Sigma (Mega Man X)

Sigma is a video game character who is the main antagonist of the Mega Man X video game series. He serves as the final boss in all games except Mega Man X: Command Mission (where he makes no appearances) and Mega Man X8 (appearing as the final boss if the game is played on easy, and as the penultimate boss if the game is set to normal or hard difficulty, since Lumine is fought on normal or hard). Created by Dr. Cain, Sigma was considered the finest of the Reploids and was the first leader of the Maverick Hunters, peace-keeping androids who defend humans against their renegade counterparts. Although he was once honorable, Sigma unexpectedly goes berserk during Mega Man X and rebels against humankind (the cause of this was later revealed to be coming in contact with the Maverick Virus). He defects to the Mavericks and assumes the role of their leader. Under Sigma's command, the Mavericks grow into a legion dedicated to the extermination of the human race. Sigma instigates many of the destructive Maverick Wars, with the Maverick Hunters existing to crush Sigma and his minions.

Sigma appears as a tall, bald humanoid in most of his forms. Although he has been destroyed countless times, Sigma's programming always survives and builds himself a new form, ready to menace the world once again. It is implied that he grows more insane with each transformation. His primary enemies are X, Zero and more recently, Axl.

The Maverick logo is actually a stylized version of the Greek letter Sigma. The symbol for Sigma, "Σ", looks similar to a capital "W" turned at a 90° angle; the letter W is the insignia of Dr. Wily. This does not necessarily mean the logo is a reference to Wily; it might be a reference to how the symbol itself is often used as a symbol for villains of the Mega Man series in general.

Conception and design
Sigma was originally an honorable and selfless leader of the Maverick Hunters, but after his corruption, he became a power-hungry tyrant, although even then, he also genuinely believed that he was doing what was in the best interests of the Reploids. He typically looks down on others and does not hesitate to kill the weak, laughing maniacally at their expense. His previous "protection through aggression" philosophy has mutated following his infection into a huge Darwinism complex, believing that anything that is too weak to progress should be annihilated, a la natural selection. Following his defeat, his further descent into madness transcended death, trying to hold onto any grip in the living world, in any form possible, consumed by the lingering thought of killing X. Amidst his madness, Sigma is a calculating and intelligent individual, and on more than one occasion, turned allies of X and Zero against them, and instigated many of the most destructive events of the Maverick Wars, including the Earth Crisis. Sigma is obsessed with Reploid evolution and superiority, and believes humanity has run its course. Despite his hatred for X and Zero, Sigma once believed they were the future of all Reploids, and would lead them all into a new age. In addition, he also credited X's dedication to justice, as well as his being infected with Zero's virus, as being his primary motivation in his going Maverick, including what ultimately turned out to be his final battle on the Moon.

Appearances in video games

 * In Rockman Xover, Sigma, along with Dr. Wily and other villains from other Mega Man series, join forces to wreak havoc. He is the boss from World 2 and appears in Battle Memory.
 * Sigma appears in Street Fighter x All Capcom.
 * Sigma, with his appearance from Mega Man X4, is one of Chuck Greene's costumes in the Dead Rising 3 DLC mode "Super Ultra Dead Rising 3 Arcade Remix Hyper Edition EX Plus α". He attacks with his scythe and laser eye, and has a special attack called "Sigma Crusher".
 * Sigma appears in Project X Zone 2: Brave New World, the sequel to the first game (where he was only mentioned in name), as an enemy unit.
 * Sigma appeared as an event character in Zombie Cafe.
 * Sigma appears in Marvel vs. Capcom: Infinite, as a playable character via downloadable content. He is also one of the main antagonists of the game, alongside Ultron, with the two using the Infinity Stones to merge and become "Ultron Sigma".

Before Mega Man X
As the former leader of the Maverick Hunters, Sigma was originally the most advanced Reploid of his time. Dr. Cain implanted the latest circuitry designs into Sigma, which were theoretically supposed to prevent him from going Maverick. He was placed in charge of the 17th Elite Unit of the Maverick Hunters, and led them to victory multiple times.

One day, the Maverick Hunters received reports of an overwhelmingly powerful "Red Maverick" that has destroyed an entire squadron of Hunters (the Gamma unit). While investigating, Sigma, along with his unit, tracked it down to an abandoned laboratory (And told his men to stay behind while he takes care of it, reasoning that he "didn't want any more of his people being sacrificed"). It is here that Sigma encountered Zero, the last product of Dr. Wily; Zero carried with him the malicious "Zero Virus" which powered up his abilities and turned him into a "blood-thirsty god of destruction." Sigma was beaten badly by the maddened Zero, but managed to smash the energy crystal in Zero's helmet, which transferred (probably) the Virus directly into Sigma. Zero lost consciousness, and Sigma limped away from the battle, ordering his men to take the body of Zero back for study.

Mega Man X
Sigma's advanced circuitry seems to do its job, as he seemingly remains stable for months after the lab incident. He gradually succumbs to the virus inside of him and grows more volatile. Without warning, he leads a mass revolt among the Reploids, declaring total war on humans. Many Maverick Hunters follow Sigma out of loyalty, leaving Zero in charge of the organization. By this time, he has reformed and become a powerful Maverick Hunter. X, the last creation of Dr. Light and the base model for every Reploid, decides to volunteer and joins Zero. X and Zero battle through the Maverick regime, and it is X who finally destroys Sigma. But though his physical body is scrapped, Sigma's "soul" (the Virus) survives. After the end credits roll, Sigma's face appears on a blue monitor and warns X that he will be back.

Mega Man X2
Just as he said he would, Sigma returns and reassumes leadership of his Maverick forces. He gains a new robot body with the help of the X-Hunters, a trio of vengeful Mavericks who worship him, and becomes Neo Sigma. He also oversees the "Unification" plot, the capture and re-assembling of the remains of Zero, whom he reprograms to kill X in the final battle of the game. Sigma attacks in a new form, armed with clawed hands, but X thwarts his plans and destroys him again. Zero is then restored to his rightful place in the Maverick Hunters and given his own command as leader of Special 0 Unit.

Mega Man X3
Sigma resumes his threat when he infects the Reploid scientist Dr. Doppler, who has developed a revolutionary new anti-virus to repel Sigma's influence. Sigma uses him to stage the revolts in Doppler Town, a utopian city established on the principles of peace. Once Doppler is unmasked as a pawn, Sigma emerges in a heavily-armored form ("Kaiser Sigma"). After he is defeated for the third time, Sigma's "Soul" appears in the form of a wire-frame head and threatens to possess X's body to replace its own. After chasing X through the flaming wreckage of the base, Sigma finally corners him. If Zero is not injured in the game, Zero appears and utilizes the anti-virus created by Doppler to erase Sigma for the time being, else Doppler uses the anti-virus and sacrifices himself to destroy Sigma's programming.

Mega Man X4
Sigma was thought to be suppressed forever after Zero distributed the anti-virus created by Doppler, but it only damaged his virus system horribly. So he hid himself in a dark cloak until he recovers from the previous battle. In the introduction of the game, Sigma acts as a double-agent between the Mavericks and Repliforce, a benevolent squadron of Reploids who assist the Maverick Hunters. Sigma's true motive is to conspire against Repliforce and turn it into a rogue enemy. He stages the bombing of the airborne metropolis Sky Lagoon, which plummets to the ground in the opening of the game. Sigma also hacks into the Maverick Hunters' Mother Computer and infects it with Maverick data, causing their bases to be targeted by Repliforce missiles.

With in-fighting between the Hunters and Repliforce threatening to destroy them both, Sigma increases his influence over the paranoid General of Repliforce. The General, an outspoken advocate of Reploid independence, loses all faith in peace and prepares a satellite laser attack on all humans; fortunately, X and Zero storm the space weapon and stops the General before he can turn its sights on Earth. In the end, Sigma is revealed as the true mastermind and battles Zero himself, armed with a new body and a scythe ("G. Reaper Sigma"). After that form's defeat, however, he occupies two bodies: one large head that appears to be made out of scrap ("Ugly Face Sigma") and one form that holds a massive cannon in a sleek, legless body ("Big Gun Sigma"). Despite his defeat at X's and Zero's hands, he succeeds in part by destroying Repliforce.

Mega Man X5
It is some time before Sigma surfaces again. During his absence, Sigma traced Zero's origins to Dr. Wily, and hatches a plot to unlock Zero's "true" power - the Zero Virus - inside him. Sigma also adapts his programming to completely overwhelm the anti-Virus; the Sigma Virus quickly begins spreading everywhere, turning peaceful machines and Maverick Hunters alike into violent servants of Sigma. The Maverick leader also enlists the help of a Reploid bounty hunter named Dynamo to crash the orbiting space colony Eurasia into the Earth.

Sigma's ultimate goal is to mix his own viral code, which is spread across Earth, with the original Zero Virus, and become all-powerful. Sigma hesitates to kill Zero, intending to make him "remember" who he is and revert back to evil. He fails at this, and both X and Zero defeat Gamma Sigma's giant robot form (which stands several stories high). In the aftermath of the battle, Zero's severed torso lies dormant on the floor. X picks Zero up and tries to get him to respond. The remains of Sigma's head lying nearby suddenly become active and fire an energy laser directly at X and Zero, catching both of them in the chest. As Zero's body falls from X's grasp after Sigma's laser, he manages to fire one last blast from his Z-Buster and finishes Sigma. X is critically wounded in the battle, both from the battle itself and Sigma's final attack (the force of the laser being so strong that it ripped through his body and destroyed his entire lower half and arms), but is eventually rebuilt and returned to the Hunters.

Mega Man X6
Three weeks pass as the human population moves underground to survive the devastation and pollution left by Sigma's last attack (Note that there is a variation stated in one of X5's endings that this is actually three years into the future). Sigma himself is quickly resurrected by a renegade Reploid scientist, Gate, who is angry at the scientific community for rejecting his advanced Reploid designs. He becomes a Maverick after coming into contact with a piece of rubble that contains signatures of the Zero Virus. Gate then uncovers Sigma's remains, and proceeds to rebuild him. However, due to the stress of spreading the Sigma Virus during Mega Man X5's "Colony Incident", Sigma's programming is damaged beyond what Gate can repair, and he is reduced to a half-conscious and barely-functioning wreck of his former self. Gate's work on Sigma's new body is unfinished by the time X confronts him at the end of the game. He seems to remember little more than his rage toward X and Zero, and speaks in a garbled voice. Although it seems as though Gate rebuilt Sigma merely as a backup plan to further his own goals, Sigma is quick to finish Gate off after X and Zero finally defeat him in battle, stating "Oh please, I did not die, nor did I need your help. Now be gone!" This is the only instance in Mega Man X6 that Sigma speaks coherently. This is also the only game in the main X series where Sigma doesn't play a major part in the plot.

Mega Man X7
Sigma reappears yet again to manipulate the hunting organization known as Red Alert. His plan is to use a mysterious young Reploid named Axl to copy DNA signatures of X and Zero, then implant them into destructive war machines. The plan fails when Axl flees Red Alert and sought asylum with the Maverick Hunters. After being defeated, Sigma punches Axl through a wall before vowing to X and Zero to return in a new body. Red, who had been defeated and presumably killed, reppears, and Sigma tries to take over him. Red is revealed to be Axl having taken on Red's form, and then blasts Sigma out of a window.

Mega Man X8
Sigma's next plot was very complex, and it wasn't even him behind the entire scheme. It turned out that Axl was a prototype for a new generation of Reploids. These next generation Reploids possessed advanced copy abilities, and Alia discovered that the copy chips bore copies of Sigma's program among other powerful Reploids. Sigma instigated a new Maverick revolt with these new Reploids as the humans were evacuating Earth in hopes of finding a new home on the Moon. The revolt was stopped, Sigma was completely devastated, and the real mastermind, Lumine, the manager of the project, was revealed and beaten. Before his death, Lumine made a startling claim: according to Lumine, Sigma was dead and not returning. It is believed that the reason Sigma would not regenerate within another body after his final defeat is that he was on the Moon, where the virus might have weakened in the vastness of space and got completely deleted (although he was also defeated in space in Mega Man X4; however, this was on a large battle weapon, not on the Moon). There also might be a lack of available bodies, and his last body was hardly finished. However, his DNA is included in every copy chip in all the next generation Reploids, so technically all new generation Reploids are infected with the Sigma Virus, and possibly Lumine, too. It is unknown if Lumine's claims are true, although his absence in Mega Man X: Command Mission, the entire Mega Man Zero series as well as the entire Mega Man ZX series so far would suggest that he is not coming back.

Marvel vs. Capcom: Infinite
Sigma appears with his original form from Mega Man X as a downloadable playable character, and appears in the story mode as part of an antagonist tag team alliance with Marvel Comics' Ultron. When Thanos and Ultron go to Abel City to obtain the Infinity Stone that was with Sigma, Ultron and Sigma decided to form an alliance, with Ultron destroying Sigma's body to trick Thanos and allowing himself to be infected with the Sigma Virus, taking the Reality and Space Stones from Sigma and Thanos and using them to fuse their worlds and themselves, becoming a singular being known as Ultron Sigma.

Abilities
As the former leader of the Maverick Hunters, Sigma is a capable military leader, described as possessing overwhelming combat power and strategic intelligence. When he turned Maverick, Sigma remains a charismatic leader, and is revived on many occasions by Reploid and Maverick admirers alike. Due to the virus in his circuits, he can survive seemingly anything and always return for more. He is a very powerful Reploid, and is fond of incorporating himself into battle suits which are vastly larger and more powerful than his "regular" form. Sigma is also a skilled manipulator, managing to turn various Reploids, Maverick Hunters, and Mavericks to his side. In fact, there were few instances in the entire series where Sigma wasn't pulling the strings. Sigma himself is one of the strongest Reploids ever created, due to his original role as leader of the Maverick Hunters. His personal energy has been stated to be too powerful to even get an accurate reading. In addition, Sigma's combat skills and analytical abilities were extensive enough that he was able to wipe out several reploids in an efficient manner, as Zero noted when investigating the crime scenes on the days leading to Sigma's revolt.

Sigma is capable of moving at great speed, often able to move faster than the hero can follow, vanishing from sight. Many of his bodies are also capable of teleportation. Sigma seems to favor saber and beam sword weaponry, often integrating powerful sword combos with his blinding speed or teleportation. On several occasions, he projects energy barriers around himself to block incoming attacks. In nearly every appearance, Sigma is capable of discharging enormous destructive blasts or waves of power capable of covering entire battle areas. Sigma's physical strength is considerable. In his first body, during a conflict with the original Maverick Zero, he was able to effortlessly break through Zero's defenses with a round kick, as well as easily toss Zero through the ceiling with a single hand. He has also demonstrated the ability to scale a skyscraper with a single leap.

Sometime prior to Sigma's first defeat at the hands of X, his reploid soul became intermingled with the dangerous Maverick Virus and formed the Sigma Virus. This allowed Sigma's spirit to remain after his body was destroyed, granting him immortality and the ability to return after the destruction of each subsequent body. The Sigma Virus possesses the ability to travel through any material or energy and can manipulate both reploid and organic hosts, even on a planetary scale. Its intangibility allows it to ignore physical assaults and energy attacks, except for those tuned with a Virus Buster to target the Sigma Virus's unique matrix. No solution for the Virus remained ultimately effective during 21XX-22XX, as Sigma demonstrated the ability to adapt to any countermeasure. As the cause of death and suffering for countless innocent lives, Sigma is one of the most dangerous villains in the Classic Mega Man Universe.

Animated Appearances

 * Though not a starring character, Sigma was referred to in an episode of the 1994 Mega Man cartoon, where X, Vile and Spark Mandrill go back in time. His profile, shown by X, mistakenly spells his name as Cigma. The only lines Sigma has is when Vile contacts him near the end of the episode.


 * He also appears in a short unlockable OVA in Mega Man Maverick Hunter X entitled "The Day of Sigma". It shows the Maverick Hunters prior to the events of first Mega Man X game under Sigma's command, before he ultimately revolts. It should be noted that the events in this OVA coincide more with the canon of Maverick Hunter X than with the original game (for example, Dr. Cain is presumably killed in a missile attack on Abel City in the OVA, but mentions of him in the original canon are made all the way up until Mega Man X5).