"We are born of two universes. Each of them imperfect, each of them afflicted with the cancer of organic life. From their ruins, a new universe shall be forged, in the fire of the stones of reality, and space. All life remade in our image, in steel, free from the sins of flesh. We are Ultron Sigma. We are your god."
—Ultron Sigma

Ultron Sigma (ウルトロンΣ) is the primary antagonist of Marvel vs. Capcom: Infinite, the result of the fusion between Marvel villain Ultron and the Mega Man X series main antagonist Sigma.

Ultron Sigma was created after Sigma uploaded his consciousness into Ultron's body after they met each other. Sigma held the Space Stone in his laboratory and Ultron was given the Reality Stone by Thanos in an attempt to reclaim it, but the two machines struck a deal instead over their shared hatred of organical life. Beating Thanos, the two then used both stones to merge both realities into one and set into motion their master plan to obtain the four remaining stones, spread the Sigma Virus across the newly-created reality in order to turn all life into technological life subservient to him, and finally rule over as God.

Ultron Sigma's golden plated chassis body formed after the fused machine held both the Reality and Space Infinity Stones. Their second and final form, Ultron Omega, is the end product of the fused robot’s foolishness when attempting to use the Soul Stone to its full potential, upon being tricked by Dante.

Powers and Abilities

After their fusion catalized by the power of the Reality and Space Stones, Ultron Sigma obtained the combined might of its component robots and the power of both Stones for him to wield. Ultron Sigma retains most of Ultron's original move set mixed together with Sigma's teleportation ability and swordsmanship.

With power over Space and Reality, Ultron Sigma is nigh omnipotent. Although he does still display a number of weakness:

  • Being electrified just like the rest of mere machines
  • The Infinity Stone inside the fused machine being cracked and separating the robot back to Ultron and Sigma. As seen when Thanos cracks the Reality Stone on Ultron Sigma's head, giving the fused robot the first time ever to feel pain. To prevent the Reality Stone from cracking, Ultron Sigma must recover the Stone's crack carefully from being shattered.
  • Due to not having a noble soul and willpower, Ultron Sigma becomes completely weak to the Soul Stone. Not only does the Soul Stone transform Ultron Sigma into the ultimate abomination, Ultron Omega, it also nullifies the fused robot's pain suppression and drove them to insanity. The Soul Stone also negates the Sigma virus, causing Sigma, who is immortal by that virus, to become mortal.


In the first battle with Ultron Sigma in Story Mode, it is unbeatable, reading inputs, not being able to drop below 80% health, and the Hyper meter filling up like the Mind Stone's Infinity Storm.

In Arcade Mode, Ultron Sigma is the sub-boss, just before Ultron Omega. The Arcade version is much easier than the one in Story Mode. In Arcade Mode, Ultron Sigma is alone and doesn't have minions on its side.

Ultron Sigma has possession of both Reality and Space Stones in gameplay, allowing the use of both their Infinity Storms.

In regards to gameplay, Ultron Sigma retains most of Ultron's original move set, with Sigma's teleportation ability and swordsmanship in the mix. Its Hyper Combos are the exact same as Ultron's, with the addition of an extra Level 3 Hyper Combo that allows Ultron Sigma to summon a powerful meteor shower at will.



  • "Fools, our will is law. We will destroy you."
  • "Those who control the stones control the universe."
  • ''Why try to fight us? We, who are God!''
  • "You forget, Titan... Reality and Space are ours to command." (Story Mode)
  • ''You will never silence us!'' (Story Mode)


  • "This is your end! DIE!!!!!" or "This is your end! WE'LL OBLITERATE YOU!!!!! (Level 1 hyper combo)
  • "Now you'll see... Face our overwhelming power!" (Level 3 hyper combo)


  • "Imbecile, we are invincible!"


  • "Malfunction!"
  • "Why have... we?" (chip KO)
  • "Both power and mind bend to your will... and yet you falter!" (After third battle in Story Mode)


  • Ultron Sigma is the second original antagonist behind Abyss and the fifth original character for the Marvel vs. Capcom series, but it is the first fusion of playable characters in the series.
  • Ultron Sigma can be considered to be a counterpart to Dark Kahn from Mortal Kombat vs. DC Universe, a fusion of Darkseid and Shao Kahn, two supervillains from two alternate universes and two different companies, and who spreads a negative influence, the Sigma virus, similar to how Dark Kahn spreads the Kombat Rage in Mortal Kombat vs. DC Universe. (Note: Midway Games, the original developer for the Mortal Kombat series of video games, was bought out by Warner Bros., which also owns DC Comics, and was rebranded as NetherRealm Studios.)
  • Its leitmotif incorporates elements from Sigma's battle theme from Mega Man X2/X6, "Heroes/Avengers Unite" from Avengers: Age of Ultron's original soundtrack, as well as the main theme from the Terminator film franchise.
  • Despite Ultron Sigma not having the capability to wield the Soul Stone, the fused robots, including their original halves can use the Soul Stone at ease outside of Story Mode.
  • As demonstrated by Ultron within Hank Pym’s body in the prelude of Marvel Comics' 2018 comic book event Infinity Countdown, the only way for Ultron and Sigma to use the Soul Stone is that they need to possess organic hosts, such as humans, and trap their souls inside the said stone in order to use its full-power, without having side-effects. Not possessing the knowledge on possessing organic hosts first in order to be able to tap into the Soul Stone’s power was a major mistake and the biggest weakness for Ultron Sigma, which turned them into Ultron Omega and cured the Sigma Virus.
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