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The Day of Sigma Title

The opening title of "The Day of Σ"

The Day of Σ is a 25-minute long OVA included in Mega Man Maverick Hunter X, animated by Xebec. It becomes available to the player once the game has been cleared once. The OVA, which serves as a prologue to the game itself, shows the events which lead directly to the beginning of the game and explains Sigma's reasons for rebelling humanity as well as X's powers.

It was also included as a bonus in Mega Man X Legacy Collection and Mega Man X Legacy Collection 2.

Story summary[]

Part One - Gone Berserk[]

Hunters Mechaniloid

The 17th Elite Unit battling a berserk Mechaniloid

The OVA begins with an operation of the Maverick Hunters trying to stop the rampage of a berserk Mechaniloid that is devastating a building. While Sigma, Zero and the rest of the 17th Unit are already on the ground securing the area, X is dispatched from an aircraft via drop point and delivers the first blow at the Maverick Mechaniloid, with it being potent enough to initially force it down and stun it. After X fired another round to fling himself to the side of a building, Sigma then ordered for Chill Penguin to have his unit commence their operation. Before Chill Penguin Company could begin to secure the area, however, the mechaniloid managed to get back up, with no apparent damage from X's attack. It then managed to knock one of Chill Penguin's men down and step on him. Sigma then contacted Zero and asked whether he had a clean shot at the mechaniloid's sole weak spot: the power generator. However, Zero admits the mechaniloid is far too quick to allow for a clean shot, nor can he even get into a close-enough proximity to fire. Chill Penguin then fires some ice particles at one of the mechaniloid's feet, while other members of the unit managed to fire rappel cable launchers to hold it down. Unfortunately, it was proving strong enough to actively resist, with X contacting Sigma to inform them of this development, rushing to back them up. The mechaniloid ultimately broke free via its head-mounted cannons, with the lasers wiping out several of the unit as well as some Maverick Hunter cars, although Sigma managed to evade the attack by jumping up to a tall building. During the course of the attack at the Mechaniloid, the berserk robot manages to get hold of one of the Hunters holding him in front of itself in order to protect its already open power generator just as X arrived. It then tried to escape, although Zero, outraged at it "pushing around" his allies, managed to use the Z-buster to severely damage one of its legs, forcing it to collapse, although it still held the Hunter in front of it. X aims for the generator, yet hesitates to fire because of the other Reploid in the way. As he can't bring himself to shoot, Sigma takes action and uses his beamsaber to destroy the generator, cutting off one of the Reploids' arms in the process, thus shutting the Mechaniloid down.

After the Mechaniloid is defeated, X is scolded by Chill Penguin because of hesitation, claiming there would have been many more casualties if Sigma hadn't stopped the robot. While being carried away on a stretcher, the Reploid who was taken hostage tells X not to be hard on himself, citing it was his own fault for getting captured beforehand. Sigma himself then walks over to X, stating that X's aiming capabilities aren't any different from his own and that he easily could have destroyed the generator and there would have been only a small chance that the Reploid previously held hostage by the Mechaniloid would have been hit by the blast. He tells X that there are moments when Maverick Hunters cannot afford to hesitate in a dangerous situation and have to "pull the trigger" in order to save the many while endangering a few and that the Hunters have sworn to be both, sword and shield of those who are not capable of defending themselves.

Part Two - Hunter Base[]

The unit then returns to the Hunter Base. As Zero and X walk inside the assembly hall, they hear two other Hunters talking about the current Maverick uprisings, specifically that they had just dealt with the seventh Maverick in a month, and that Sigma was currently debriefing Dr. Cain on the current events of the Maverick increases. X then asks what could cause someone to go Maverick and Zero explains that it's due to program errors and shortcuts in the brain of a Reploid which causes someone to go Maverick, the Reploid's unit processing power in general. At that moment, Vile, another member of the 17th Unit, is being brought down the corridor, cuffed and escorted by two Hunter officers.

Sigma Report

Sigma and Dr. Cain discussing the Maverick attacks as well as X's powers.

In another part of the city, Sigma has come to visit Dr. Cain, reporting on this morning's Maverick attack: Specifically, Maverick crime had been steadily increasing to such an extent that now even Mechaniloids are going Maverick. After being asked how X is doing among the Hunters, Sigma explains that he shows tremendous potential on the battlefield, however it's his worrying about others getting hurt that makes him hesitate when decisive action needs to be taken. Cain agrees, but states that it is his worrying which is also part of his potential and power. He explains to Sigma how he found X and how he utilized his blueprints to create the Reploids which can think and act on their own, yet X is the only one who worries about others, a problem that Sigma doesn't have. Sigma expresses surprise that his worrying is the root of X's potential instead of a weakness, with Cain admitting that, under normal circumstances, the ability to worry could prove to be a weakness. For Cain, however, this ability of worrying could be a new connection between robots and humans, but it is at this point unknown whether this will have a good outcome or not. Dr. Cain also mentions that he had extended his life as long as possible to see the ultimate outcome of X's potential regarding the relationship between reploids and humans, although he somberly admits that he probably won't live long enough to see it bear fruit.

Back at the Hunter Base, Zero is reconstructing the earlier situation in which X hesitated to attack via hologram simulation. Rather than X, Zero takes point but hits the Reploid hostage instead of the Mechaniloid's generator, resulting in a 95% success as he only missed the generator slightly. He is then visited by Storm Eagle. The two of them have a short chat about Eagle's duty at the missile base before going back to the assembly hall in which the Operator is holding a briefing about the Mechaniloid attack and that it was most likely a hack attack caused by someone else. Actually, a Mechaniloid's security program shouldn't be so easy to hack, however the Operator states that there is a possibility that someone managed to crack the Hunter Base's systems in order to gain access to the Mechaniloid programs. They also identified one of the sources for the hack attack, which was on 16th Block of the East sector. This surprised Zero and X, due to it being in very close proximity to the Hunter HQ, before inquiring if Sigma had been aware of this. The head operator then informs them that she contacted Sigma regarding this, and that the latter ordered for X and Zero were to investigate. Afterwards, X and Zero are sent to another region of Abel City, from which one of the hack attacks was located.

Part Three - Investigation[]

At Abel City East, 16th Block, a quiet, dark and lonely area of the city, X and Zero investigate the origin of the hack attack, only to find a large number of destroyed Reploids inside the building. The rest of the 17th Unit shows up to investigate the crime scene and the computers there, however all traces have been wiped out, appearing to be an inside job. Sigma arrives as well, asking Zero about what he would make out of the situation. He explains that no matter who did it, the attacker must have had incredible combat skills as every hit the dead Reploids received was directed at a weak spot. Without commenting on Zero's deduction, Sigma leaves and meets with Storm Eagle waiting outside. After nodding towards him, Eagle faces his men and orders them to search the area due to the perpetrator fleeing the scene with the data and thus being a fugitive, as does Chill Penguin's team, leaving Sigma alone at the scene, with the blaring alarms ominously reflecting on his face.

Vile Sigma

Vile is released by Sigma

The next day, another berserk Mechaniloid is causing mayhem in Abel City (presumably among other maverick attacks based on the mass swarm of reports at the base). While the Hunters dispatch in order to stop it, Sigma visits the imprisoned Vile, as Vile asks whether Sigma came to "reprimand [Vile] in person." At the same time, X and Zero rush to the scene of the berserk Mechaniloid. X expresses shock at the increasing frequency of the attacks, while Zero expresses suspicions that the attacks were organized to distract them, and that whoever is causing the recent attacks had a different goal in mind. Zero's suspicions are confirmed shortly thereafter when the two were given the orders to return immediately as Vile has just escaped from his cell. Back at the Maverick Hunter Base, the pink haired operator communicates to Sigma and explains X and Zero are headed back to the detention center and requests Sigma's next order, only to be met with radio silence, causing her concern. Once they arrive, they find a similar scene like the evening before, a hallway full of destroyed Reploids and Zero states that this couldn't have been Vile as he doesn't have that kind of attack capabilities. Zero then noted that the person who did this must have had extensive combat skills, only to flash back to his report to Sigma, causing him to realize that Sigma is the one responsible for both events. X then asks if the one who caused the recent attacks did so as a distraction to release Vile. They then were contacted by Maverick Hunter Base revealing that they've traced the hack origin for the attack: The missile base. However, none of the personnel are able to be contacted due to signal disruptions, and she had even lost contact with Sigma, with Zero expressing a foreboding feeling of what's actually happening.

Part Four - Missile Base[]

Finally, the Hunters managed to track down the location of the hack attack, the Missile Base. Upon arriving, they find Sigma being there as well. In order to hide the signal, the perpetrator used the security systems of the missile base to gain control of the Mechaniloids. Zero, while investigating, then tells Sigma that HQ wasn't able to get in contact with him, with Sigma telling Zero that he had earlier deactivated his comms to "maintain cover", before he ominously states that "none of that matters now." While checking the security terminals, Sigma walks towards Zero from behind, grabbing his saber from his waist. Immediately Zero is able to counter the upcoming attack. Sigma is impressed by Zero having it figured out by now and blocking his attack. Zero explains that only very few have the combat capabilities that precise to have taken out the dead Reploids found at the crime scenes this effectively. Sigma then explains that although he is definitely impressed at Zero's deductive reasoning skills, his admiration for X was the issue, due to X having limitless potential and thus being a great specimen for advancing Reploids.

Sigma then grabs Zero and holds him up, using him as a shield while X is aiming at him. Sigma states that this is exactly the same situation earlier by X before and again, X is hesitating. After taking out Zero with one swift slash of his saber, Sigma grabs the inattentive X, stating that he missed his last chance of stopping his scheme while picking a remote from his belt. After pressing a button on the remote, the base's entire content of missiles are being prepared to be launched, directed at Abel City. Deceiving X into (literally) disarming, he throws him away. X then questions Sigma as to why he's doing these actions, with Sigma then stating he's doing this for the future of Reploids, believing that their potential needs to be put to the "ultimate test." X then realizes that Sigma has caused all these horrific actions from the start which killed several of their own comrades, before Sigma cuts him off by stating that many others will be on his side, summing it up by stating that evolution requires sacrifices to be made, before firing the missiles in front of a horrified X. The Maverick Hunter Base then picks up the unauthorized missile base launch and tried to discover what their target was, before discovering to their shock and horror that Abel City was the target. As X tries desperately to stop Sigma, the missiles destroy large parts of Abel City, one of them hitting Dr. Cain's laboratory, seemingly vaporizing the old man. As this was going on, Cain is reflecting on how Reploids, despite being created by humans, had possessed capabilities far beyond their own, and also ponders whether that was due to the arrogance of mankind before denying it just as the launched missile detonates near his house.

X Light Promise

X promises to use his power to fight for other people's future

While impaled by Sigma's saber, Sigma then tells X that the latter had invited all of this upon himself for what has transpired, due to limitless potential and limitless danger existing within him, and then tells him that rather than an end, it was a beginning for Sigma's new world just as the last remaining missile launched. X then experiences a flashback from his time when he was still under construction by Thomas Light. Light explains that he chose the name "X" for him because it represents a variable in math which can stand for any number and thus unlimited capabilities. At a later point (X is nearly finished except for his Buster), Light states that X is just like humans, but he fears that mankind is not yet ready to accept an artificial being that is so much like a human, as well as fearing his unlimited potential. It is implied that Light during this time is at the very least beginning the process of dying, as X when waking up during this time asks Light if he was alright as he looked tired, with Light himself looking very worn. At the last part of the flashback (X is now complete), Dr. Light apologizes for not being able to see X enter the world because of his age. Upon saying that he gave X the power to think, feel and evolve as he moves on, he states that it is too soon for such a being to be released, while setting up the capsule X is laying in. X promises to use the powers given to him to fight for justice and hope which makes Light cry slightly. Pleased by X's decision, he asks him to fight for the people of the future and guide them to peace before he seals X away.

When the flashback ends, X's unlimited potential is supposedly unleashed for a moment as his energy crystal and left hand begin to glow. He manages to get free of Sigma's hold before dashing at the Reploid, grabbing his face, giving Sigma his signature scars in the process. However, after this action, X seemly shuts down due to the enormous damage he has already taken. Pleased, Sigma comments on X's action and his potential. The OVA closes with Zero regaining consciousness and bringing X back to the Hunter Base while Sigma stares at the devastated city.

Sigma abelcity

"Come and get me X! The time has come to prove your mettle against me. This fight will decide the fate of all Reploids! The battle may be over, but the war is just beginning!"

See also[]

In Other Media[]

While not a recreation of this short, the term "Day of Sigma" was used in a flashback of the events of Sigma turning Maverick in issue 50 of the Mega Man comic book. Its events also have Sigma bombing the city and threatening to launch nukes, which may have been modeled after the missile attack from the end of the OVA. Other differences include that neither Zero nor X actually witnessed Sigma going Maverick first hand (and in the case of the latter was unaware of his going Maverick until Zero told him).


  • Due to Maverick Hunter X being a reboot of the Mega Man X series, the OVA's plot details clash with the original canon such as X and Zero being friends rather than being more like soldier and commander, Sigma becoming Maverick, and Dr. Cain's supposed death at the end of the OVA, making its inclusion with the Mega Man X Legacy Collections nonsensical story wise.
    • That said, the original reasons for how Sigma became a Maverick were indirectly alluded to in the opening flashback for Vile Mode that expanded on the scene where Sigma busted out Vile, where Sigma tells Vile before leaving "My plan requires someone who can go Maverick on their own accord" (with it being heavily implied from that statement that Sigma himself did not actually go Maverick of his own accord).
  • Zero and Storm Eagle are revealed to be friends and allies prior to Sigma's rebellion, referencing the Rockman X manga storyline.
  • At the climax, when X unleashes his unlimited potential against Sigma, the attack he uses is exceedingly similar to the signature finishing attack of the Shining Gundam. As if to nod to this, X and the Shining Gundam's pilot, Domon Kasshu, have the same English voice actor.
  • Sigma's line, "evolution requires sacrifice", is a nod to a similar line by the main antagonist of Mega Man ZX, Serpent.[1]
    • Sigma's missile raid on Abel City in the climax is also similar to Dr. Weil and Copy X authorizing a missile strike on Area Z-3079 in Mega Man Zero 3.
  • All the events in Maverick Hunter X took place in "Abel City". This is a reference to the Bible tale of Cain and Abel, the latter being killed by his brother. This is reflected in the story: Dr. Cain develops Reploids, which are the cause of the destruction of "Abel City".
  • Sigma's actions during the climax for the OVA were later referenced in his character select animation in Mega Man X DiVE.
    • His stabbing of X, or rather, an Armor Soldier disguised as X in the gut resembles this action towards X shortly after launching the nukes at Abel City.
    • His lifting of the Armor Soldier by the face after stabbing him in the gut resembles how he countered Zero's parry attempt of his earlier attack when Sigma reveals his newly Maverick status.
  1. Serpent: "You think I'm doing this all out of fear? That's nonsense! The spirits of the people have given me what I need to obtain the power of Model W! Look at you! You're only able to stand before me today thanks to the power of Model Z absorbed from that red Mega Man! Evolution requires sacrifice! The ones who will determine what needs to be sacrificed are the Mega Men!" - Mega Man ZX