This stage has 10 cameos in total, all characters from the Mega Man X series. When the stage starts, there are no cameos-however, throughout the match the characters will teleport into the background of the stage to watch the battle. Sometimes they will also teleport away and, over time, new characters take their places. This is mostly random, but characters like X and Zero have the most priority of appearing.
Warning, minor spoilers ahead for X4. Skip Iris and Colonel if you don't want those.
X
The greatest creation of Doctor Light and main character of his series, Mega Man X (or just X) is a Maverick Hunter who fights for peace, though he wishes there were a more peaceful way of protecting both humans and reploids. After teleportation in, X will stand with his hands on his hips and watch with a smile on his face. If a KO is made, X will raise his fist to the air in celebration.
Zero
The greatest creation of Doctor Wily and partner of Mega Man X, Zero is also a Maverick Hunter who fights for peace-though he is more quick to act than X and doesn't spend as much time wishing for a peaceful solution to the war between reploids and mavericks. Zero will stand with his back to the camera, so we get full view of his glorious ponytail. When a KO is made, Zero shows a thumbs up to his opponent.
Axl
The junior Maverick Hunter with the ability to copy the appearance of others, Axl fights with X and Zero to stop Sigma dead in his tracks. Axl will bob from left to right in place, as if imitating a fighting game character, with his guns at the ready. When a KO is made, Axl spins his weapons with his fingers before striking a flashy pose.
Iris
Brother of Colonel and former love interest of Zero, Iris is a member of Repliforce who is unfortunately lost in the Final Weapon incident. Iris will hold her hands behind her and watch the battle with great interest. When a KO is made, Iris brings her hands around from her back to reveal a purple crystal-which she will then toss up into the air before catching it and putting it back behind her. She looks very energetic when doing so.
Colonel
Brother of Iris and one of the two leaders of Repliforce, Colonel is the one who leads the Repliforce to leave Earth, in hopes of living their lives without the humans, and without harming them-but due to seeds of rebellion in the repliforce planted by guess-who, Colonel must be defeated by X (or Zero) in order to stop the Final Weapon from firing at Earth. Colonel will look ahead with not much visible emotion, arms down at his sides. He will politely clap whenever a KO is made.
Alia
The CEO of stopping X dead in his tracks to feed him useless information through his earpiece, Alia is the Navigator of the Maverick Hunters who "helps" by letting X know what's going on in any given situation. Alia will be talking to someone on her earpiece, occupied with something else and not focusing on the match at all-but when a KO is scored, she'll seemingly say "hold on" to them before waving and smiling at the screen.
Douglas
The strangely handsome Douglas is the mechanic of the Maverick Hunters, who proved instrumental during the Eurasia colony incident. Douglas will stand casually and hold a wrench, occasionally tossing it slightly up and making it spin before catching it again. If a KO is made, Douglas reaches his non-wrench fist up, then pulls it back in excitement.
Signas
Signas, the leader of the Maverick Hunters, is the impressive strategist behind all of X's most dangerous missions. Signas will hold his chin up with his hand and simply observe the fight, occasionally nodding. When a KO is scored, he'll smile-this is the most subtle victory animation of the X cameos, but make no mistake-Signas truly appreciated that awesome play you just made.
Sigma
Sigma was once the leader of the Maverick Hunters, but once the Maverick Virus manifested itself inside his body, Sigma felt the need to eradicate humans to make a perfect world for reploids. He now leads the Mavericks and fights with X and Zero
every Tuesday whenever he's up to no good. Sigma will cross his arms around his chest, looking stern. When a KO is made, he throws back his head and laughs, as if to say "lol should've teched"
Vile
Vile is a maverick who works directly with Sigma, who has a lust for destruction and a kink for reincarnation. Vile will stand in place with determination, very much ready for action, with his knee blaster and shoulder canon locked and loaded. When a KO is made, he actually stomps the ground with his feet-Vile lives for destruction, but he'd rather take part in it himself than watch others have all the fun.
When teleportation in, the hero characters (anyone but Vile and Sigma) will teleport in classic Mega Man fashion. However, Vile and Sigma will have two after-images of their character model warp in, combining to form one image, before they themselves appear where that image is.
