Mega Man X (Marvel vs. Capcom series)

Mega Man X is a character from the Marvel vs. Capcom series that made his first playable appearance in Marvel vs. Capcom: Infinite. Though he made his technical debut in Ultimate Marvel vs. Capcom 3, but only as downloadable costumes for Zero and Frank West and as a card in the Heroes and Heralds Mode. Though Zero's moveset and voice did not change, X did share some of Zero's abilities and weapons during a few points throughout the Mega Man X series, namely his Z-Saber.

Ultimate Marvel vs. Capcom 3
Mega Man X made an appearance as a collectible ability card in the free DLC mode, Heroes and Heralds. The card's primary ability is to grant players a fixed amount of Hyper Combo Gauge when knocking out an opponent (possibly based on his growth ability) and its secondary effect grants players an air dash. Zero also briefly alludes to X in one of his win quotes, snidely comparing Hawkeye to X both in cunning and in the fact that they lost to Zero.

X was later confirmed to appear as a downloadable costume for Zero (though Zero's moves and animations all still apply) and was released on February 7, 2012. Frank West also has his "Mega Man X" costume from the Dead Rising series as a DLC costume.

Marvel vs. Capcom: Infinite
X appears in the story mode, which starts in Xgard, a fusion of Abel City and Asgard. While most members of X's team are fulfilling their mission to retrieve a special person who knows about the Infinity Stones (Thanos), X and Thor are fighting against Ultron Sigma's army of Xgardians and Ultron Drones, with both lamenting on the damage Ultron Sigma had done overall to their lands. When Ultron Sigma finally appears, the team tries to take him on, but to no successful avail. Captain America boosts X up for a direct attack on Ultron Sigma, but Ultron Sigma easily blocked it and knocked X down. Ultron Sigma was about to slice a downed X, but Iron Man blasts Ultron Sigma on time, only for Iron Man to get knocked down. With the team assembled, Doctor Strange creates a portal and the heroes escape.

The team regroups at Avengers Tower to discuss their plan of attack. With Thanos in their captivity, they use his information to track down the four other Infinity Stones, spread across various parts of the merged universes, and they split to gather them. X is assigned to locate the Power Stone, which is powering the core of Knowmoon. Strider Hiryu and Gamora serve as a distraction while X, Rocket Raccoon, Captain Marvel and Nova go after the stone. X and Rocket stay behind when they encounter a reprogrammed Zero and confront him. They manage to defeat Zero, undoing the rewriting altogether, and they reunite with the others shortly after the defeat of the one ruling Knowmoon, Grandmaster Meio.

After Rocket Raccoon takes the Power Stone, Knowmoon's Gravitron Core, which is filled with the Sigma Virus, is ejected and set on a collision course for New Metro City, where the rest of the heroes are fighting a giant symbiote monster. X's team do what they can to stop the core, but they are unable to damage it or slow its descent and are called back to Avengers Tower after it reached Earth's atmosphere. Thanos hatches a plan to kill two birds with one stone. He teaches Iron Man, X and Zero how to harness the Mind, Time and Power Stones acquired to destroy both the Gravitron core and the symbiote monster plaguing the city. Though they succeed, the destruction of the Gravitron was to close to the city, releasing the Sigma Virus with the heroes at the epicenter of it, infecting everyone. They consult Dr. Light's hologram, but he is unable to deduce a way to slow or halt the infection, the only possible solution being the destruction of Ultron Sigma himself. Reunited, X and Zero gear up together for the fight ahead while Iron Man and Thanos get to work on building a weapon that could deal a decisive blow to the robot tyrant by using the Infinity Stones.

Taking the fight to Xgard once more, X, Zero and the other heroes manage to finally break into the stronghold to confront Ultron Sigma in his lair while Iron Man and Thanos finish making the weapon. Before facing Ultron Sigma, they have to deal with a Sigma Virus-infected Thor, but when Thor is freed from Ultron Sigma's control due to the Soul Stone and Ultron Sigma changes into Ultron Omega, Thor, X, Captain Marvel and Dante team up to weaken him. Iron Man then arrives and summon the new weapon, which he names the Infinity Buster, and gives it to X. X is unable to hold the strength of the buster even when powered up, however with the assistance of Doctor Strange and Morrigan, X was able to be strong enough to fire the Infinity Buster and destroy Ultron Omega, ending the monstrous dictator's rule and the Sigma Virus infection.

Character Select

 * "Starting the mission! Let's go!"
 * "Roger! Reporting for duty!"
 * "Let's fight together, Zero." (Character Select with Zero)
 * "Hands off the buster, got it?" (Character Select with Rocket Raccoon)

Intro

 * "I'd rather not fight such valued heroes." (VS. Avengers)
 * "Let's do this Zero. Together no one can stop us!" (Zero as teammate)
 * "Watch my back, Zero!" (Zero as teammate)
 * "I've always wanted to see a real Shoryuken!" (Ryu as teammate)
 * "After this, let's work with the doc on some upgrades!" (Iron Man as teammate)
 * "Show me what it means to fight for galactic peace!" (Guardian of the Galaxy as teammate)
 * "I told you I can't lend you my buster!" (Rocket Raccoon as teammate)
 * "You can take center stage, Spider-Man." (Spider-Man as teammate)
 * "Thor, let's save both of our homelands!" (Thor as teammate)
 * "Your technology could do so much good." (Thanos as teammate)
 * "For a temporary alliance, this isn't bad." (Villain as teammate)
 * "Even if the enemy is a god, I must complete my mission!" (VS. Thor)
 * "The galaxy needs more than raw strength!" (VS. Nova or Guardian of the Galaxy)
 * "Zero!? Who's controlling you this time?" (VS. Zero)
 * "Some kind of new Maverick? It's going down!" (VS. Ultron or Dormammu)
 * "We're not the same as humans, but we can co-exist with them!" (VS. Ultron)
 * "As long as I stand, there's hope! I will defeat you! (VS. Sigma)
 * Sigma! I'll shatter your plans as I smash your body!" (VS. Ultron Sigma)
 * "Corrupted by the Sigma virus... That's where I come in!" (VS. Ultron Omega)

Victory Text

 * "Zero, I hoped it would never come to this. We should be fighting together as Maverick Hunters!" (to Zero)
 * "I can't claim to protect the whole galaxy... but anything in range of my buster can consider itself guarded!" (to a Guardian of the Galaxy)
 * "That fire I felt from your fists... So your weapons need an emergency cooldown too?" (to Ryu or Chun-Li)
 * "I appreciate what that shield means to you. Now you know what this buster means to my enemies" (to Captain America)
 * "Your past is yours alone. I've lost people along the way too, but we have a duty to keep fighting" (to Captain Marvel)
 * "You've lost. Discard your weapons. ...I wish our worlds could have met without this violence."
 * "You may not be a Maverick, but that doesn't mean I won't take you down!"
 * Whatever you scheme, I'll always be there to stop you! However many times it takes!" (to Sigma)

Trivia

 * One of X's taunt quotes is a reference to Zero's infamous quote from Mega Man X4.