Zero

"Even if we Reploids are destined to join the scrap heap when that evolutionary step does come about...We still have to fight... Not only against Mavericks, but against our own destiny as well."

- Zero

"Target destroyed. Returning to base."

- Zero's victory

Zero (ゼロ) is the deuteragonist of the Mega Man X series, the main protagonist of the Mega Man Zero series, and also an important supporting character in the Mega Man ZX series as the Biometal Model Z. He is the successor of Bass and the greatest creation of Doctor Albert W. Wily. A high ranking Maverick Hunter in the X series, and a legendary freedom fighter in the Zero series, he's a die-hard warrior who doesn't hesitate to take action. However, behind his cold and emotionless attitude lies a wounded soul.

Appearance
Zero prominently sports a red color scheme. In his first appearance, Zero's armor was round for the most part with a red, black and white color scheme and white shoulder guards with a stylized "Z" insignia on his left shoulder. His helmet is horned and features a sharp blue crystal in contrast to his partner, X's smoother red gem. Perhaps his most striking feature is his long blond hair that flowed freely about in a samurai like hairstyle, making Zero appear fiery in comparison to X's more cool and consistent blue scheme.

When Serges of the X-Hunters reconstructed Zero's parts, he upgraded the body, including reinforced shoulder plates and Z-Saber. Other enhancements were the improved arm guards (in contrast to the original streamlined ones) and leg joints, with improved mid-air dash thrusters and gold-plated covers, along with thicker and bigger chest armor. A small "backpack" device is also added as both storage and recharging unit for the Z-Saber. The first version of Zero was apparently just an "incomplete" prototype, since this version is the outline shown in the blueprints in Mega Man 2: The Power Fighters.

Like X, Zero's power source is solar energy. His body material is comprised of a Titanium Z alloy, and is equipped with peculiar mechanisms called the Z-Brain (the head lens) and the Z-Heart (the chest lens), which conceal an unknown power.

Zero's X1 and upgraded designs in TEPPEN are largely the same, with his limbs and joints appearing more robotic and having panel lines on his face. In his Maverick state, glowing turbines underneath his gauntlets become visible and his crystal turns purple with a letter W, similar to his flashback appearance in X4.

Personality
Prior to his encounter with Sigma and becoming a Maverick Hunter, Zero was extremely violent and maniacal. He often unleashed feral screams and laughed psychotically, especially during his battle with Sigma.

Outwardly, Zero appears cold and emotionless to others, even towards partners X and Axl. However, it is shown that he has the capacity to care for others. Zero keeps his cool under most circumstances. No matter what his enemies do to him, he is always able to come up with a retort.

Zero has often displayed a tendency to sacrifice himself for the sake of others. He also shows distaste for innocent deaths. This is evidenced in his fighting against Neo Arcadia's ruthless policy against Reploids in the Zero series; he even personally promised to Sage Harpuia that no more Resistance soldiers would come to harm as long as he was around.

Even though Zero does not openly show it, he too seems to long for peace between humans and Reploids. However, he has said that he doesn't have any problems fighting, unlike his more pacifistic friend, X. Another notable trait of his is that, despite his great power, Zero views X as the superior Maverick Hunter and considers him a hero, though he doesn't see himself as such. A prime example of this show of respect was in Zero's ending in Mega Man X6: when the researcher who was performing his sealing process asked what would happen if the world faced another crisis; Zero firmly said that the world is in good hands (X's), even when he is gone.

He seems to have a great pride in his position as a Maverick Hunter, and even being the most serious of the three heroes from the X series, Zero has a soft and friendly side giving quick smiles to his friends, especially X. He can also have a breakdown in the moments of his most difficult losses, like when Iris died.

Origin
Zero was created by the late 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 will 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 to that of Bass or Mega Man 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". 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.

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 an unknown facility, and Zero destroyed Garma's unit. Not wanting to get any more comrades endangered by the powerful enigmatic Maverick, then-Hunter Commander Sigma himself challenged the red Maverick 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 this crystal, shattering it and defeating Zero, and Sigma was infected by Zero's Maverick Virus. Zero was then brought to Dr. Cain, who analyzed him. After that, he recovered from his battle with Sigma and was placed under Sigma's watch. Zero did not show any more 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 A-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 somewhat of a 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. The blows that 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 and was used to goad X into attempting to kill Sigma, which would have killed Zero in the process, to see whether X really could hesitate. Upon seeing that X indeed does hesitate, Sigma slashed Zero with his beam saber and left him while he 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 Hunter HQ.

Mega Man X/Maverick Hunter X
After Sigma's declaration of Reploid Independence on July 4 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 rebellion. Zero saved X during a Maverick attack at the Central Highway from Vile. In Maverick Hunter X, Zero also responded to Vile's question about why Zero would aid a B-Class Hunter like X by informing Vile that he's nothing more than a Maverick at the present. 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 rendezvoused at the outskirts 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 bait for X). When X was also defeated by Vile, Zero managed to break free (or regain consciousness, as was the case in Maverick Hunter X) 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 Light Capsule) and encouraged him to continue to fight before ultimately dying in X's arms (Maverick Hunter X also has Zero remarking on the irony of his actions in saving X leading to his death when he earlier told X not to be so careless ).

Vile Mode
In Vile Mode, unlocked by completing the main game in Maverick Hunter X, Zero's characterization was similar to the main game, including saving X from Vile. However, instead of chasing Vile off, Zero instead retreats with an injured X. X and Zero later reappears as the final bosses at Sigma's Palace Stage 3, where he learns that Vile is in fact working against Sigma as well as fighting X and Zero. He ends up severely injured by Vile, although he eventually managed to sneak up and grab Vile's leg and pin him before he could deliver the final blow against X, also referring to Vile's earlier rant about X "changing the world" as "maverick talk," also grounding Vile so he'd be caught in X's charge shot. It is unknown if Zero managed to survive the charge shot that critically wounded Vile, or if, like in the main game, Zero also ended up destroyed in a sacrificial effort to help bring Vile down.

Mega Man X2
After Sigma's defeat, 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 his unique body structure.

Six months later, a group of three Mavericks, calling themselves the "X-Hunters" (Counter Hunters in Japan), contacted the Maverick Hunters and claimed to be in possession of all of the rest of the parts that would be required to rebuild Zero. Although the American translation of the game fails to reveal how the X-Hunters gained the parts, the Japanese version elaborates with the claim that Serges (Sagesse in Japan) added these parts as they were planned additions made by Dr. Wily. The X-Hunters challenged X to a battle in order to win Zero's parts.

X, who didn't want his friend in the hands of Mavericks, accepted and eventually recovered Zero's head, body, and foot parts. Eventually, Zero was reconstructed by Dr. Cain (including the upgrades that Serges had provided) and assisted X in destroying the base of the resurrected Sigma. Trying to fool X however, Sigma had constructed a doppelganger of Zero with Black Armor which he claimed to be Zero; however, this copy is quickly destroyed by the real Zero. This is the canon ending. In the Japanese version of the game, Sigma mentions just before his death that Zero is the last of "Wi...numbers", giving the first hint that Zero is the last of the "Wily numbers", or advanced robots built by Dr. Wily. The American version also gives a vague reference to Zero being the "last of the Doctor's creations."

As a non-canon scenario in the game, if X couldn't 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 as a Maverick and was fought by X prior to his encounter with Sigma. Upon being defeated, a very wounded Zero would awaken from his Maverick stasis and assist X in destroying the Central Computer base. His weakness in this battle is the Speed Burner.

Mega Man Xtreme
Zero played only a minor role in the story of this game. After X managed to escape the digitized 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 digitized 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 digitized 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


The beginning of the Doppler incident finds Zero and X back in their respective commands of the Maverick Hunter Forces. Dr. Doppler's Mavericks lead an attack on the Hunter Base, and X and Zero are forced to return to the base to defend it. Zero joins the Hunters defending the base outside while X ventures into the base. However, when X is captured by the defector, Mac, Zero immediately leaps into the chaos inside the base to save his best friend from the traitor's clutches, being a playable character for the first time. Zero's default weapon is the Zero Buster, however, upon fully charging until he turns green, he will unleash 2 fully charged shots followed by a devastating blow with his other weapon, the Beam Saber.

After completing the Opening Stage, the player can call on Zero anytime by pressing the R-button in the Start Menu, however, Zero adheres to a certain set of rules. He is only able to maneuver through regular parts of the stage and will automatically be replaced by X upon reaching a gate before a boss or sub-boss. The player also cannot die in game as Zero. If Zero dies, a cutscene will appear where Zero will talk about being damaged and will be unusable for the rest of the game, however he will still appear in the Doppler Stages to assist X during a sub-boss encounter, taking care of a booby-trap while X destroys the REX-2000.

There is also a secret in game that will allow X to acquire Zero's saber. If during completion of the game the player locates Vile MK-II through a teleporter located in either Crush Crawfish's stage, Volt Catfish's stage, or Blizzard Buffalo's stage and defeats him with one (or both) the Spinning Blade and Ray Splasher, Vile will be destroyed, changing the final boss of the second Doppler Stage as well as affecting the level throughout. Upon entering the 2nd Doppler Stage, the player will notice that the Head Gunners are now customized and are twice as difficult to defeat. If the player switches to Zero before entering one of the boss chambers which is normally an empty hallway, a robot called Mosquitus will appear, the only sub-boss that Zero can battle. This enemy is actually very easy to dispatch, however, when defeated, it will crash-land on top of Zero and explode. X will then return and Zero will explain that a few of his power cells have been damaged. He will then hand over his saber to X and then head back to Hunter HQ for repair. Note that this has the same effect in game as dying with Zero, except that if X leave the game and return, Zero will not reappear within the Doppler Stages as he does when recovering from a standard in-game death. It is also worth noting that if leaving the game and returning with a password, Mosquitus will still appear for X to defeat.

After defeating Doppler's eight Mavericks it begins to become clear Sigma is once again behind the whole incident. After defeating Sigma, he will attempt to possess X. But before he can, Zero appears and hits Sigma with his saber, where he uploaded Doppler's Anti-Sigma Virus-program, believing that it is the only thing that works against him. Sigma seemingly explodes as Doppler's lab self-destructs. If player loses Zero during the game, Doppler appears instead.

Mega Man Xtreme 2
Zero appears as a playable character with gameplay similar to Mega Man X4. Zero paired up with X to investigate the resurgence of previously retired Mavericks, investigating Laguz Island. 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 a fully controllable character with his own story, which also marked the most tragic point in his life. It also introduced his three hit Z-Saber combo, as well as his ability to learn special techniques as opposed to X's Special Weapons.

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. When he awakened from the nightmare (which is implied to have happened before), 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 evacuating the city; however, both factions didn't trust each other, and, as a request for interrogation was declined, the Great Repliforce War broke out.

When the Repliforce was labeled 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 assisted Zero on his missions as his operator, like during the Erasure incident from Mega Man Xtreme 2. 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, torn between her care 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 hand, stated that someone had to stop Repliforce at all costs, much to Iris' grief.

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 the 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 Zero killing him. She had salvaged Colonel's Control Chip from his remains, fusing it with her own programming, 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, and that he could live in that world too. 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. Filled with anger, he confronted General, leader of Repliforce, defeating him in battle. Upon the end of the fight, General realized that someone had taken control of Final Weapon, aiming it at Earth. Zero rushed to the Final Weapon control center, only to find Sigma waiting for him. Sigma reveals part of Zero's past at a time when Sigma was still the leader of the Maverick Hunters.

During this vision, Sigma and the Maverick Hunters are called to an abandoned laboratory to fight a Maverick of immense power. Sigma enters the building and the Maverick is revealed to be a maniacal Zero, with no power other than sheer brute strength and rage. Zero manages to overpower and grievously injure Sigma, but before he can deal a finishing blow, the light in the center of his forehead flashes on, revealing a "W" and causing Zero to collapse in pain. Sigma gathers his remaining strength and punches Zero in that light, rendering him unconscious. Sigma leaves, asking the Reploids outside to have the Maverick delivered to Dr. Cain for analysis. It is believed that during this fight that both Zero and Sigma were infected with the Maverick Virus, which later caused Sigma to betray the Maverick Hunters, however it corrected the flaw in Zero's programming, allowing him to awaken and later join the Maverick Hunters.

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, 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.

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 respond to X's request, although he seemingly realized X's seriousness about the topic and the eventual battle between him and his best friend.

Mega Man X5


The space colony "Eurasia" was set to impact Earth, recently being coated in a large outbreak 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 the bigger threat. In order to stop Eurasia's impact, X and Zero both would gather several enhancement parts to power up an old energy cannon, known as "Enigma", to destroy the colony before it could devastate the planet. While doing so, Zero noticed his strange reaction towards the Sigma Virus. While others (including X) got hurt by being surrounded by the virus, he himself actually felt energy growing inside himself; multiple infections of Sigma Virus anomalies even turned him invincible for a brief period of 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, 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 directed right into the colony to have it self-destruct right at the core. The shuttle would be operated by Zero, who volunteered because he felt that the world needed X more than himself. The operation succeeded, and Zero survived; 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 the 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 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 he still didn't show any Maverick behavior. Not wanting Zero to become a Maverick, X would fight his friend in order to have him brought back to Hunter Base. Eventually, the battle would end in a draw (with X using Soul Body on Zero and getting injured by him while using it). Upon seeing X and Zero both 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, seriously damaging him. The remains of Sigma attacked Zero and X one final time, impaling both of them through 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 cease to function. After recalling his 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 Dr. Light, X searched for Zero, finding 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 unsuccessful, 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, Sigma revealed himself and prepared to destroy X. Zero, however, regained consciousness and he jumped into the line of fire, protecting X with his body, only to get mortally wounded in the process. When X destroyed Sigma in this scenario and was damaged badly, Dr. Light would appear to save him; however, Light erased X's memories of Zero and would implant a protection inside X's mind so no information about Zero would be accepted.

Originally, X5 was supposed to be the final game of the series and Zero getting killed would make way for the Zero series. However, X6 was produced unbeknownst to Inafune 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
Set a few weeks after the Eurasia incident, Reploid scientist Gate found a piece of Zero's body near the crash site. Using the information he gathered about the Sigma Virus and Zero's DNA, Gate has seemingly gone mad, creating 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. 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.

Zero's ending in this game helps to mend 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 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 artbook 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 two 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
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 seems to have some resentment towards the workload, as indicated when he says, "I can't believe I'm back here again!" in an irritated tone in his introduction, which could also imply that he's back in the same setting as the Opening Stage of Mega Man X). 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. While fighting alongside Axl, Zero learns from him at least some of the details about Red Alert's downfall. 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). 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 melee weapons to replace his saber. This tradition would continue through the rest of the Mega Man X series and up to the Mega Man Zero series.

Mega Man X8
Zero continues to work with X and Axl, now an official Maverick Hunter, in dealing with new threats. One of the new navigators, a purple-haired girl named Layer, has shown a romantic interest in him; Zero has not returned her feelings however, simply keeping the relationship professional. Zero's memories of the virus incident from 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 first X game (presumably it happened when Sigma shattered Zero's head gem as depicted in X4, though the unlockable animation The Day of Σ in the PSP remake has put a few doubts on this). This information was long-since stated in Japanese sourcebooks, as well as implied as early as X4, but was never before made officially available to the public in other regions.

Mega Man X: Command Mission
In the game, 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 was presumed dead, until he reappears some time later and attacks one of the rebelling Reploids in a mechaniloid factory. At this point, Zero joins 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 as well 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). Zero briefly hesitated when his allies attempted to stop Redips from using the Supra Force metal, presumably out of shock that Spider and Redips were the same and thus he was "badly duped." However, he would recover and, with the others, defeat Great Redips in the end, before returning to Earth in a broken off part of the elevator.

Mega Man Zero and Mega Man ZX series


At some unknown point, Zero realized that he carried the virus inside him and may even be continuing to 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. At the same time, a project was started to analyze Zero as it had been revealed previously (during the Eurasia crisis to be exact), that Zero actually reacted positively to the Sigma Virus, and 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, and they were researched by different scientists. Zero's body would be used by Dr. Weil to create Omega and start the Elf Wars, and Zero's mind was given a new body to assist X in the war. After the war had ended, Zero decided to seal himself away again, later being awakened by Ciel to assist the Resistance against Neo Arcadia in the Mega Man Zero series.

Many years after the end of the Mega Man Zero series, Zero would return in the Mega Man ZX series as Biometal Model Z, which contains the "soul" of Zero. Although Biometal Model Z is not usable by itself, it can be combined with Biometal Model X to form Model ZX, the title Mega Man. Zero himself also appears in a flashback scene from Vent's story in Mega Man ZX.

Tatsunoko vs. Capcom: Ultimate All-Stars
This is the third fighting game with Zero as a playable character, but this is the first time in years to feature Zero in his X series form since Maverick Hunter X in 2005. Zero can use many of his command arts including Ryuenjin, Hienkyaku, Shippuuga, Sentsuizan, Kuuenzan, Twin Dream (Sougenmu), Rekkoha, Hadangeki and Dark Hold. In a nod to the following series, his powered-up Z-Saber takes its triangular Mega Man Zero shape when he uses Dark Hold.
 * In Zero's ending, Yami springs back to life after being defeated and attacks Zero, knocking him out. Dr. Wily then appears in Zero's mind and tells him not to give up on the task he gave him.
 * He also makes a brief cameo in PTX-40A's ending as one of the robots in the tournament.
 * Ryoutarou Okiayu reprises his role as Zero's seiyuu.

Marvel vs. Capcom 3: Fate of Two Worlds
Zero is a playable character, appearing once more in his Mega Man X series appearance, with his battle music from X2 as his theme music. Zero appears similar to his Tatsunoko vs. Capcom appearance, but with a few modifications: he has most techniques that he had in TvC, plus new moves like Raikousen from Mega Man X8 and a powerful wave slash attack known as Genmu Zero, which is his final attack as a boss in X5. Other than that, not much else has changed other than his normal attacks undergoing some minor tweaks and many of his combos working differently than in TvC. In Japanese, Ryoutarou Okiayu is still Zero's seiyuu, but in English, he has a new voice actor, Johnny Yong Bosch.


 * His fighting stances in the Capcom vs. games are inspired by his X series' stances (even though they look very different from each other), with his TvC stance having Zero's both fists clenched (X4-5 stance), and his MvC stance with the leading hand open (X6 stance). His standing light, medium and heavy attack in both games are based on his basic attack combo, his crouching medium based off of his crouching attack, and his jumping medium is his normal midair slash. However, all animations look different because the Z-Saber is holstered on the leading shoulder in his stance, rather than the following shoulder like in the X series' sprites (and in canon via the artworks, also being sheathed over his left shoulder).


 * Zero's alternate colors all resemble other characters from the series: The blue one is based on X, the black one having a resemblance to his older brother Bass than to his actual black armor, and the purplish one resembling Axl more than his Zero series counterpart.
 * In Ultimate Marvel vs. Capcom 3, he gains three new colors, one for his Mega Man Zero version, another based on Vile and the last based on X's first armor from X1. His X scheme, however, is removed in this version, since he gets a downloadable X alternate skin.


 * One of Zero's new winquotes snidely mentions X (more specifically, his win quote against Hawkeye: "You're very cunning. You have that in common with X. You also lost to me, so you share that too."), which some see as a response to many fans' negative response of his absence in the game. Ironically, X himself is his DLC costume in Ultimate.
 * In his ending, he is assisted by Silver Surfer in returning to his world, but winds up in the Neo Arcadian era instead. Silver Surfer informs him that this time and world already have a Zero, but goes by the name of "Mega Man Zero", expressing his confusion over this. In Ultimate Marvel vs. Capcom 3, the ending has an additional line of dialogue. After Zero claims he is not Mega Man Zero, he further adds that "if there ever was such a being" in his bewilderment. This is only semi-ironic in that the other Zero is in fact his future self (not that Zero himself would know about it). The Surfer's bewilderment may be a nod to early confusion in the fandom about Zero being considered a "Mega Man" or not, what with the title of his own series.
 * He also appears in Nova's ending as part of the new Mega Nova Corps alongside Mega Man, Roll, Proto Man and Beat.

Project X Zone
Zero (in his X series appearance) appears alongside X. He, along with X and Vile, first appears in the game during Chapter 20, and is once more voiced by Ryoutarou Okiayu.

Early on during Chapter 29, Zero expresses shock upon noticing Iris, who appears alive and well. After hearing that she still wishes to live in a Reploid only world together with Zero, the latter reminds her that such a world is nothing more than an imagination. However, Iris then asks him if such a world is meant to be his purpose and desire, which is partly why Iris appeared. Zero then suffers an emotional breakdown, questioning himself about whether or not a Reploid only world was what exactly he was fighting for. He then gets taunted by Vile in the process for getting emotional over a girl's wish, claiming that the former is exactly the same as the latter before. Zero becomes paralyzed with anguish and is unable to move.

Confused about Iris at first, the other characters present then realize that Zero is in trouble, and that they and X must protect him from danger, while attempting to defeat Vile at the same time. The game splits the winning conditions down to two options: reach Zero by the end of the ninth turn or defeat Vile, otherwise a game over will be declared. Until then, X's unit is paralyzed and unable to fight.

After any of the other party members reach Zero and heal him, he eventually recovers from his emotional breakdown and recalls his duty as a Maverick Hunter, and tells Iris that a Reploid only world is impossible. Aura from .hack appears and states that Iris and her feelings are not supposed to be present, hence causing her to fade away. Before she vanishes however, she gently suggests to Zero that things between them are okay, and encourages him to never give up before bidding him farewell. His resolve restored, Zero confidently declares he will rejoin her someday.

He uses Rakuhouha alongside X's Nova Strike (while the latter dons the Ultimate Armor) during their special attack, and uses Genmurei alongside X's Hadoken during their multi attack. The latter is learned right after Zero is rescued.

Other techniques that Zero uses in this game include Kuuenzan, Ryuenjin, Hyouretsuzan, Raijingeki, and Shippuuga.

Marvel vs. Capcom: Infinite
Zero appears as a playable character alongside X, marking the first time the duo to be playable in the same crossover fighting game. In the story mode, it is shown that his routine core is being altered by Grandmaster Meio from the Strider series via Power Stone, looking somewhat similar to his Maverick form, until X and Rocket Raccoon rescues Zero by beating him. X and the others than gather the Power Stone.

Aside from property-changes on his moves' effects, a new ability of Zero's is instead of being able to cancel into his Hyper Zero Blaster firing animation from any of his special moves (from Ultimate Marvel vs. Capcom 3), is being able to release a maxed-out charge of the said blaster during any of his specific moves to pave way for new followups (Hadangeki into Rakuhouha, Ryuuenjin into Hyouretsuzan, Sentsuizan into Hisuishou and Raikousen into Mikazukizan). Another new move to his arsenal is the Raijinshou as one of his new Hyper Combos. His Premium Costume is an original creation called "Special Zero" that gives him a more more detailed mecha appearance, patterned after X's Truforce figurine design.

Super Smash Bros. for Nintendo 3DS and Wii U
Zero appears as a collectible trophy in Super Smash Bros. for Wii U. In addition, both versions contain a downloadable costume for the Mii Swordfighter that portrays them as Zero, and their sword is also portrayed as the Z-Saber while wearing this costume.

Super Smash Bros. Ultimate
Zero appears as an Assist Trophy in Super Smash Bros. Ultimate. Zero also appears as part of the Spirits found in the game in both his X series and Zero series incarnations as Primary-based Attack Spirits.

Zero's spirit from the Mega Man X series is one of the spirits that can be upgraded when its level is raised high enough. Its original version known as Zero Buster is based around his original design from Mega Man X, but can be upgraded to Z-Saber changing the artwork based around the updated design which was first introduced in Mega Man X2 (though the artwork used is from Mega Man X5)

In addition to stat-based power-ups from both Spirits, the Z-Saber version allows for enhanced movement speed and weapon attacks as its special ability, while the special ability for the Mega Man Zero version increases damage for all sword-based attacks.

On September 4, 2019, the Zero costume for the Mii Swordfighter became available again as DLC.

TEPPEN
Zero is a playable character in TEPPEN, a Purple type Hero that was included in the 2020 expansion Haunted by Memories. He also appears in several cards.

Zero is a SA-Class Hunter that despised evil and had no memory of his origin. Like X, Zero is an ancient robot that felt in a deep slumber and awakened many years later. Shortly after awakening, he faced Akuma and their battle destroyed the building where Zero had awakened. After seeing a large fire in a nearby city, Zero went to its direction and stopped the responsible, a Rathalos. A mysterious woman forced Zero to remember his past, causing him to go out of control and fight X. He returned to normal before finishing X, and is shaken by what happened with him, believing that he may be a Maverick like the ones he fought in the past. Not remembering his past and not knowing what to do, Zero decides to accompany X in his journey to the Land of Illusion to learn the truth.

Other appearances

 * Zero appeared in Street Fighter x All Capcom.
 * Zero appeared as an event character in Zombie Cafe.
 * Zero appeared as an event character in Dragon Coins.
 * Zero appeared as an event character in Bouken Dig Dig 2.
 * Zero appeared as an event character in Dragon Poker.
 * Zero appeared as an event character in Elemental Story.

Cameo appearances

 * Zero can be seen in the background of the Running Battle mode from Super Gem Fighter: Mini Mix.


 * Zero has a card in all games from the SNK vs. Capcom: Card Fighters series.


 * In Mega Man Legends and Mega Man Legends 2, an item called Zetsabre can be found, which can be used to produce the Blade Arm. Zetsabre is a mistranslation of Zero's Z-Saber.


 * A poster of Zero, in his "Black Armor", can be seen in the general store of Yosyonke City in the game Mega Man Legends 2, where he is described as some sort of comic book hero. Upon closer inspection, the image of Zero himself seems to have been taken from Mega Man X4, specifically, the "Weapon Get" screen.


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


 * Zero appears in Rockman Xover as Battle Memory and as one of the heroes that OVER-1 has to rescue, being rescued in World 2.


 * An actual NetNavi bearing the name Zero.EXE appears in the game Mega Man Network Transmission, and the anime Rockman.EXE Beast+, one of the few characters from the X series to receive a NetNavi counterpart. Here, he appears 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 the anime. 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 lives.
 * Two Battle Chip artworks feature Zero. The Z-Saber chip displays Zero.EXE, and another, the Z-Saver, shows the Mega Man Zero version.

Rockman X (manga)
Early in his days as a Maverick Hunter, Zero and Storm Eagle were rivals that eventually became friends and partners. After Storm Eagle's girlfriend, Teal, died while assisting Zero in a mission, Storm Eagle asked to be transfered and Zero didn't saw him again until Sigma's rebellion. To deal with Sting Chameleon and his minions, Zero planned to burn down the forest, but as X didn't agree with it, he gave X time to solve the problem, being successful. Zero is later captured by Vile and sacrifices himself to destroy Vile's Ride Armor.

In Rockman X2, Dr. Cain found Zero's body and tries to repair him, but the X-Hunters stole him, giving him an improved body and installing a chip that turns him into a Maverick. X destroys the chip, changing him back to normal, and they defeat Sigma.

In Rockman X3, he faces Blast Hornet. After X and Zero defeat the eight Mavericks, they are defeated and captured by the Nightmare Police, and are set to be executed on December 25. While they are rescued by Marty and Dr. Cain, Zero is apparently killed by Dr. Doppler, but is shown to have survived and helps X by giving him his saber.

Zero is repaired by Dr. Cain and continues his work as a Maverick Hunter, joining the Repliforce in a mission and befriending Colonel. After X's return, Zero participated in the party celebrating his return and saw Eregion's attack.

Irregular Hunter Rockman X
The manga starts with Zero, X, and Vile working together to take down a Maverick. After the mission, Sigma thinks that Zero may cause trouble to his plans, and decides to label him a Maverick, having Maverick Hunters pursuing him. Not believing that Zero became a Maverick, X covers Zero for a while so he can prove that he is not a Maverick. However, after some time, Sigma orders X to destroy Zero. While X goes after Zero and tells him what he was ordered to do, Zero attacks X, but X does nothing as he does not wish to harm his friend. Seeing that X isn't an enemy, Zero tells that during his investigation he discovered that Sigma is planning to conquer the world, and convinces X to join him to stop Sigma. Vile appears with three Maverick Hunters and reveals that he was waiting for them to destroy each other to finish the survivor. Zero and X defeat the three Hunters, and Vile retreats. Watching the battle, Sigma decides to start his plans and attacks the city, but Zero and X manage to stop the attack, forcing Sigma and Vile to escape.

Rockman X The Novel: Irregulars Report
Zero appears with a role similar to the games.

Power and abilities
Zero is a very adept combatant on the battlefield. Originally, his power far exceeded X's (until X himself grew in power). His power as a robot from a past age is considerably exceptional in the Maverick Wars. In Mega Man X, Zero was equipped with a powerful buster weapon known as the Zero Buster, but from X2 and onward, Zero wields a melee weapon known as the Z-Saber, a sword with a blade composed of pure destructive energy, modeled after the lightsaber of Star Wars fame. It is for this reason that Zero is often used for seasoned players as he is required to fight up close rather than at a distance. His first playable appearance in Mega Man X3 is more or less essentially a future representation of how X will turn out, unleashing double charged shots and the almighty Z-Saber which fells bosses with a few mere swipes.

Unlike his comrades, Zero does not copy the powers/weapons of defeated Mavericks, but instead, his Learning allows him to acquire special attacks known as Techniques (必殺技) in the X series and as EX Skills in the Zero series, which are attacks based on techniques utilized by bosses. He does not require the use of a buster weapon as the attacks often utilize his hands or enhances his Z-Saber power by empowering the blade with elemental properties. The Zero Buster can be utilized from both arms, as evidenced by some gameplay and cutscene representations interchangeably showing the buster arm as being his left or right.

Unlike X, Zero cannot obtain performance-enhancing armors, with a few exceptions. This is due to the fact that during the time Zero was created, Dr. Wily could not prepare any future armor enhancing upgrades for him like Light had done for X, thus Zero's durability stayed consistent, making him a traditional Glass Cannon. Defined in SNK vs. Capcom: SVC Chaos, Tatsunoko vs. Capcom, and Marvel vs. Capcom 3 (more so in terms of his bio), Zero appears to not be so overly strong (unless he wasn't infected first with the Sigma Virus when he was first found, as he was uncontrollable or in his Awakened Boss fight in X5) as his Marvel vs Capcom 3 power grid statistics gives his Stamina rating a 3/7, but his other stats (Strength, Speed, Intelligence and Energy Projection) a 5/7, with his Fighting Ability as a 7/7. This shows that what Zero lacks in raw strength with the absence of the virus he makes up for extreme fighting ability and skills in many other fields, enabling to out-duel/wear down nearly any foe, along with showing extreme adaptation to much of his battles (which also plays in hand with his versatile move list as of late). This is expressed in the aforementioned fighting games where Zero has low health and average attack, though many claim him to have some (if not many) of the best and longest combos (even loops or near/true infinites) out of all characters.

In Ultimate Marvel vs. Capcom 3, Zero (like several characters from the original version to the revision), has had his power grid changed. His Stamina and Strength are now 2/7, his Intelligence a 3/7, and all the rest of his other stats are now 5/7. This shows that not only Zero puts more than just skill into his fighting ability, and that he uses all his speed and knowledge to back up his fighting prowess. His "Learned" intelligence also shows Zero tends to clear his mind during fights for better focus, and his 5/7 fighting ability while brought down to a reasonable level shows that while Zero only knows a single form of combat, he is no doubt a pure master of it.

The original X games, however, have Zero's Z-Saber be capable of destroying several normal enemies in a few blows. The fighting games seem to decrease it to give more balance, and coincidentally give a possible accurate description of Zero's statistics. Zero may also be aware of his low durability (in comparison to his comrades), and may also have enough skill to last in a fight to fight/parry off any hit that comes to him, describing more of his skill as a Master Swordsman. This makes him a rather unique Glass Cannon as he not only he's weak on defense and strong on offense like the other kinds in fiction, but Zero has skills in several other fields of battle with great ability to adapt to practically any opponent he fights; Glass Cannons usually have raw power, which Zero seems to lack often, putting him in the category of a "Gradual Grinder". And like the "Fragile Speedster" archetype of characters, Zero has also focused very well on speed.

Zero's long combos in fighting games seems to nod at his personality as well, taking note that he shows no mercy to his enemies as he basically never holds back on them, showing he always fights to the best of his ability. This shows that Zero is somewhat more powerful than he lets on in-universe.

Marvel vs. Capcom 3 profile

 * Real Name:
 * Zero


 * Occupation:
 * Maverick Hunter


 * Abilities:
 * Has great physical ability as well as excellent skills with a variety of weapons. He is able to learn the abilities of the enemies he defeats and add them to his existing arsenal, making him even stronger than before.


 * Weapons:
 * His primary weapons are the Z-Saber, an energy sword, and his Zero Buster, a weapon capable of firing energy shots.


 * Profile:
 * Ever since being found in a cave by Sigma, he has worked tirelessly as a Maverick Hunter. Beneath his cool exterior lies an extreme intolerance for evil; once he gets into a fight with a Maverick, he won't stop until his enemy has been mercilessly cut down. He is best friends with X of the Maverick Hunters' 17th Elite Unit.


 * First Appearance:
 * Mega Man X (1993)

Notes:
 * Capcom characters in Marvel vs. Capcom 3 don't follow the standards of Marvel's Power Grid. Zero's power grid statistics also change in Ultimate Marvel vs. Capcom 3. (Strength and Stamina becomes 2/7, Intelligence becomes 3/7, and all other stats become 5/7). It should be kept in mind, that the crossover are non-canon and the Power Grid ratings are mere interpretations of the developers.
 * The bio states that Sigma discovered Zero in a cave, which is incorrect as he was found in a desolate laboratory by Gamma's unit, which met an unfortunate demise upon awakening him. Sigma however only fought Zero, and barely made it out alive at a terrible cost.

Merchandise
Zero had several toys and figures released by Bandai. Among them were the Mega Armor models with interchangeable armor:


 * Zero - A normal model of Zero with his armor from X3 and up. Features his Z-Buster and Z-Saber.
 * Plated Zero - A plated version of his normal model.
 * Transparent Zero - A clear version of his normal model.
 * Irregular Hunter Zero - Zero with his black armor. Features his Z-Buster and Z-Saber.
 * EX Armor Zero - Zero with the X Armor from Rockman X Mega Mission 3.

And the D-Arts figures. Zero also had figures done by Furuta, Jazwares, and Kotobukiya, and has a Nendoroid figure.

Trivia

 * According to Keiji Inafune, he envisioned Zero as the new "Mega Man" and wanted him to be a playable character from the start. Keiji wanted to introduce something new and different to the franchise, but understanding that it would not be wise to completely go against everything that had already been established (also fearing that Zero's drastic appearance would receive a critical reaction), he did not mention this idea to his superior and submitted Zero as the sub character to Hayato Kaji's "Mega Man" (X) as originally intended.
 * Some say that Zero's final design was inspired by Proto Man, which seems likely due to similarities in color and other similar details. Coincidentally, both have also been voiced by Ryoutarou Okiayu in Japanese, though only Zero has been consistently voiced by him via his X series appearances and crossovers.
 * Also coincidentally, the serial number for Proto Man is formed only by zeros (DLN-000)
 * This theory has been confirmed in an internal design document shown on the Rockman Unite event for the series 30th anniversary that took place in Hirakata and Hanayashiki Parks.
 * In X4, Zero was actually going to have his own Ultimate Armor, known as "Mega Armor", instead of his Black Zero recolor. This indirectly explains why the Black Zero is just a simple aesthetic change before becoming an actual upgrade in later games. (The special code for X's Ultimate Armor gives him a slight recolor, and finding a Light Capsule gives him the armor. Presumably, this would also the case with Zero if he actually had an Ultimate Armor.)
 * As revealed in Mega Man 11, in his youth Dr. Wily believed that if he granted robots "unstoppable power and insurmountable speed" that could outdo humans, he would cause humanity to celebrate robots for what they were as opposed to considering them as mere tools, as that kind of power could turn any robot into a "hero". This is ironic, as Dr. Wily had created Zero, his final creation, as the most powerful and destructive to exist, but Zero ultimately ended up becoming a formidable force of good.
 * Although Zero and X aren't technically Reploids (robots based on X's schematics, "replicated androids"), as they are original androids from the past (technically making them "Robot Masters"), they are known as such because the term Reploid is used for all androids with human-like A.I, and for reasons of simplicity.


 * In his foreshadowing appearance in Mega Man 2: The Power Fighters, Zero's silhouette is shown with his upgraded frame as of Mega Man X2 instead of his default frame, as seen with the shape of his shoulder (styled akin to his shoulder guards). Though this was due to the upgraded frame being unusable at the time as Zero was still unruly before being sealed away.
 * In X1-X4, Zero's eyes are green in-game (even though his eyes were brown in his mugshot from X1) and blue in artworks. His eyes are completely changed to blue in X5 onward. His eyes are also green in Maverick Hunter X and Tatsunoko vs. Capcom. In the Zero series, his eye colors range from black to purple.
 * Zero has been depicted with a full head of hair in manga form, but never in the video games. In the Rockman X manga, Zero's helmet is constantly removed, either by himself or due to the helmet being damaged in battle. He is shown to primarily keep his hair slicked back, although it appears more unkempt following larger battles. In the Rockman Zero manga, Zero's helmet is used as a signal to display his split personality syndrome; the cowardly inept personality appears without a helmet, and features loose unkempt hair, while his stoic combat-ready personality appears wearing the helmet. This later is the real personality of Zero.


 * In X5, if the player looks carefully at the intro sequence, where there are green words scrolling down the screen, one of the words say "Wily".
 * In the X series, Zero is a Maverick Hunter fighting against insurgence and rebellions caused by Mavericks. In the Zero series, Zero joins the rebellion against the current government, in the process becoming labeled a Maverick himself.
 * Of all the characters to have appeared in the series, Zero is unique in that his Japanese voice actors differ in the series he appears in. In the X series, his voice actor is Ryōtarō Okiayu, while in the Zero series, his voice actor is Yuuto Kazama.
 * This change of voice could be on the fact that Zero's mind is transferred to a copy of his body that features a different voice chip.
 * It's rather interesting how Zero, a creation of Dr. Wily, actually ended up fulfilling  Dr. Light' s dream instead of Wily's - in conclusion of a lifetime fighting against hordes of Reploids based on Light's creation, no less, whose leaders and/or master manipulators often carried even darker ambitions than Wily.
 * Also interesting is how despite not being intended to be Three Laws compliant, at the end of Zero 4 where Zero fights Weil, Zero unwittingly follows the fittingly named "Zeroth law", which was made to prevent robots from harming a human, unless said harm would benefit humanity in general.
 * As Model Z, Zero is the only Biometal to actually attack when not MegaMerged, paralyzing opponents while not even wasting a drop of his energy.
 * Having been completed by Dr. Wily between the Classic and X series, Zero is the longest-lived robot in the Robot Continuity, with an (ultimate) age of termination of 300+: 100+ for the time between the Classic and X series, 200+ more for the Maverick and Elf wars, another 100+ for the inactive hibernation state in which he begins the Zero series, and three for the Zero series until Zero 3, where his original body was ultimately destroyed.


 * In Ultimate Marvel vs. Capcom 3, Hawkeye refers to Zero as an "Angry space midget with a sword." Zero's win quotes mentions X as cunning, but also shares that X also lost to him. With Frank West, he calls him a civilian, and his win quotes when defeating Frank West refer to his camera as a "photo capture device". Zero likely refers to it in this technical sense because cameras in the future obviously look much different than the one Frank uses.
 * In both versions of Marvel vs. Capcom 3, Zero will say, "Another soulless copy." when facing himself in a mirror match. This is a possible reference to both X2 and X6.
 * In Megaman X Command Mission game, Zero is always seen as left handed with his saber in cutscenes but in battle, he uses his right hand.
 * The theme when Zero is discovered in X6 is a remastering of "Variable X" from the first X game.
 * In both versions of Marvel vs. Capcom 3, when Zero uses his Genmu Zero attack, if one sees Zero carefully, he will be emitting an aura similar to his Maverick state in X5 when he executes the attack.
 * Compared to other characters, Zero probably has the most love interests:
 * In X4, Iris has feelings for him.
 * In X8, Zero's Navigator, Layer, shows signs that she has a crush on him.
 * In the Zero series, Ciel has feelings for him.
 * Despite the many love interests, it's never been officially stated that Zero had romantic feelings for them in return, although he seemed to regard Iris with the most emotion.
 * Zero appeared in an episode of the Screwattack web-series Death Battle, where he fought against Dr. Eggman's creation of Metal Sonic in Metal Sonic VS Zero. In the end, Zero won due to his superior durability, strength, comparable speed, and weapon variety, as well as Metal Sonic simply not having the means to put down Zero for good.
 * Also, both Dr. Eggman and Dr. Wily appeared in a previous episode, their battle was outmatched by Metal Hazard, so the fans say Zero vs Metal Sonic is a spiritual sequel. And both Zero an Metal Sonic are related to each other, in one thing, is that both were created to outpower the doctors nemesis (Mega Man and Sonic the Hedgehog, respectively).