Zero

Zero (ゼロ) is one of the three main characters of the Mega Man X series, as well as the protagonist of the Mega Man Zero series and makes an appearance as Biometal Model Z in the Mega Man ZX series. In the X series, he is one of the highest ranking Maverick Hunters who is fighting to stop the endless war between humans and Mavericks. He's a diehard warrior who doesn't hesitate to take action. However, behind his cold and emotionless attitude lies a wounded soul.

Personality
As stated, Zero acts cold and emotionless towards others, even to his partners X and Axl. However, it shown that has the capacity to care for others and to some extent, in Iris' and (in the eyes of many) Ciel's case, love. His penultimate words in Mega Man Zero 4, summarize his personality by that point: "I never cared about justice and I don't recall ever calling myself a hero...I have always only fought for the people I believe in. I won't hesitate...If an enemy appears in front of me, I will destroy it!"

In spite of not viewing himself as a hero, Zero has often displayed a tendency to sacrifice himself for the sake of others. As stated in his previous words, however, he doesn't have any major problems with fighting, unlike his pacifistic friend, X; whether his enemy is a Maverick or a human (during Mega Man Zero 3, Zero commented that Dr. Weil was no different from a Maverick to him), he will fight at his best. Another notable trait is that, despite his power, Zero has shown to be somewhat humble: he has, at times, actually viewed X as the superior Maverick Hunter, and actually considers him a hero, which seems impressive since Zero doesn't consider himself a hero.

Origin
Zero was created by the late Dr. Albert Wily sometime in the early-21st century. His first historical appearance was in the form of schematic blueprints during Bass's ending of Mega Man 2: The Power Fighters and described by Wily as his "greatest masterpiece." Learning from his past mistakes, including the accidental creation of Bassnium, and his construction of Bass and King, Wily constructed a new robot, far more advanced than anything he had ever built before with a power level far superior to that of Bass or Mega Man. Wily took the time to complete Zero, but for reasons unknown, Zero was not released by his creator and instead was sealed away in a capsule, initially believed to engage Dr. Light's masterpiece creation, Mega Man X, in battle in the future. Decades later, in the early-22nd century, he was awakened by a group of Reploids prior to the first Mega Man X game.

When he was first activated, he awoke as a Maverick and destroyed all intruders who had dared to enter Wily's lair and was later cornered by Garma's Maverick Hunter unit inside an unknown facility, however at the cost of a total loss of said unit. Not wanting to get anymore comrades endangered by the powerful enigmatic Maverick, then-Hunter 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 and a 'W' symbol appeared. Sigma punched this crystal which shattered it, defeating Zero (and subsequently passing on the Maverick virus). He was then brought to Dr. Cain, who analyzed him. After that, Zero recovered from his battle with Sigma and was placed under Sigma's watch, Zero did not show any signs of Maverick behavior and was enlisted into the Maverick Hunters' 17th Elite Unit.

The Day of Σ
As part of the 17th Elite Unit, Zero became an excellent Maverick Hunter and was soon ranked SA-Class, the highest rank the Maverick Hunters had to offer at that point of time. It was during that time in which he met X for the first time who was also part of the 17th Unit, even though he was only ranked B-Class due to his hesitation on the battlefield. The two became friends and partners and worked together whenever they could. Zero soon became a somewhat mentor to X.

Soon afterwards, a series of Mechaniloids going berserk occurred in Abel City, the city in which the Hunter Base at that point was located. During the course of the investigation, it was Zero who eventually uncovered the identity of the person responsible for the attacks, which was none other than Sigma himself. Zero realized this after analyzing various locations which were seemly connected to the attacks, and by looking over the bodies of defeated Reploids, which were all taken down with a single blow directed at a weak spot. There had been only a very few number of Reploids with such perfect skills, including Sigma. Also, the damage the defeated Reploids had taken was caused by a beam saber, and not by range-weapons, which ruled out the previously suspected Vile.

Even though Zero managed to block Sigma's first attack, he was soon overwhelmed by Sigma and was used to pressure X into surrendering. To get Zero out of his way, he was struck by Sigma's beam saber and later abandoned while Sigma held X captive and launched a missile attack on Abel City. Some time later, Zero regained conscious and found X all alone in the facility, heavily damaged. He then brought him back to the Hunter HQ.

Mega Man X / Maverick Hunter X
After Sigma's declaration of Reploid Independence on July 4th 21XX (June in the US manual of the original game), dubbed "The Day of Σ", Zero, who at that point was the highest ranked member of the Hunter organization, became the new leader, and he and a repaired X fought together against Sigma's uprising rebellion. Zero saved X during a Maverick attack at the Central Highway from Vile. After that, the two split up, with X's task to slow down the Maverick activities in nearby areas while Zero himself was on recon duty at Sigma's fortress.

They eventually met there and together invaded the fortress. Here, they encountered Vile for a second time. Zero was captured by Vile and imprisoned in a cage (in Maverick Hunter X however, Zero was left unconscious by Vile as a bait for X). When X was also defeated by Vile, Zero managed to break free and destroyed Vile's armor by firing a charge shot from point-blank range, which was a successful, yet fatal action. Afterwards, Zero handed his Buster Parts to X (only in case X hadn't obtained the Buster Upgrade from the Dr. Light capsules) and encouraged him to continue to fight before ultimately dying in X's arms.

Mega Man X2
After Sigma had been defeated, the Hunters tried to salvage whatever remained of Zero from the sunken fortress and found Zero's Control Chip (which serves as Zero's "brain" and consciousness) which had miraculously survived the destruction of the body. However, the Hunters were incapable of creating a new body for Zero because they were unable to analyze Zero's unique body structure.

Six months later, a group of three Mavericks, calling themselves the "X-Hunters" (Counter Hunters in Japanese), contacted the Maverick Hunters and claimed to be in possession of all parts of Zero. The X-Hunters challenged X to a battle in order to win Zero's remains. (The Japanese version of the game however claims that they actually rebuilt the parts and did not use remains from the previous game. It was Serges (Sagesse in Japanese) who constructed the parts and upgraded the body with the specs Zero was originally intended to have, including reinforced shoulder plates and Z-Saber).

X, who didn't want his friend to be in the hands of Mavericks, accepted and eventually recovered Zero's head, body and foot parts. Eventually, Zero was reconstructed by Dr. Cain (now completed with his signature Z-Saber and enforced shoulder plates) and assisted X in destroying the base of the resurrected Sigma. Trying to fool X however, Sigma had constructed a doppelgänger of Zero with Black Armor which he claimed to be Zero, however this copy was destroyed by the real Zero.

As a non-canon scenario in X2, in case X wasn't able to retrieve all of Zero's parts, the X-Hunters would steal any parts X had previously collected from the Hunter Base, as well as Zero's Control Chip. Zero would then be reconstructed by Sigma as a Maverick and was fought by X prior to his encounter with Sigma. After being defeated, Zero would regain his consciousness and assisted in destroying the base.

Mega Man Xtreme
Zero played only a minor role in the story of this game. After X managed to escape the digitalized version of the Central Highway, Zero would inform him that Mavericks had hacked the Maverick Hunters' Mother Computer, stealing and corrupting data and allowing other Mavericks to run wild everywhere. While X was digitalized again and sent back into the Mother Computer to destroy the protection systems that were needed to be taken out to shut the computer down, Zero would handle Maverick attacks in the real world. Also, later during the game, X would be able to find four capsules within the digitalized areas, the Zero Scrambles, which allowed him to "summon" Zero to perform an attack or move. However, this was only combat data of Zero and not the real one.

Mega Man X3
Zero only played a minor role during the Doppler incident. He and X defended the Maverick Hunter Base from Dr. Doppler's Maverick forces and saved X from the traitor Mac. Zero would here and there be of help for X as he could summon him once a mission (this marked the first time Zero was playable, but he wasn't able to fight bosses), using his Z-Buster and his Z-Saber. While trespassing Doppler's secret lab, he saved X from a spike room booby-trap with REX-2000.

If Zero was summoned during the second stage of Doppler's lab at a specific point, he fights a Mosquito-like Mechaniloid which was destroyed by him, however the Mechaniloid managed to hit Zero in a last resort attack. The crash of the Mosquito damaged Zero's power generator which forced him to return to Hunter Base to have repairs done. Because this made him unavailable for the rest of the trip, he would then lend his Z-Saber to X.

Mega Man Xtreme 2
In Mega Man Xtreme 2, Zero paired up with X to investigate the resurgence of previously retired Mavericks. Technically speaking, this is the first time Zero was able to fight bosses. It also introduced his famous three hit saber combo, as well as his ability to learn special techniques as opposed to weapons. He battled Gareth, partner of Berkana, who was reviving the dead Mavericks. Afterwards, Zero aided X in the final battle against the resurrected Sigma.

Mega Man X4
Zero's first appearance as fully controllable character with his own story also marked his most tragic point in life. At the beginning of the game, Zero encountered his creator within his dreams who ordered him to finally obey his orders and fulfill his destiny by destroying his nemesis' greatest creation. When he awakened of the nightmare, he was immediately dispatched to the Sky Lagoon colony which had been attacked by Mavericks. Repliforce was also confronted at the scene, claiming to assist the Hunters in evacuading the city, however both factions didn't trust each other for a moment and as a request for interrogation was declined, the Great Repliforce War broke out.

When the Repliforce was labelled Maverick after the Sky Lagoon incident, both X and Zero were assigned different missions to gather information about Repliforce's coup and to cut off their support lines. Iris, who was by now Zero's girlfriend, assisted Zero on his missions as being his operator, like during the Erasure incident. However, Iris herself was part of Repliforce while her brother, Colonel, was Repliforce's second-in-command and therefore an imminent target for the Maverick Hunters. Iris didn't want the two of them to fight, ravished between her love for Zero and her love for her own brother. When the two of them battled in the Ceremony Hall of Repliforce's command center, it was Iris who stopped the two Reploids from terminating each other by begging her own brother to stop since Zero had previously saved her life after the Sky Lagoon had crashed down. Colonel, who had always regarded Zero as a friendly rival, backed off. Zero on the other site however stated that someone had to stop Repliforce at all costs, much to the grief of Iris.

When Repliforce's coup began, Zero rushed to the space port to stop the ascension of the military troops to the newly constructed space station of Repliforce, Final Weapon. There, he battled Colonel, this time not holding anything back, just like his former friend with Zero being the victor of the fight. After that, he traveled to Final Weapon where he was, much to his surprise and horror, encountered by Iris, who was blinded by her grief of the loss of her brother and anger for her own lover killing him. She had salvaged Colonel's Control Chip from his remains, fusing it with her own programing, thus resulting her body to transform into a massive Ride Armor like combat form which Zero was forced to battle. Even though he didn't mean to, Zero damaged the exterior power core of the structure, resulting in the destruction of the armor. He hurried to Iris' body, however, it was too late to save her. Whispering to Zero that she did all this because she wanted to live in a world for Reploids only together with him, she died in his arms and Zero, who was totally overthrown by the pain, began questioning his own reasons for fighting and the means of his own existence (he yells "WHAT AM I FIGHTING FOR!!!" at the end, which, thanks to the game's low grade voice acting, has become a popular quote among many internet users). Filled with anger, he confronted General, the leader of Repliforce, defeating him in battle. Upon the end of the fight, General realized that someone had taken over the control over Final Weapon, aiming it at Earth. Zero went to the control facility, only to find Sigma there, who revealed their pasts to him (back when Sigma was still a Maverick Hunter and Zero was first seen as a Maverick). After Zero had destroyed Sigma and the General had sacrificed his life to make the Final Weapon self-destruct, Zero escaped the destruction in a small spacecraft, thinking about what he had done. He hadn't been able to save anyone he cared about. He had killed his own friend Colonel, the General who in the end had only been manipulated by Sigma and his own lover Iris. Questioning whether or not Reploids would be supposed to be Mavericks afterall, he returned to Earth.

If the game was played by X, Zero would only appear at the very end of the story, contacting X from Hunter Base upon his return to Earth by spacecraft. X, wondering what would happen if he turned Maverick, asked Zero to take care of him if that would ever happen. Confused, Zero didn't answer to X request, although he seemly realized X's seriousness about the topic and the eventual battle between him and his best friend.

Mega Man X5
Zero played a pivotal role in Mega Man X5. The space colony "Eurasia" was set to impact the Earth, recently being coated in a large breakout of the Maverick virus, which would cause catastrophes of unimaginable proportions. In the meantime, X and Zero faced Sigma on Earth and easily defeated him, however, Sigma lost on purpose to spread the Sigma Virus around the world. Due to this, thousands of Maverick Hunters turned Maverick, yet, the fall of the colony posed to be a bigger threat. In order to stop the impact of the Eurasia, X and Zero both would gather several enhancement parts to power up an old energy cannon, known as "Enigma" (Enigma is German for mystery, an odd name for a gun) to destroy the colony before it could devastate the planet. While doing so, Zero noticed his strange reaction towards the Sigma Virus. While others, like X, got hurt by being surrounded by the virus, he himself actually felt energy growing inside himself, multiple infections of Sigma Virus ananomalies even turned him invincible for brief period in time. Behind the scenes, Lifesaver informed Hunter General Signas about his concerns regarding Zero, but also that there might have been a chance to develop antibodies from his DNA to cure the Maverick/Sigma Virus. Yet, the accomplishment of the Enigma was rendered priority one.

However, it didn't matter how much the cannon was powered up, a complete destruction of the Eurasia was impossible and only delayed the impact (in the game it's possible to destroy Eurasia with only the cannon, but story-wise it didn't work). As a last resort action, a Space Shuttle was readied to be launched and be directed right into the colony to have have it self-destruct right at the Eurasia's core. The shuttle would be operated by Zero and the operation succeeded, however debris would still rain down on Earth. Zero was later rescued by the Hunters but the peace only lasted for a short time as a new threat arose from the debris of Eurasia.

A new virus, merged from the virus inside the colony and the Sigma Virus, called the "Zero Virus" by Alia, had begun to effect the impact area. The area flooded by the new virus was strangely deformed and was filled with Zero Virus anomalies that even resembled Zero. Also, strange Mavericks were found in the area, bosses that actually resembled earlier bosses such as the Shadow Devil and Rangda Bangda. The closer X and Zero got to the source of the virus, the higher Zero's viral infection level rose, yet not showing any Maverick behavior. Not wanting Zero to become a Maverick, X would fight his friend in order to have him being brought back to Hunter Base. Eventually, the battle would end in a draw. Upon seeing X and Zero both being completely exhausted after their battle, Sigma would reveal himself to destroy them. However, Zero managed to prevent this, protecting X and himself and forcing Sigma to retreat.

If the one who would pursue Sigma was Zero, Sigma would reveal to him that he let the colony fall on Earth solely to purify Zero's body with the virus to clear his mind and awaken his true self. Upon defeating his first form, Sigma would also reveal to Zero that he met an "Old Man" which knew a lot about Zero and his past, caring for him like a father and that it was that man's suggestion to flood Zero's body with the Virus to awaken him. After defeating his large battle body form, Sigma would then try to take X, who was still left unconscious at the scene of his battle with Zero, down with him. Zero would take most of the hit, majorly damaging him. The remains of Sigma attacked Zero and X one final time, impaling both of them in the chest area but was then completely destroyed by Zero who gained consciousness briefly and fired a charge shot at him from his buster.

Exhausted and damaged from the battle, Zero finally realized that he was going to die and while in a state between life and death, he began recalling memories of his creator and his true purpose of existence. Yet, his memory circuits began to seize function. After recalling is memories of Iris and apologizing to her, Zero asked X to live for him, bringing peace to the world. After X was saved and repaired by the spirit of Thomas Light, X searched for Zero, but found nothing but his Z-Saber, which he kept in order to honor his fallen friend.

As a non-canon scenario, if the Shuttle Operation was not successful, the large amounts of the Colony Virus, together with the Sigma Virus Zero had already been infected with from Earth, would awaken Zero upon crashing on Earth, thus challenging X to a battle. His mind now cleared and caring about nothing but his mission to fight X, Maverick Zero battled X, resulting in a draw. After taking massive damage during the fight, as Sigma revealed himself and prepared to destroy X, Zero regained conscious and he jumped into the line of fire, protecting X with his body. When X destroyed Sigma in this scenario and was damaged badly, Dr. Light would appear to save him, however he made him forget about Zero and would implant a protection inside X's mind so no information about Zero would be accepted.

Originally, Mega Man X5 was supposed to be the final game of the series and Zero getting killed in the course to make way for Inafune's original plot of the Mega Man Zero series. However, Mega Man X6 was produced unbeknownst to him and without his approval, and since the plot of X6 involved Zero once again, he had to modify his Mega Man Zero concept in order to not make the story more confusing.

Mega Man X6
In Mega Man X6, the mad scientist Gate began tampering with Zero's data. By studying a piece of Zero's body found in the debris, Gate created the new Nightmare Virus, a discolored clone of Zero (called "Zero Nightmare"), and the near-invulnerable Reploid, High Max. X, taking the assault on Zero's reputation personally, set out to investigate. Upon destroying the Zero Nightmare, X is reunited with his friend, mysteriously repaired and carrying a brand new Z-Saber. Together, X and Zero set out to defeat Gate and the imperfectly resurrected Sigma. Who exactly repaired Zero was never directly stated. Dr. Light, who repaired X at the end of X5, denied knowing who repaired Zero. Some believe it is Gate's ally, Isoc, as he is the only Reploid who claimed to have seen Zero before X found him, and he demonstrates an odd obsession with Zero, even laughing joyously when Zero defeats Gate's own men, but in this very cutscene Isoc says, "Now that I know you are alive I can capture you at anytime." If it was Isoc, he would have known Zero was alive. Again, in this game Zero has his Z-Buster with slight differences: It takes a bit less time to use than in X5 and it seems to do more damage at a close range.

Zero's ending in this game helps to mend the storyline between the Mega Man X and Mega Man Zero games. It shows Zero being sealed to remove a component from his body (presumably something having to do with the virus' influence on him, and/or his original murderous persona). This was originally going to show that the X series had ended, but fans loved the series so much, Inafune was forced to continue, making many people believe that this is either a glimpse of the future, or non-canon. However, recently revealed backstory information in the Japanese Mega Man Zero Sourcebook "Rockman Zero Official Complete Works" has revealed that this ending is indeed canon, takes place in an unspecified time period beyond the last X series game, and is in fact considered the first of 2 different times when Zero sealed himself away (the second time being after the Elf Wars, when he sealed himself away once more in the Rockman Zero TELOS drama tracks, and was then finally reawakened in the Zero series).

Alternatively, it is possible to clear Mega Man X6 without ever finding Zero. In this event, cutscenes show that Zero is indeed alive, but X and the other Maverick Hunters never find him. Zero leaves on his own, stating that there's something he needs to take care of. Like the alternate ending to X5, canonically, this ending does not happen.

Mega Man X7
In Mega Man X7, Zero is responsible for the bulk of the Maverick Hunter workload due to the fact that X has recently refused to battle for any reason, due to his doubts about the Hunters' violent methods. Zero captures a mysterious Reploid, Axl, who has just recently abandoned the vigilante group Red Alert. Axl assists Zero in stopping Red Alert's rampages, and eventually X rejoins them. After the battles, Zero has nightmares of X attacking him, out of obsession for eliminating Mavericks (possibly foreshadowing the rise of Copy X in the Zero series). Mega Man X7 signified a few changes to Zero's gameplay. His Z-Buster was eliminated altogether, and in addition to learning new attacks from defeated Mavericks, Zero can also gain other melée weapons to replace his saber. This tradition would continue through Mega Man X8 and Mega Man X: Command Mission.

Mega Man X8
Zero continues to work with X and Axl, who is now working with the Maverick Hunters, in dealing with new threats in Mega Man X8. One of the new navigators, a purple-haired girl named Layer, has shown a romantic interest in him; Zero has not returned the emotion however, simply keeping the relationship professional. Zero's memories of the virus incident from Mega Man X5 continue to haunt him, fueling his hatred towards Sigma. Upon confronting him, Sigma confirms that Zero is the original carrier of the Maverick Virus, which was transferred to Sigma prior to the game Mega Man X (presumably it happened when Sigma shattered Zero's head gem as X4 depicted, though the unlockable animation "Day of Sigma" in the PSP remake of Mega Man X has put a few doubts on this). This information was long-since stated in Japanese sourcebooks, but was never before made officially available to the public in other regions.

Mega Man X Command Mission
In the game Mega Man X: Command Mission, Zero is sent along with X and another Reploid, Shadow, to investigate Reploid uprisings in Giga City. Zero is separated from X after Shadow betrays them, and presumed dead, until he reappears some time later and attacks one of the rebelling Reploids in a mechaniloid factory. At this point, Zero is joined by X, Axl, and a number of other Reploids that X assembled to assist him. With Shadow's betrayal still fresh in his memory, Zero is unwilling to trust X's new friends, and promptly decides to work alone. However, one of the Reploids, Spider, risks his life in Zero's defense. After this, Zero decides to rejoin X's group permanently, although Spider eventually turns on them and reveals himself as Colonel Redips. He had hid his true identity from the group by using a replica of Axl's DNA change, hinting toward the possibility that Spider could have actually existed at one point (since Axl needs to take DNA from a Reploid in order to change into it).

The Elf Wars
At some unknown point after his mission on Giantis, Zero realized that he carried the virus inside him and spread it all over the world during his missions as a Hunter. Thinking that the world wouldn't be safe as long as he was still active, Zero admitted himself into a research institute, in order to get rid of the virus within him that caused Reploids around him to go Maverick. At the same point, a project was started to analyze Zero as it had been revealed previously (during the Eurasia crisis to be exact), that Zero actually reacted positive to the Sigma Virus, therefore might hold anti-bodies for the infection. Zero was sealed away and brought to a government lab. At some point, Zero's mind was extracted from the body, possibly for security measures in case something would go wrong while researching it.

For an unknown amount of time, Zero's body was studied by government researchers. One of them, an unnamed female ancestor of Miss Ciel, managed to create the "Sigma Antibody Program", a Cyber-elf capable of reverting the devastated programming of infected Mavericks and therefore destroying the virus completely. This Cyber Elf was the Mother Elf.

However, weapon researcher and DNA revival specialist Dr. Weil, who worked in the lab as well, planned a different way of dealing with the Mavericks, and was unsatisfied with the result. Stealing Zero's mindless body and the Mother Elf, Weil started a horrible conflict that would ultimately cost the lives of 90% of all Reploids and 60% of all humans. This four-year-long period of war was later dubbed the "Elf Wars".

Weil, who used the Mother Elf (now known as the Dark Elf) and copies of her, known as Baby Elves to gain control over Reploids all over the planet, ordering them to destroy each other, worked on Zero's body, manfacturing an exterior armor around him which boosted the body's specs to its limits as well as granting him the ability to control all Reploids at the same time when combined with the Dark Elf and creating a new consciousness for the body loyal to him: Omega.

When the Elf Wars were in their fourth and final year, Zero reappeared on the battlefield, given a copy of his old body (however, it is still unknown who created the body, but it is presumed it was Ciel's ancestor). Zero managed to infiltrate Weil's laboratory and steal the Dark Elf from Weil. He then ordered every Reploid in the Dark Elf's range to turn against Weil. At that point, Omega was released onto the battlefield, along with a few Mechaniloids, to defeat X and Zero and retrieve the Dark Elf. Zero, who by that time had realized Omega was using his original body, defeated him together with X by using the Final Strike, disabling the massive Reploid.

After the war had ended, Zero decided to seal himself away again, this time, forever. Though X tried desperately to stop his friend from sealing himself another time, the sealing process had been gone too far to stop it. Zero told X that, as long as he was still around, the bloody history would repeat itself over and over again. Before the seal was complete, he encouraged X that this was the right way and that he wanted to believe in the humans as X believed in them. With these final words, Zero's seal was complete.

Mega Man Zero
At the beginning of Mega Man Zero, Zero was discovered in suspended animation by a human scientist named Ciel, who leads a band of Reploid freedom fighters. Ciel used the Cyber-elf Passy to revive Zero, who in turn saved Ciel from the forces of Neo Arcadia. 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 weaker clone of the real X, was in charge of this policy. Zero agreed to join Ciel's team in fighting this oppression of Reploids. Zero would then go on to defeat Copy X's 4 Guardians as well as destroying Copy X himself.

After the battle with Copy X, Zero was declared missing by the Resistance, after the Neo Arcadian Core was destroyed. In truth, Zero is traveling in the desert, where he spends one year evading the forces of Neo Arcadia before returning for the events of the second game.

Mega Man Zero 2
At the beginning of the Mega Man Zero 2, Zero is still traversing the harsh desert, and still hunted by Neo Arcadia. After one battle with the Neo Arcadian Forces, Zero finally succumbs to his injuries, and collapses. When he wakes up, he is now in the new Resistance Base, brought there by unknown means (which was revealed to be Harpuia), and meets the new members, including a new commander, Elpizo.

Later on, Zero learned of what had happened before his sealing; Sigma and his 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 rogue Resistance commander, 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.

Mega Man Zero 3
In Mega Man Zero 3, Dr. Weil and Omega reappear and seize control of Neo Arcadia and the Dark Elf. Weil reveals (and X confirms) that the body Zero currently inhabits is a copy, even though he still has his real soul. This led to a final battle between him and Omega, who is revealed to contain the "original" Zero. With the help of the X, the Guardians, and even the Dark Elf who breaks free of her curse, Zero manages to destroy Omega once and for all, but Weil escapes. The Dark Elf, now called Mother Elf, roams free. However, X now cannot roam in the real world any longer. Before X goes away, he tells an unconscious Zero to always protect the peace between Reploids and humans.

Mega Man Zero 4
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 Variant drones (remodelled Mechaniloid 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, and to find out the whole truth about Weil.

After repelling an attack on Area Zero by the eight Einherjar warriors, Zero heads for the space station "Ragnarok," created by Dr. Weil, and fights him in two battles. After the first battle, the space station is damaged and begins to fall to Earth. Ciel tells Zero that he can either return to Earth at that moment, or become stranded on the station due to increasing transporter interference. He passes the offer to come back and proceeds to finish Weil off in their second battle, ultimately sacrificing himself as the death of Weil's last form causes the station to explode (though the Mega Man Zero official complete works, which is canon, mentions that his fate is unknown). Zero's final act opens the eyes of many, and brings peace between the Reploids and humans left on Earth.

Mega Man Zero: Complete Works Bio
The legendary Reploid who fought valiantly and was known as a hero during the Maverick Wars. Though the soul is indeed that of Zero, the body that Ciel found him in was a copy of the original. Zero's original body, which had caused much damage during the Elf Wars, had been sent into space, and is now known as Omega. But Zero's new body, showing at least as much if not more potential than the last, has saved the world twice over from the evil intentions of Omega and Weil, the man controlling him. Zero was last seen in space. His current whereabouts are unknown.

Vile's Incident - Eden Dome, it's Sin and Rebirth

 * Under Construction

This is a special feature from one of the Remastered Tracks Rockman Zero disks.

Mega Man ZX
Zero makes a major cameo in the Nintendo DS game Megaman ZX, as Biometal Model Z, which was modeled after him. Omega Zero also appears as an optional boss in Area N-1. Defeating him in Normal or Hard will allow access to a rock which gives you Model OX. Although Biometal Z is not usable by itself it can be combined with Biometal X to form Model ZX, the title character.

Zero appears in a flashback scene in Vent's story, where Prairie explains that her sister was a human (obviously referring to Ciel) that defended the Reploids. The scene then shifts to a view of Zero and Ciel looking at an army of Pantheons. Zero is mentioned when (again in Vent's storyline) Prairie explains that Model W is the spirit of Dr. Weil, and that the last time Dr. Weil had appeared, he was stopped by Zero (although the game never addresses Zero by name, simply calling him "a hero").

Model Z makes another cameo appearance in Mega Man ZX Advent. After Ouroborous starts falling apart, Model Z decides to take down the enemy Mega Men by himself, and allows Aile/Vent to go rescue Grey/Ashe, who fainted after the battle. Model Z manages to freeze the four Biometals, which freezes the users themselves. The conclusion of the battle is unknown, since Aile/Vent did not mention anything about Model Z during the ending. However, if the player beats hard mode, then a secret ending shows the 4 Enemy Mega Men alive and well, in their MegaMerged form.

Other appearances

 * Zero (in Mega Man Zero form) appears as a hidden playable character in the games SNK vs. Capcom: SVC Chaos and Onimusha Blade Warriors.
 * In SNK vs. Capcom, Zero is a mid-boss. In his story, it appears he travels back in time, as he is the only Reploid in the time frame and Ciel is the only person outside the time frame who is able to communicate with him. Because he appears in a collaboration game between Capcom and SNK, his story is considered non-canon to the Mega Man series. When playing as Zero, a WARNING signal will appear on some pre-battle introductions, including Shin Akuma and a Zero mirror match itself.


 * A poster of Zero, in his "Black Armor", can be seen in one store of the game Mega Man Legends 2, where he is described as some sort of comic book hero. (Image)


 * Zero has a cameo appearance in Higsby's shop in MegaMan Battle Network 3 White version. In the Blue version of the game it's a poster of SharkMan.


 * An actual NetNavi bearing the name Zero appears in the game MegaMan Network Transmission and the anime Rockman.EXE Stream and Beast, and is one of the few characters from the Mega Man X series to receive a NetNavi counterpart. Here, he appears somewhat identical to Zero, but with a more demonic appearance, as he does not appear to have a human face and breathes in a manner similar to Darth Vader. Like his X counterpart, Zero still has an affinity for blade weapons and also serves as a virus being. However, unlike his counterpart, this Zero is the virus, but he still follows orders without question. In the conclusions of the series, Zero begins to show compassion, and even sacrifices himself in Beast+. However, the canon ending of Transmission gives Zero a NetNavi identity as Zero.EXE, now free to roam the Internet and explore the world to make new friends, though his activity is to be monitored by Science Labs, where he now thrives. In addition, players can receive a Z-Saber chip for MegaMan Battle Network 4 by linking up with another Game Boy Advance that has Mega Man Zero 3 inserted.

Arsenal

 * Main Article: Zero's weaponry

Trivia

 * Zero was originally intended to be the main protagonist of Mega Man X, according to Keiji Inafune, Mega Man's creator. However, Zero was turned into a secondary character because Inafune feared Zero's look would not be approved by fans as a true Mega Man. He would eventually gain his own game series on the GameBoy Advance, Mega Man Zero, making him the only character in the franchise who isn't a Mega Man incarnation to gain his own official series.
 * Although not a Mega Man incarnation, Zero is essentially a successor to the previous Mega Man, X, hence his own series. This is ironic because of Wily's purpose to creating Zero, which still remains a mystery, as well as the fact that the two have a sort of mentor-student dynamic during the first Mega Man X title.