadia Shrine and Area X. Zero fights the Rainbow Devil at the top of the tower. The tower used to be an orbital elevator for transportation between the Earth's surface and the moon, which was destroyed in the Maverick Wars. It was repaired and is now used to foil would-be infiltrators.

Train of Neo Arcadia (ネオ・アルカディアのれっしゃ)
Mode of transport for shipping goods in Zero 2. Elpizo asks Zero to seize the train's supplies for the Resistance, and he fights Panter Flauclaws between two trains.

Under Arcadia (アンダー・アルカディア)
The underground power plant of Neo Arcadia, it acts as a central core for all of Neo Arcadia's machinery. Omega was sending Dark Elf's powers out to the world from this location. During the fight between Zero and Omega, they fell deep underground into the Underground Laboratory.

Teleporter Base
Designed to transport Neo Arcadian troops to various locations on the planet. However, by the time Zero visited the location, it was running on emergency power due to Neo Arcadia's earlier destruction from Ragnarok's particle beam by Craft. Zero visited the location in order to access Ragnarok's core area, as they needed to access that area to shut down the core before Ragnarok crashes into Area Zero.

Yggdrasil (ユグドラシル)
The sanctum where the original X sealed the Dark Elf. Zero fights Elpizo in this locale at the end of Zero 2.

It seems to be located at the very core of Neo Arcadia. It houses 6 transport ports to other places (most likely to other sections of the building), where Zero fights 7 different bosses. X´s original body rests at the very top, using a huge power generator to contain the Dark Elf. It is named after the world tree in Norse Mythology.

Military
The Neo Arcadian armed forces consist of four military branches. Well-trained and well-organized for deployment on any possible battlefield, and possessing extremely high maneuverability, each of the military branches is commanded by one of Neo Arcadia's Four Guardians. Neo Arcadia's armed forces can be considered among the most powerful and well-structured organizations in the entire Mega Man franchise, a juggernaut of strength to protect the humans and reploids of Neo Arcadia. Below is a list of the four military branches in greater detail:
 * Strong Air Battalion/Rekku Gundan: the air force, consisting primarily of many fast-moving aircrafts, giant airships, and a great number and variety of flying Mechaniloids. The Rekku Gundan can dominate any region with its unrivaled supremacy in the skies, and can perform wide barrage and preemptive strikes at any location. Led by Sage Harpuia.
 * Scorched Earth Squadron/Jin'en Gundan‎: the ground troops, and the most powerful of the four armies in terms of raw firepower and armor. Consisting of units built with superhuman strength, heavily armored fighting machines, and fearsome grinder tanks, the Jin'en Gundan can level anything in its path and ruthlessly crush any opponent in battle. Led by Fighting Fefnir.
 * Deep Sea Squadron/Meikai Gundan‎: the naval and subterranean underwater forces. Consists of many major battleships and submarines and armed with a formidable arsenal of both surface and underwater firepower, the Meikai Gundan can manipulate the tides of the water itself, engulfing everything in battles above or underwater. Led by Fairy Leviathan.
 * Cutting Shadow Squadron/Zan'ei Gundan‎: the special forces. This is the smallest and least known of all the four squads, due to both its undercover methods of operation and the extreme requirements that one must pass in order to join. The Zan'ei Gundan fields some of Neo Arcadia's most intelligent and highly customized combat units. With stealth movements and attacks from the shadows, they can infiltrate any enemy base and steal information from anywhere. Led by Hidden Phantom.

Trivia

 * In Archie Comics' Mega Man series, the city where the Dawn of X storyline is set in is referred to as "Arcadia City".
 * Neo is a Greek prefix for the word "new" while Arcadia refers to a utopian vision of harmony with nature.