Zero (Mega Man Zero series)

"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!"

- Zero

Zero (ゼロ) is the titular main protagonist of the Mega Man Zero series. After the Mega Man X series, Zero offered to have himself sealed for research, his mind and body being split and given to different research teams. During the Elf Wars, his body was used to create Omega, and his mind was transferred to a new body to assist in the war, remaining in that body for the rest of his life.

Appearance
Zero still sports a red color scheme, although slightly brighter than his previous body, and retains his long blond hair. Besides those key features, Zero was given a design overhaul between the Mega Man X and Mega Man Zero series. His armor is lighter and more humanoid, and he's given a more streamlined helmet, with a sharp blue crystal at the front, to present a much sleeker look. Unlike his previous form, Zero's arms cannot change into a buster form and instead keeps his weapons holstered around his body.

Personality
Given that he's been in stasis and lost his memory, Zero is ignorant of some matters and confused about others, sometimes to the point he starts doubting or believing that he can't win. This is seen a couple of times. First when Ciel was captured by a Golem and Zero was battling with the Buster Shot, which was not doing too much damage. He was slowly starting to lose hope until X gave him his Z-Saber back. Another example was when Dr. Weil told him he was a copy, causing him to believe he was not the real Zero. He only gained his confidence back when X claimed he was indeed Zero in spirit, swapping roles so that X is the one that encourages Zero to fight instead of the other way around as it used to be during the X series.

Probably due to his amnesia, Zero became a much quieter and distant character, especially in the first game. He rarely prolongs a conversation and provides only quick answers. He keeps his expression serious throughout the series, rarely showing any other kind of emotion, now no longer smiling at all.

His moral code also seems to have changed between the series. Although he was a heroic and proud Maverick Hunter in the X series, he became a soldier who will do whatever it takes to accomplish his missions in the Zero series. This includes questionable methods, from sacrificing the lives of Cyber-elves to gaining more advantages in missions, killing brainwashed soldiers and killing the Baby Elves without seeking an alternative solution. Although the first two are completely optional, the third isn't, though he did it in self-defense. He claims that he no longer cares about being considered a "hero", and that he just fights to protect what he cares about.

He goes far enough to not restrain himself from the possibility of killing a human, a taboo that any other protagonist of the franchise wouldn't have the courage to break (though that being said, the circumstances involved left him with no other choice as Ragnarok would have destroyed Area Zero otherwise). This act properly classifies him as an anti-hero, with Zero himself admitting in the fourth game that he has never seen himself as a hero, although it's unknown if this was his thinking in the X series or if it's the consequences of his amnesia and new experience in the Zero series.

There was one thing that Zero seems to have maintained; his respect and admiration for his old partner, X. After defeating Copy X in the first game, he noted that despite his memory loss, he remembered the original X as being a true hero (and in the Ciel's Memory radio drama, even explained how X originally was a coward and prone to worrying too much, and that his ultimately overcoming these bits was what made him a hero).

The Elf Wars
At some unknown point, Zero realized that he carried a virus inside him and may even be continuing to spread it all over the world during his missions as a Maverick 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, 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 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 also worked in the lab, planned a different way of dealing with the Mavericks, as he was unsatisfied with the result. Weil started a 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".

Thinking that it wasn't enough to simply cure the Reploids from the virus while they still posed a threat to society due to their free will, Weil decided to create his own, radical solution, while making himself ruler of the world in the process. Project Elpis was the end result: to create a Reploid who would become the perfect ruler, by using the power of the Mother Elf to control all the Reploids in the world, thus preventing them becoming Mavericks in the first place.

However, since the world was at peace at the moment thanks to the Mother Elf, he needed to give the government a reason to sanction Project Elpis. He secretly stole the Mother Elf and reprogrammed her into the Dark Elf, whose purpose was to create Maverick outbreaks by brainwashing Reploids. Baby Elves, small copies of the Dark Elf, were mass-produced to cause violent Maverick outbreaks worldwide.

As new Mavericks arose and caused terror and destruction in scales never seen before, the government heeded Dr. Weil's pleas and sanctioned Project Elpis to bring this new and devastating conflict to an end. For the project he was given Zero's body, which possessed the necessary virus countermeasures for creating the perfect ruler, Omega, the messiah of Dr. Weil.

For Omega to control all Reploids worldwide with the Mother Elf, a massive armor was constructed around Omega for the Mother Elf to fuse with it. In addition the armor also boosted Zero's body to its absolute limits and granted it the ability to regenerate any damage. Along with the armor, Omega received new weapons, suitable for his new size and weight. Unknown to everyone Omega received a new personality, which was absolutely loyal to Dr. Weil's orders. With Omega completed by fusing it with the Dark Elf, the baby elves would be redundant as they were no longer needed.

In the fourth (and what would be the last) year of the war, Zero, in possession of a new body created for him, would wake up so he could fight alongside X against the new threat. At some point during the conflict, which were now known as the Elf Wars, Zero reclaimed the Dark Elf from the mavericks and used her to bring the uprisings to a end.

It was then where Weil revealed his true colors and ordered Omega and a group of Mechaniloids, similar to Neo Arcadia's later Golem models, to attack his former allies. However, because Zero reclaimed the Dark Elf in time, Omega was unable to fuse with the Dark Elf. He was defeated after a hard battle by X and Zero using the Final Strike.

After the war had ended, Zero decided to seal himself away again, this time, forever. Though X tried desperately to stop his friend, the sealing process had already begun when X arrived, and could not be stopped. Before he lost consciousness, 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 humankind, just as X believed in them. With these final words, Zero's seal was complete.

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

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

Mega Man Zero 2
One year later, Zero is still traversing the harsh desert, and still hunted by Neo Arcadia. After another battle with the Neo Arcadian Forces, Zero finally succumbs to his injuries and exhaustion, and collapses. When he wakes up, he is now in the New Resistance Base, brought there by unknown means (later revealed to be Sage Harpuia's doing), and meets the new members, including a new commander, Elpizo.

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

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

Mega Man Zero 3
During the two-month gap between the third and second game, there has apparently been a truce between Neo Arcadia and the Resistance. Ciel, having finished her energy research by creating the "Ciel System", submitted a sample of her work to Neo Arcadia, hoping to open up the chance for peace talks. In the meantime, Zero and Ciel lead a small group through a snowy mountain, as while they were trying to locate the Dark Elf (presumably to end her curse), they found another energy signature resembling the Dark Elf located there. Upon arrival at the origin of the signal, they discover an immense ship. The Neo Arcadians had roped off the ship, so Zero decides to get a closer look by sneaking in. However, upon arrival, Ciel and the rest of the group was discovered by the Neo Arcadians. they didn't seem to be harmed though, thus confusing Zero. Harpuia then appears and says that he's letting them off the hook, as there's "bigger fish to fry". After Harpuia leaves, and Zero tries to figure out who the Dark Elf is and why she seemed familiar, Zero then hears a monstrous voice calling him. Upon arriving at the interior of the ship, Zero discovers that Fefnir and Leviathan, as well as their entire unit, was soundly defeated by an immense figure: Omega, the Devil Reploid. Zero then realizes that Omega was the one who called him, and they fight. Zero seems to defeat Omega and cause grievous damage, but then Omega started regenerating the wound. Harpuia then cuts in and is about to deliver the coup de grace when a mysterious man, Dr. Weil, tells Omega that he is to serve Harpuia as an ally. Copy X MK II then appears and announces that he revoked Dr. Weil's exile. Weil, Copy X, Harpuia, and Omega then depart after some discussion, although not before Weil cryptically remarks that he's interested in how well Zero will do "in that body of his."

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

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

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

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

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

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 Variants (soldiers which had replaced the Pantheons) that attacked a refugee truck Caravan. After countering the attack, Zero and Ciel met Neige, a human journalist who tried everything possible to both bring all people safely to their new refuge, Area Zero, and to find out the whole truth about Weil.

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

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

All is not well, however. A second laser fired from Ragnarok alerted everyone that it was still operational, and that the station is now falling down to Earth. After going through Ragnarok's defenses to reach the core, Zero discovers Weil waiting for him. Having actually survived Ragnarok's laser fire, Weil teleported into the space station after the blast, maneuvering it to crash into Area Zero. After the first of their two battles, the space station is damaged. Ciel pleads for Zero to return to Earth, lest he get stranded due to increasing transporter interference. Seeing Weil is still alive, however, Zero passes the offer to go back and proceeds to finish him off once and for all in their second battle, ultimately sacrificing himself as the destruction of Weil's last form causes the station to explode.

Zero's sacrifice opens the eyes of many, finally bringing peace between the Reploids and humans left on Earth. The aftermath, however, leaves his friends grieving at his apparent death (his actual fate remains uncertain), especially Ciel, who is later inspired to continue her work to create harmony between Reploids and humans.

Mega Man ZX
Zero returns 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.

After defeating Prometheus, 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").

Omega also appears as an optional boss in Area N-1. Defeating him in Normal or Hard will grant access to a mysterious artifact which allows the player to use Model OX.

Mega Man ZX Advent
Model Z, alongside Model X, reappear in this game and are still in Vent/Aile's possession, and Model ZX can be copied by Model A. After Ouroboros 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 against Master Albert. 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 completes hard mode, then a secret ending shows the four enemy Mega Men alive and well, in their Mega Man forms. As of then, Model Z's whereabouts are unknown, mirroring Mega Man Zero 4. He is implied alive, as he said before he disappeared "It's not the day to meet my maker," referencing that no matter what, even in death, he continues to live, resurrected in some way or another, always fighting with whoever he is with.

An interesting point in this is the fact that he disappeared aboard Ouroboros, made from Model Ws, which are made from pieces of the Ragnarok, the same space station where Zero apparently died in Mega Man Zero 4.

SNK vs. Capcom: SVC Chaos
Zero appears as a hidden playable character and serves as a mid-boss. In his story, it appears he traveled back in time, since he's the only Reploid in the time frame and Ciel is the only person who can communicate with him. After winning a battle with Shin Akuma, Zero is transported to either an ethereal-like cloudy area or a hellish area. In the cloudy area, Athena appears and Zero asks her where is he exactly, and she states that he is in Heaven. Zero then tells Athena for her to send him back since he had a mission to accomplish and had no time for this. Athena then engages Zero in a battle to see if he deserved to return to his time, which Zero wins and gets sent back to his own time frame where he re-establishes contact with Ciel. The hell area is similar, but he faces Red Arremer.

When playing as Zero, a WARNING signal will appear on boss pre-battle introductions, including Shin Akuma and a Zero mirror match itself. Zero uses many of his weapons from Mega Man Zero, including the Triple Rod, Buster Shot and Shield Boomerang. He can also use Cyber-elves in some of his attacks.

Onimusha Blade Warriors
Zero is a hidden playable character. Unlike in the Mega Man Zero games, he is voiced by Ryōtarō Okiayu, who voiced Zero in the Mega Man X series.

Rockman X DiVE
Zero appears as a playable character in the July 9th update of Rockman X DiVE. He is an A Rank character (similar to his X series counterpart), and he uses the Z Knuckle and Shield Boomerang attacks.

Cameo appearances

 * In Marvel vs. Capcom 3: Fate of Two Worlds, this version of Zero is mentioned in Zero's (Mega Man X) ending. Zero 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, with the title of his own series.
 * In Ultimate Marvel vs. Capcom 3 one of Zero's alternate colors resemble his Mega Man Zero version.
 * Zero appears as part of the Spirits found in Super Smash Bros. Ultimate.
 * Zero appears in Rockman Xover as Battle Memory and as one of the heroes that OVER-1 has to rescue, being rescued in World 6. OVER-1 also has an armor based on Zero.
 * Zero appears in the artwork from the Z-Saver Battle Chip in the Mega Man Battle Network series.
 * Zero appeared in Street Fighter x All Capcom.

Rockman Zero (manga)
In the manga, Zero is an ancient Reploid found by Lito and his friends that has two identities: Zero, a weak coward, and Rockman Zero, a highly skilled warrior. The reason for this is that Zero uses minimal energy while in his coward state (no helmet), allowing him to unleash his full power while in his Rockman Zero form (with helmet). Zero and Lito travel together and join the Resistance, defeating Neo Arcadia. Zero departs with the Resistance, and Lito returns home.

Fifty years later, Lito created his own Zero. His appearance is the same as the original, except that he has bigger eyes and has a ponytail hairstyle. This new Zero has a 'Hero Chip' installed, giving him a brave attitude to contrast with the original's frail nature.

Mega Man (Archie Comics)
Zero had a brief appearance in the last issue.

Rockman Zero commercials
In Japan, there are four animated featurettes played together with the advertisements for each of the four Zero games.


 * Zero: Neo Arcadian forces attack the monument holding Zero. Zero wakes up and then causes the monument to blow up. He is then seen standing amid the flaming wreckage while holding an unconscious Ciel, contemplating why he was there and who he is (a hint to his amnesia in the game).
 * Zero 2: Zero gets pinned to a wall by Panter Flauclaws. Before Flauclaws opens fire on the Resistance nearby, Zero changes forms to his Energy Form and forces the Mutos Reploid away with the Chain Rod as Ciel watches in awe.
 * Zero 3: A badly injured Zero pants heavily before eventually getting back up to his feet with some effort as Ciel watches, and a giant robot proceeds to collapse and fall apart, causing a huge explosion of dust in the process.
 * Zero 4: a white image of Zero turns his head to the camera and closes his eyes before fading away (subtly foreshadowing Zero's fate at the end of the game) as well as a line saying "All Ze to become...". This commercial is notable for showing the gameplay images before the animation, when it was usually the other way around.

Mega Man Zero Official 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.

Trivia

 * The events during and after Mega Man Zero 4 suggest that Zero has finally died for good; however, to this day, this was not officially confirmed (Mega Man Zero Official Complete Works claim his fate is still unknown). This would later be repeated in Mega Man ZX Advent, where Model Z disappears under similar circumstances.
 * Zero suffers from retrograde amnesia. Retrograde amnesia is characterized by the inability to access memories prior to the time the memory damage occurred. The time period affected can be very variable, leading to forgetting a few days or a lifetime. This type of amnesia do not affect the ability to create new memories. Other types of memory are also intact, such as implicit memory - automatic processes as changing the gear of a car - and procedural memory - a motor memory, such as cycling. Amnesia patients retain their personality and identity, along with their implicit, or procedural, memory. For example a patient with retrograde amnesia can still play a piano (implicit memory), but probably he can't describe his first recital (explicit memory). It is however possible, that patients can recover from it and start to remember up to the point, where the gasps in memory are closed.
 * Zero's speech to Weil before fighting him on Ragnarok is similar to his monologue at the end of the first Mega Man Zero game, just before cutting down a Pantheon.
 * In the prologue for Zero's memory, when Ciel and Milan arrive at the door to Zero's holding chamber in the ruins, a voice speaks out that only Ciel hears, demanding that she not get involved. It is heavily implied that the voice belonged to Zero (presumably preceding his memory loss), with Zero's voice actor even supplying the voice.