Zero was created by Dr. Albert Wily sometime in the early twenty-first century. Wily alluded to him during Bass’s ending in Mega Man: The Power Battle, where he mentioned he was developing a robot that would blow away both Mega Man and Bass. Schematic blueprints of his body were seen during Bass’s ending in Mega Man 2: The Power Fighters. Learning from his past mistakes, including the accidental creation of Bassnium and his construction of Bass and King, Wily constructed Zero as a far more advanced robot than anything he had ever built before, with a power level far superior using Proto Man as reference for Zero’s design. He also presumably began to create the Maverick Virus around this time. Wily even dubbed Zero his “greatest masterpiece”. However, Zero contained a flaw in his cognitive program that made him violent and unwilling to obey instructions. Because of this, Wily decided to seal him in a capsule. Decades later, in the early twenty-second century, his hiding place was found by a group of Reploids prior to the first Mega Man X game. Presumably, Zero’s hiding place was within close proximity of the place where X was discovered.

Once awakened by this group, Zero destroyed them, as well as any intruders who would dare enter Wily’s lair. Labelled a Maverick (by the definition of being a threat to humans), Zero was later cornered by Maverick Hunters inside, and Zero destroyed Garma’s unit. Not wanting to get any more comrades endangered by the mysterious Maverick, then-17th Elite Unit commander Sigma himself challenged Zero in a one-on-one battle. Even though Zero eventually gained the upper hand during the battle, Sigma was able to defeat the red Maverick after the gem on Zero’s head began to glow with a ‘W’ symbol, apparently causing Zero great pain.

Sigma punched the crystal, shattering it and defeating Zero. However, while in the facility Sigma was infected by Zero’s Maverick Virus. Zero was then brought to Dr. Cain at Sigma’s request, who analyzed him. Upon awakening again, Zero became docile and had no memories of his previous actions. He was placed under Sigma’s supervision. Zero did not show any more signs of Maverick behavior and, putting his impressive strength to good use, was enlisted into the Maverick Hunters’ 17th Elite Unit.

After Sigma declared his Reploid rebellion on June 4, 21XX, Zero was made the de facto leader of the Maverick Hunters due to being the highest-ranked Hunter who hadn’t joined Sigma at the time. Additionally, Zero was approached by Mega Man X, who sought to help fight the Maverick uprising despite not being a Maverick Hunter. Zero allowed X to join him on the battlefield.

While fighting Mavericks on the Highway, Zero discovered that X was at the mercy of Vile and came to his rescue, blasting the arm off Vile’s Ride Armor. Zero threatened to finish Vile off, forcing him to flee aboard the Death Rogumer. X lamented his inability to defeat Vile, but Zero assured him that he needed time to grow and that he could one day become as powerful as himself. He then ordered X to continue fighting Sigma’s rebellion around the world, while he performed reconnaissance in order to find Sigma’s new fortress.

Once X had defeated the eight former Maverick Hunters, Zero announced that he had discovered Sigma’s hideout and that he was ready to storm it whenever X was. The two then rendezvoused at the floating fortress’ launch site, with Zero taking the brunt of the fire while X found a safer way into the base behind him. Once in the fortress, the pair encountered Vile; worried about X, Zero decided to take him on alone. However, he was overpowered by Vile’s new Ride Armor and placed in a cage. When X entered the room, Zero encouraged X to fight Vile, but the rookie Hunter was defeated. Desperate, Zero mustered the last of his power and broke out of his cage, overloading his Z-Buster on the back of the Ride Armor to destroy it – however, he gravely wounded himself in the process.

Zero laid on the ground, bisected at the waist, until X finally destroyed Vile and rushed to his side. Zero admitted that he wouldn’t survive his injuries, and encouraged X to go finish off Sigma in his stead. Additionally, if X hadn’t found the Arm Parts, he would give him his own Z-Buster in its place.

After Sigma’s defeat, the Hunters tried to salvage whatever remained of Zero from the sunken fortress and found Zero’s control chip, which had miraculously survived the destruction of his body. However, the Hunters were incapable of creating a new body for Zero because they were unable to replicate his unique body structure.

Six months later, three new Maverick leaders known as the X-Hunters contacted the Maverick Hunters, claiming to be in possession of three rebuilt fragments of Zero’s body. Although the American translation fails to reveal how the X-Hunters obtained the parts, the Japanese version elaborates that Serges made them, as they were additions that had been previously planned by Dr. Wily (including his Z-Saber). The X-Hunters challenged X to a series of duels over Zero’s parts which X wins. Dr. Cain reassembles Zero. He then appears before the battle with Sigma and destroys the Fake Zero for X.

Either way, Zero orders X to go after Sigma while he destroys the Central Computer, punching a hole in the floor to help X along. By the time X defeats the Sigma Virus, Zero causes the Central Computer to start detonating. Before disappearing, Sigma expresses confusion as to why Zero did not become his servant, mentioning that he is “the last of the Doctor’s creations.” Afterwards, X and Zero meet up on a cliff by the sea to reminisce about the game’s events.

After X escaped the digitized version of the Highway, Zero informed him that Mavericks had hacked the Maverick Hunters’ Mother Computer, stealing and corrupting data and allowing other Mavericks to run wild. While X was digitized again and sent back into the Mother Computer to shut the computer down, Zero handled the Maverick attacks in the real world. Also, later during the game, X can find four capsules known as Zero Scrambles, which allow him to “summon” Zero to perform an attack or move. However, this was only combat data of Zero and not the real one.

When the Maverick uprising in Dopple Town began, Zero and X were deployed to defend against it – however, Dr. Doppler’s forces attacked Hunter Base in their absence, forcing them to quickly return. When X was kidnapped by the traitorous Hunter Mac, Zero was forced to rescue him and kill Mac. This marked the first time Zero was a playable character, wielding his Z-Buster alongside his new Z-Saber.

After defending Hunter Base, Zero and X return to Dopple Town to fight the Maverick riots. Regardless of whether or not Zero has been damaged in-game, he will automatically appear in the first part Doppler’s Lab to assist X during the encounter with the sub-boss REX-2000. He helps X by destroying the mechanism lowering the ceiling, before departing. Later, if Zero is used to fight the optional sub-boss Mosquitus in the second stage of Doppler’s Lab (available by destroying Vile with his weakness in one of his secret stages beforehand), Zero will be damaged when the Mechaniloid crashes into him and explodes. He will then lend his Z-Saber to X while he heads back to Hunter Base for repairs, allowing him to use it in his place. If Zero is taken out of commission by Mosquitus, he will not reappear to help with the REX-2000 fight on future return visits.

After X defeats both of Sigma’s forms below Doppler’s Lab, the Sigma Virus appears and attempts to possess him. However, if Zero is still available, he will appear with Dr. Doppler’s new vaccine integrated into his Z-Saber and slash Sigma with it (if not, then a reformed Dr. Doppler will perform the act instead). This apparently neutralizes the Sigma Virus, allowing the two Hunters to leave the lab safely. Zero and X then stand atop a cliff outside the base, and X has the uncanny feeling that one day he will have to one day fight Zero for the sake of humanity.

Zero and X are deployed to Laguz Island to investigate the mysterious Erasure phenomenon, discovering that it was perpetrated by the Soul Erasers: Berkana and Gareth. The two split up to take on the island’s eight Maverick guardians before finally confronting the Soul Erasers again. They split up once more, with Zero going after Gareth while X fights Berkana. Both are successful in their respective missions, but they discover that Berkana had secretly aided in the resurrection of Sigma. Zero and X then put down Sigma together, in the process returning the souls of all the Reploids who suffered from Erasure.

The mission at Laguz Island was also the first official mission where Iris, Zero’s love interest, acted as his and X’s operator. Zero worried that her brother, Colonel from Repliforce, would be angry with him for putting her through such a difficult operation, but was happy to be working with the girl he loved.

In Zero’s story, he first encountered his mysterious creator within his dreams, who cryptically ordered him to fulfill his destiny by destroying his nemesis. When Zero awakened from the nightmare, he was immediately dispatched to the flying city Sky Lagoon, which had been attacked by Mavericks. Zero ran into Magma Dragoon during the mission, but was forced to retreat as the city fell to the Earth. He then returned to investigate the crash site, discovering that Iris had been caught up in the attack. He defended her from the giant Maverick Eregion, until Colonel suddenly appeared. Zero requested that Colonel disarm himself and his Repliforce men for questioning, suspicious of Repliforce’s involvement in the incident, but Colonel refused and instead turned his back on Zero. Shortly afterwards, Repliforce would announce their coup d’état, resulting in the Great Repliforce War breaking out.

Despite his concerns about what Colonel would think, Zero was pleased to find Iris assisting him as an operator from Hunter Base, like during the Erasure incident. Iris didn’t want Zero and Colonel to fight, torn between her care for Zero and her love for her own brother. Zero appreciated her concern, and with her help began fighting to stop Repliforce’s plans. While doing so, he also faced several non-Repliforce-affiliated Mavericks who claimed allegiance to another power, such as the traitorous Magma Dragoon.

Eventually, Colonel challenged Zero to a duel at Repliforce’s Memorial Hall; Iris begged Zero not to accept the call, but he did anyways, determined to put an end to the conflict. The two Reploids began their battle, but Iris appeared and pled with Colonel to stop, since Zero had saved her life after the Sky Lagoon’s crash. Colonel, who had always regarded Zero as a friendly rival, backed off. Frustrated, Zero stated that someone had to stop Repliforce, much to Iris’ grief.

When Repliforce’s plan was finally put into motion, Zero rushed to the Space Port to stop the ascension of Repliforce to the newly constructed space station, Final Weapon. There Zero battled Colonel, this time not holding anything back, and regrettably destroyed him in the process. After that, he traveled to the Final Weapon where he was, much to his surprise and horror, confronted by Iris. Holding Colonel’s control chip, she was now blinded by her grief for her brother and anger that Zero killed him. She then fused with Colonel’s chip, resulting in the creation of a large Ride Armor-like combat form which attacked Zero. Even though he didn’t mean to, Zero damaged the exterior power core of the structure, resulting in the destruction of the armor and Iris within. He hurried to Iris’ body, but it was too late to save her. Whispering to Zero that she wished to live with Zero in a world of only Reploids, she died in his arms. Zero, who was totally overthrown by the pain, began questioning his own reasons for fighting and the means of his own existence.

Filled with anger, he confronted General, the highest leader of Repliforce, defeating him in battle. Upon the end of the fight, General realized that someone had taken control of Final Weapon, aiming its main cannon at Earth. Zero rushed to the Final Weapon’s control center, only to find Sigma waiting for him. Amused that he didn’t remember, Sigma told Zero the story of the day they fought in Dr. Wily’s laboratory, and thanked him for giving him the Maverick Virus and allowing him to become Maverick in the first place. Zero then battled and defeated Sigma; General thanked Zero for his help and proceeded to sacrifice himself to stop the Final Weapon.

Zero escaped the destruction of the Final Weapon in a small shuttle. He pondered his own inability to protect those he cared for. He had killed his own friend Colonel, the General, and Repliforce with him, who in the end has only been manipulated by Sigma and the Mavericks. Most of all, he lost Iris, who he had cared about for so long. Questioning whether or not Reploids were destined to become Mavericks after all, he returned to Earth.

Zero also briefly appears in the ending of X’s story. X calls Zero and makes him promise to destroy him if he ever goes Maverick, but Zero finds the proposition confusing. Upon realizing how serious X is about the promise, he agrees, and X ponders their inevitable confrontation.

When Zero is chosen first by the player, he is deployed to hunt down Sigma, who suddenly reappeared in the midst of a city and caused a Maverick riot. He is able to defeat Sigma with surprising ease, revealing that it was a trap; the resulting explosion spreads a payload of the Sigma Virus across the globe. To make matters worse, the space colony Eurasia is set to impact the Earth as well, coated in yet another load of virus, thanks to Sigma’s hired mercenary Dynamo. The combination of perils threatens to irreversibly damage the entire planet.

The Maverick Hunters quickly come up with a plan to repel the Eurasia colony, using two options: the outdated Enigma cannon and a Space Shuttle outfitted with explosives (Zero would pilot the latter plan, due to being the best spacecraft pilot left in the Hunters). In order to get them in working condition, Zero and X are tasked with collecting the parts necessary – however, the spread of the Sigma Virus makes their potential business partners hostile and dangerous, leading to many battles. Additionally, the two are challenged to duels by Dynamo twice in an effort to hinder their progress. Eurasia is destroyed in time, its fragments still hit the Earth but damage is mitigated. The Colony Virus mixes with the Sigma Virus to create the Zero Virus, which in turn forms an underground void called Zero Space.

Either way, X and Zero enter Zero Space to pursue Sigma, who has hidden inside of it (if Zero has gone Maverick, then he hides there himself). Before reaching Sigma, however, X and Zero are forced to battle one another. There are several possible reasons why:

• If the player is X, he will confront Zero about how the latter’s power has been rising disturbingly quickly. He will demand that Zero go back to Hunter Base, but he refuses.

• If the player is Zero, he will be confronted by X (backed by two Lifesavers) to declare him Maverick for his bizarre immunity to the Sigma Virus. Zero is outraged, resulting in a battle.

• If Zero has already gone Maverick, then X is met with the Awakened Zero. This Zero’s mind is unclouded by judgement, and he is devoted to his destiny to destroy X.

Either way, Zero and X fight, resulting in a standstill where both lay exhausted on the ground. Sigma appears, pleased with the outcome, and Zero jumps to X’s defense to repel Sigma, who departs to patiently await their inevitable confrontation. Once the two recuperate, they team up again and put their conflict behind themselves to stop Sigma, hopefully once and for all (if Zero went Maverick, he remains unconscious while X continues to fight Sigma alone). When Zero confronts Sigma, the latter reveals that he met an “old man” who knew a lot about Zero (implied to be some form of Dr. Wily). This man helped create his newest battle body, which he uses to attack. Zero (or X) defeats him, but the explosion badly damages Zero, leaving him ruined on the ground. X defeated Sigma and Zero was normal. X lifts what is left of Zero’s body, pleading with him to not die. However, Sigma’s head still persists behind them and fires one last-ditch laser which pierces them both through the chests. Jarred awake, Zero uses his Z-Buster to fire back at Sigma as he falls to the ground, destroying the head before dying himself. In the aftermath, X would survive and take up Zero’s Z-Saber as the new ace of the Maverick Hunters.

A few weeks after the Eurasia incident, Reploid scientist Gate found a small piece of Zero’s body near the crash site. Using the information he gathered about the Sigma Virus and Zero’s DNA, Gate went mad and created the Nightmare Phenomenon, a discolored clone of Zero called the Zero Nightmare, and the near-invulnerable Reploid High Max. This resulted in a worldwide fascination with the Nightmare, and as the investigation began, its leader Isoc blamed the “ghost of Zero” for it. After being met with this news, X took the assault on Zero’s reputation personally and set out to investigate as well.

However, unbeknownst to anyone, Zero had been secretly making a miraculous recovery this entire time. Once X destroys the Zero Nightmare in one of the secret areas, the real Zero reveals himself and X is reunited with his friend, mysteriously repaired and carrying a brand new Z-Saber. Together, X and Zero set out to defeat Gate together and put a stop to the Nightmare Phenomenon. Who or what exactly repaired Zero after his apparent death in the Eurasia crisis was never directly stated. In the Weapon Center, the Dr. Light capsule hologram denied knowing who repaired him. It should be noted that the reunion between X and Zero had Zero stating that he hid himself away while he “healed”. In the English translation, Zero told X that he repaired himself.

Depending on when Zero is unlocked, he can assist X in fighting the eight Nightmare Investigators. It is also possible for him to defeat High Max, which results in a confrontation with Isoc. The scientist is elated by Zero’s power and encourages him to become even stronger, using a mysterious energy field to defend himself before fleeing the scene. Later, when storming Gate’s laboratory, Zero can also come across the body of Isoc, whose soul has left his body. Zero then hears a mysterious voice calling him the “ultimate robot” but he brushes it off and leaves to pursue the reborn Sigma.

In X’s ending, Zero is seen lamenting the unfortunate death of Gate and promising to build a utopia with the rest of the Hunters. Meanwhile, Zero’s personal ending helps reconcile the storyline between the X and Zero games. It shows Zero being sealed to remove a component from his body (presumably something having to do with the Maverick Virus or his original evil nature). This was originally going to show that the X series had ended after X6 in order to make way for the Zero series, but since the X series evidently continued past this point, this scene was retconned to take place in an unspecified time period beyond the final X series game.

Once X retires to pursue peaceful means to end Maverick conflict, Zero takes up the bulk of the Maverick Hunters’ workload. Unfortunately, the world finally being repaired after the Eurasia incident means surges in Maverick crime are more common than ever, leaving the Hunters overwhelmed. This leads to the formation of Red Alert, an illegal Maverick-hunting syndicate led by the vigilante Red.

When Axl flees from Red Alert and is pursued into the city by Mechaniloids, Zero heads out to put a stop to the chaos. He first meets Axl on the highway, helping him destroy his Mega Scorpio pursuer before arresting him and taking him into Hunter Base for questioning. After hearing Axl’s story, the Hunters are contacted by Red, who challenges them to a Maverick hunting duel over custody of Axl. At first Zero doesn’t want to get involved, and is especially befuddled when Axl insists on joining him in the field, but decides to give the young Reploid a chance to fix the mess he helped start.

As Zero and Axl fight the eight members of Red Alert, Zero gets to hear about Axl’s backstory and how Red Alert had changed for the worse recently, which is why he quit in the first place. If he speaks with Wind Crowrang, he also learns that someone affiliated with Red Alert is interested in studying his capabilities. When X finally decides to come out of retirement and help in the fight, Zero is relieved to see his old friend back in action.

Upon defeating the eight members of Red Alert, Zero and the others are sent to the Crimson Palace to face Red. When Red resigns to his fate and stays behind in a self-destructing room, Zero is forced to hold Axl back lest he rush in and die too. The trio soon learns that Sigma is indeed behind Red Alert’s Maverick actions, which Zero finds unsurprising. Sigma boasts that he will make Zero and X his servants before attacking them, but they defeat both his forms. In the aftermath, it seems as though Red has returned as he knocks down Zero and moves to give Sigma his body, but it is revealed to simply be Axl in disguise and he deals the finishing blow on Sigma. Zero is impressed by Axl’s reckless tactic paying off.

In Zero’s ending, he has a chilling nightmare of X (or a similar individual) on a murderous Maverick-hunting spree.

Some time later, it is shown that Axl has become an official Maverick Hunter who often works with Zero and X in the field. The trio are deployed to Noah’s Park to deal with the Maverick Mechaniloid Crabs-Y, and upon finishing it off they run into Vile again. Vile informs them that Mavericks have taken over the Jakob Project as he kidnaps its director, Lumine.

As the Hunters fight to suppress the Maverick uprising perpetrated by the New Generation Reploids, Zero learns that many of them admire his strength but deride him for being an outdated model who works with the Maverick Hunters. He also meets Layer, a new navigator who has a crush on him that he doesn’t openly reciprocate, keeping the relationship professional. Upon learning that Sigma is involved in the incident yet again, Zero’s memories from the Eurasia crisis return to haunt him.

After defeating the eight Mavericks, Zero and the Hunters travel to the Moon to face Sigma in his fortress. There Sigma confirms that Zero was indeed the original carrier of the Maverick Virus before challenging him to battle. The Hunters destroy Sigma, reducing him to scrap, but Lumine suddenly appears and reveals that he was using Sigma to hasten the evolution of New Generation Reploids. Zero and the others then defeat Lumine. However, Axl is struck in the head by a tentacle when he approaches Lumine’s dormant body, forcing Zero to intervene by slashing the tentacle while X destroys Lumine.

While travelling back to Earth via the Jakob elevator, Zero stands in the shadows while X carries Axl’s comatose body. Noticing that something weighed heavy on X’s mind, Zero approaches him and assures him that no matter what Lumine said about the destiny of Reploids, they would have to keep fighting no matter what.

At some point after the Mega Man X series, Zero determined that his body still contained a virus and felt uneasy about letting it linger much longer. Thus he admitted himself to a research institute, going into a coma so that his body could be studied. This study led to the creation of the Cyber-Elves, most importantly the powerful Mother Elf who was capable of eradicating the Sigma Virus. X used the Mother Elf to finally put an end to the Maverick Wars.

However, due to complications regarding the hypothetical Project Elpizo, the human scientist Dr. Weil corrupted the Mother Elf into the “Dark Elf” and began the period known as the Elf Wars. In the process, Weil stole Zero’s body and used it to create an ultra-powerful Reploid called Omega. Fortunately, Zero’s mind had been backed up by the research institute, and they were able to create a replica of his old body to place his mind in. Now in an identical new body, Zero was awoken to assist X in the Elf Wars, and together they defeated Weil and Omega. After witnessing Omega’s carnage first hand as well as with the knowledge that Omega was using his original body, he also came to the epiphany that his powers were meant for protecting his friends and what they believed in, and not for destruction. As a result, Weil was cursed with a regenerative armor and exiled, while Omega was launched into orbit.

Following the Elf Wars, Zero decided to go back into stasis, convinced that the world was in good hands under X’s protection. X protested this decision, but by the time he arrived Zero was already halfway gone, and he was able to give X a last bit of encouragement before fully slipping away into sleep.

Zero was discovered in suspended animation in an abandoned laboratory by a human scientist named Ciel, who leads a Reploid Resistance. Ciel used the Cyber-elf Passy to revive Zero, who in turn saves Ciel from the forces of Neo Arcadia that was pursuing her and her comrades. Zero, however, was suffering memory loss due to “hibernation sickness”. As it turned out, Neo Arcadia was the government of the world at this time period. Reploids were discriminated against and often deemed Maverick and terminated without justifiable cause. Copy X, a ruthless, conceited copy of the real X, was in charge of this policy. Zero agreed to join Ciel’s cause in fighting this oppression of Reploids. Zero would then go on to defeat Copy X’s Four Guardians as well as destroying Copy X himself.

After the battle with Copy X, Zero was declared missing by the Resistance, after the Neo Arcadia Core was destroyed. In truth, Zero survived the explosion, and was traveling in the desert, continuing to fight the Neo Arcadia forces that set their sights on him.

One year later, Zero is still traversing the harsh desert, and still hunted by Neo Arcadia. After another battle with the Neo Arcadian Forces, Zero finally succumbs to his injuries and exhaustion, and collapses. When he wakes up, he is now in the New Resistance Base, brought there by unknown means (later revealed to be Sage Harpuia’s doing), and meets the new members, including a new commander, Elpizo.

Ciel showed Zero her research on energy, the former thinking that it will give Neo Arcadia a reason not to fight them anymore. Zero tried to hold off Elpizo’s Operation Righteous Strike long enough for Ciel to finish her research, but in the end Elpizo still continued his plans, and Zero had to rescue him from the Four Guardians. Although Elpizo survived, he was driven to madness by the defeat, and Zero had to spend the larger half of the game trying to find him.

Zero also learned of what had happened before his sealing; the Mavericks were defeated, but some time after the Elf Wars broke out, Zero himself helped X to end them by defeating and banishing Omega, the most terrifying “Reploid” of the time. Several decades after Zero was sealed, X sacrificed his body to stop the worst Cyber-elf of all, the Dark Elf, leaving him in a more ethereal form. X’s body is destroyed and the Dark Elf is released by the now-rogue Elpizo. Zero defeats Elpizo, but the Dark Elf escapes. She and Zero appear to know each other, and X informs Zero that the Dark Elf was not always known by her current name. Her powers became a threat due to a curse by Dr. Weil, the man who started the Elf Wars, at which point people began calling her the Dark Elf.

A truce was made between Neo Arcadia and the Resistance. Ciel, having finished her energy research by creating the “Ciel System”, submitted a sample of her work to Neo Arcadia, hoping to open up the chance for peace talks. In the meantime, Zero and Ciel lead a small group through a snowy mountain, as while they were trying to locate the Dark Elf (presumably to end her curse), they found another energy signature resembling the Dark Elf located there. Upon arrival at the origin of the signal, they discover an immense ship. The Neo Arcadians had roped off the ship, so Zero decides to get a closer look by sneaking in. However, upon arrival, Ciel and the rest of the group was discovered by the Neo Arcadians. they didn’t seem to be harmed though, thus confusing Zero. Harpuia then appears and says that he’s letting them off the hook, as there’s “bigger fish to fry”. After Harpuia leaves, and Zero tries to figure out who the Dark Elf is and why she seemed familiar, Zero then hears a monstrous voice calling him. Upon arriving at the interior of the ship, Zero discovers that Fefnir and Leviathan, as well as their entire unit, was soundly defeated by an immense figure: Omega, the Devil Reploid. Zero then realizes that Omega was the one who called him, and they fight. Zero seems to defeat Omega and cause grievous damage, but then Omega started regenerating the wound. Harpuia then cuts in and is about to deliver the coup de grace when a mysterious man, Dr. Weil, tells Omega that he is to serve Harpuia as an ally. Copy X MK II then appears and announces that he revoked Dr. Weil’s exile. Weil, Copy X, Harpuia, and Omega then depart after some discussion, although not before Weil cryptically remarks that he’s interested in how well Zero will do “in that body of his.”

After a few missions, Zero and the Resistance then learn that Neo Arcadia is planning to launch a missile containing Omega into Area Z-3079, a human residential area to capture the Dark Elf. Zero infiltrates the Missile Facility and divert the missile, however, he wasn’t able to stop the launch. Not wanting to just let Neo Arcadia destroy a human population just to acquire the Dark Elf, he boards the missile to destroy Omega before it arrives at its destination. Unfortunately, Dr. Weil had anticipated Zero’s actions, so he had placed Crea and Prea on guard duty of Omega’s chamber long before the launch. While he may have defeated them, they still bought the Omega Missile enough time to reach its target. Zero barely escapes the impact of the missile, and wakes up to see Omega absorbing the Dark Elf, and transforming. Harpuia, having been retired from his position of Neo Arcadia’s military force, then attacks Omega in a last ditch effort to stop Weil and Omega, and protect humanity, even if it meant going against Copy X. Unfortunately, thanks to Omega’s absorbing the Dark Elf, Harpuia’s attacks are ineffective. Zero manages to save Harpuia and himself at the last second by telling the Resistance to transport them back.

Neo Arcadia then contacts the Resistance base, with Copy X saying they’ll call a truce under the condition that they hand over the Ciel system. However, Ciel and the Resistance declines, as she doesn’t trust them due to them destroying a human settlement just to get the Dark Elf. Their refusal results in an invasion with three units coming from the desert, the forest, and the Antarctic to attack the Resistance Base. Zero manages to take down the invasion, destroying the newly resurrected Hanumachine, Anubis Necromancess, and Blizzack Staggroff. Afterwards, Zero infiltrates the main base of Neo Arcadia to stop the invasion once and for all. Zero fights against Copy X Mark II after a debate about how things should be done. After the battle, the original X approaches Copy X and reveals that Omega and Dr. Weil had used him to gain more power, and abandoned him. Copy X then attempts to transform into his second form, despite X’s warnings about a device implanted into him, and is destroyed as a result. Dr. Weil then announces X’s death to Neo Arcadia, claiming it to be the work of the Resistance, and evokes Ordinance 8 in order to become its new ruler. Zero and X then decide to go their separate ways, although not before X cryptically informed Zero that it “was the heart that matters, not the body.”

After a few more missions and collecting data, Zero learns from Ciel that Dr. Weil is planning on re-enacting the Elf Wars. Unfortunately, Dr. Weil and Omega then takes control of all the Reploids on the planet once more. X, however, uses his powers to protect the Reploids in the Resistance Base from Weil’s control. Zero sets off to stop Weil, tracking him down to his secret laboratory, which incidentally, was close to where Zero was found at the beginning of the series.

Zero is confronted by Omega, and the two do battle. After defeating two of Omega’s forms, Zero lands with Omega’s remains in the very room which he was sealed in. Weil then reveals that Zero is a fake, and that Omega is in fact the “real” Zero, and Zero’s original body breaks out of the shell that was Omega’s previous form. Zero, however, still defeats Omega Zero after an intense duel. When Weil attempts to heal Omega of his wounds with the Dark Elf, the remaining 3 Guardians appear and attack Omega. X himself appears alongside the Guardians, and told Zero of Weil’s deception: that Omega may be using Zero’s original body, but the “fake” Zero still has his real soul.

So, regardless of Omega using his original body, Zero destroys him (presumably) once and for all, although Weil escapes. The Dark Elf, now free of her curse and called Mother Elf once more, saves Zero from Omega’s explosion and takes him back to the Resistance Base before roams free. However, X cannot roam in the real world any longer. Before X goes away, he supplies Zero with his memories of both the conclusion of the Elf Wars as well as Zero’s encapsulation, and also tells an unconscious Zero to always protect peace between Reploids and humans, a promise Zero keeps up to heart in the next game.

Eight months after the destruction of Omega, Neo Arcadia remained under Weil’s control. After Weil began to terminate humans who opposed him, several groups of humans escaped the city that used to be their utopia. When the Resistance received knowledge of this, they immediately dispatched a team to assist and protect the refugees. Zero, along with Ciel and a few other Resistance members, intercepted an assault team of Weil’s Variants (soldiers which had replaced the Pantheons) that attacked a refugee truck Caravan. After countering the attack, Zero and Ciel met Neige, a human journalist who tried everything possible to both bring all people safely to their new refuge, Area Zero – the sight of the destroyed Eurasia space colony -, and to find out the whole truth about Weil.

The Variant attack, however, was just the beginning. Zero, while investigating Area Zero, encounters Craft and the Einherjar Eight Warriors, who all serve directly under Dr. Weil. Craft tells Zero of Operation Ragnarok, a plan to destroy all inhabitable areas outside Neo Arcadia so no one can escape Dr. Weil’s rule. Zero defeats four of the Einherjar one by one, then repels an attack on Area Zero by Craft himself. The latter’s objective was to kidnap Neige, who was an old friend of his. Zero rescues Neige from the prison Craft took her to, but not before Neige managed to push a little of her ideals back into her old friend.

When the rest of the Einherjar Warriors are eliminated, Craft revolts against Weil and commandeers the “Ragnarok” space station, threatening to obliterate Neo Arcadia with the station’s laser cannon. The Resistance immediately commences the evacuation of the city while Zero storms the space station. Despite his efforts, Zero is too late and Craft opens fire, destroying the city. Zero then engages Craft in combat and defeats him. Mortally wounded, Craft asks Zero why he continues to fight for the humans that feared him and all Reploids. Zero replies that he was obligated by a promise he had made to a friend and their faith in the human race. Realizing what he’s done, Craft asks Zero to continue living up to that promise, before shutting down for good.

All is not well, however. A second laser fired from Ragnarok alerted everyone that it was still operational, and that the station is now falling down to Earth. Zero tried going through Ragnarok’s defenses, but on the way to its core he mistimed a jump across a spike pit and exploded into a bunch of circles.