X-Factor I
Group Leader at time of disbandment: Cyclops III
Former Group Leaders: None
Members at time of disbandment: Angel III/Death II/Archangel, Beast, Marvel Girl I, Iceman
Former Members: Cameron Hodge (PR-man), Caliban
First Appearance: X-Factor #1
History: X-Factor was a private organization whose publicly stated purpose was to investigate reports of activities by superhuman mutants, to hunt down and to capture those mutants, and to prevent those mutants from presenting any further threat to normal human beings. However, the true purpose of X-Factor was to locate superhuman mutants who had become victims of persecution by normal human beings, to train those mutants in controlling their superhuman powers effectively, so that they would not prove dangerous to themselves or to others. The original X-Factor was founded by the 5 original X-Men Warren K. Worthington III (as the financier), Scott Summers, Jean Grey, Hank McCoy and Bobby Drake (see: Angel III; Cyclops III; Marvel Girl I; Beast; Iceman; X-Men).
List Of Appearances:
X-Factor #1 (learned that Jean Grey was alive, new team founded, rescued Rusty Collins)
X-Factor #2 (fought Tower, Beast kidnapped by Carl Maddicks)
X-Factor #3 (learned from Tower that Beast had been kidnapped, freed him)
X-Factor #4 (once again fought Tower, this time in an airport, Tower escaped, later fought Frenzy)
X-Factor #5 (fought and defeated by Alliance of Evil)
X-Factor #6 (fought Alliance of Evil and Apocalypse, defeated them)
X-Factor #7 (fought Glow Worm and Bulk)
X-Factor #8-9 (fought Freedom Force)
X-Factor #10 (Mutant Massacre, helped Morlocks against Marauders)
X-Factor #11 (Mutant Massacre, helped Morlocks against Marauders)
X-Factor #12
X-Factor #13
X-Factor #14 (Doctors begins operation on Warren)
X-Factor #15 (Warren seemingly dies in airplane explosion)
X-Factor #16
X-Factor #17 (went to Warren's funeral, Caliban joins team as replacement for Warren, fought The Right, freed Rictor)
X-Factor #18
X-Factor #19 (fought Apocalypse's Horsemen)
X-Factor #20
X-Factor #21 (present at the reading of the will of Warren Worthington)
X-Factor #22 (Headquaters attacked by The Right)
X-Factor #23 (attacked The Right to free the young X-Factor mutants)
X-Factor #24 (Fall of the Mutants; kidnapped by Apocalypse, learned that Apocalypse's fourth Horseman Death was actually their former teammate Angel, fought The Horsemen, defeated by them, Caliban leaves X-Factor to join forces with Apocalypse)
X-Factor #25 (Fall of the Mutants)
X-Factor #26 (Fall of the Mutants; alongside Power Pack fought and defeated Apocalypse's Horsemen, finally accepted as heroes by the public)
X-Factor #27
X-Factor #28
X-Factor #29
X-Factor #30
X-Factor #31 (Marvel Girl and Cyclos fights Freedom Force, Beast unsconscience after kiss from Infectia)
X-Factor #32 (fought Xartans impersonating Avengers)
X-Factor #33 (fought Alliance of Evil)
X-Factor #34
X-Factor #35 (Cyclops and Marvel Girl went out to find Christopher, found him and Jean's nephew and niece at Nanny's)
X-Factor #36 (Inferno; Warren rejoins)
X-Factor #37 (Inferno, fights alot of demons)
X-Factor #38 (Inferno; alongside X-Men fought Goblyn Queen and her demons)
X-Factor #39 (Inferno; alongside X-Men defeated Mister Sinister)
X-Factor #40 (fought Orphan Maker and Nanny)
X-Factor #41-42 (went to England to find the missing Thomas Jones, found him, fought five trolls)

X-Force II
Group Leader at tie of disbandment: Cannonball
Former Group Leaders: Cable
Members at time of disbandment: Meltdown, Domino
Former Members: Shatterstar, Feral, Rictor
First Appearance:
History:
List of Appearances:
X-Force #1-115
X-Force Annual 1-3

X-Force III
See: X-Statix

X-Men
Current Group Leader: Professor X
Former Group Leaders: Changeling (disguised as Professor X) (deceased), Magneto
Current Members: Cyclops III, Iceman, Angel/Archangel, Beast, Marvel Girl/Phoenix IV, Nightcrawler, Wolverine, Northstar, Polaris, Havok, White Queen/Emma Frost
Former Members: Mimic, Banshee, Sunfire, Colossus II (deceased), Thunderbird I (deceased), Ariel/Sprite/Shadowcat, Phoenix III, Longshot, Dazzler, Jubilee, Cannonball, Hector, Sunpyre (deceased), Frenzy, Storm, Rogue, Psylocke (deceased), Gambit, Thunderbird III
First Appearance: "Uncanny" X-Men #1
History: The X-Men is a team of mutants formed by one of the first mutants ever Professor Charles Xavier (see: Professor X). Charles Xavier formed this tieam in order to give other mutants a change in life both to be better accepted in the society, but also a change to do better for all mutants in the world. X-Men has fought numberous of other evil mutants, who didn't believe in Charles Xavier's dream of co-existance between normal human beings and mutants. Among the more famous of evil mutants are Magneto, Mystique, Blob, Avalanche, Destiny, Hellfire Club, Hellions, Proteus, Apocalypse etc. (see: Apocalypse, Avalanche, Blob, Destiny II, Hellfire Club, Hellions, Magneto, Mystique, Proteus II). Other enemies of the X-Men has been normal people like Senator Robert Kelly and Arcade and people who has gained powers not by birth but by other means, villains like Sauron (see: Arcade; Kelly, Robert; Sauron). During the time when Xavier believed his X-Men dead, he recruited a new team of mutants, which he didn't name X-Men but instead New Mutants (see: New Mutants I). Most of these New Mutants later abandonned the dream of Xavier and instead joined Cable's X-Force (see: Cable; X-Force).
Some of Xavier's students have succeded in making a name for themselves, they were appointed government agents in the government-sponsered tema X-Factor (see: X-Factor).
Among other goals which Xavier has accomblished has been to convince former enemies of the team that his dream was the right one, among the people who has benn turned towards Xavier's dream are Magneto, who left the dream again; Rogue, who later joined the X-Men; Emma Frost, who later became co-head of a school for young mutants and Senator Robert Kelly who turned away from his mutant hating campaign, but sadly was killed by a fanatic human being (see: Rogue; White Queen)
List Of Appearances:
"Uncanny" X-Men #1 (In his school for Gifted Youngsters, Professor Xavier, a wheel-chair-bound telepath, mentally summons his s tudents. Like himself, his pu pils are mutants, each born with the capacity for a superhuman power. After the professor tests their abilitires, he introduces them to a new student Marvel Girl. Shortly thereafter, the Cape Citadel missile base is taken over by a lone mutant terrorist - Magneto. Professor X sends the X-Men on their first mission. Guided telepathically from afar by their mentor, The X-Men confront Magneto and, despite his superior power, manage to free the base from his control, but Magneto
manage to escape capture.)
"Uncanny" X-Men #2 (A costumed criminal called the Vanisher  robs banks in broad daylight and escapes, thanks to his power of teleportation. He then announces his intentions to steal the US government's continental defense plans. Professor X w ho suspects that Vanisher iss a fellow mutant, sends the X-Men to stop him, but Vanisher easily escapes them. When he returns to retrieve the ransom for the return of the pans,  Professor X accompanies the X-Men into battel and defeats the Vanisher by mentally robbing him of his memories. With no recollection of his mutant powers, the Vanisher is easily taken into custody)
Tales Of Suspense #49
Avengers Vol.1 #3
"Uncanny" X-Men #3 (Professor X detects a new mutant presence in the area. The X-Men goes to see the new mutant and meets Frederick Dukes aka Blob, at a nearby carnival. The X-Men persuade Blob to retun to the school with them, but he is unimpressed  with the group and declines their invitation to join them. When Professor X attempts to erase his memory of the X-Men's true identities and the location of the school, Blob overpowers the heroes and escapes back to the carnival. Aware for the first time that he is a powerful mutant, Blob takes over the carnival and leades the performers and roustabouts in an attack on Xavier's school. They succeed in capturing the X-Men, but thatnks to the professor's intervension, the X-Men are soon free to stage a successfull conter-attack. Once Blob and his men are defeated. Professor X  erases all of their memories of their encounter with the X-Men)
"Uncanny" X-Men #4 (As the X-Men pratice in their Danger Room, they are unaware of another gathering of mutants on an uncharted Atlantic island: The Brotherhood Of Evil Mutants. Although mutually distrustful, the members are united by their fear of Magneto, whom Quicksilver and Scarlet Witch only serves because Magneto once saved Scarlet Witch from villagers in Transia, who accused her of witchcraft. Magneto and his Brotherhood manage to take over the Central American nation of San Marco. The X-Men enters San Marco in their civilian identities, then attack Magneto's fortress, where they battle the Brotherhood. With the help of Professor X, the X-Men manage to defeat the Brotherhood, Magneto threatens to blow up both the X-Men with a small bomb, and the island of San Marco with a nuclear bomb. Professor X saves the X-Men from the first bomb, but seemimgly loses his powers, while the Brotherhood escapes, Quicksilver unable to go through with Magneto's plan doubles back and defuses the nuclear bomb.)
"Uncanny" X-Men #5 (With the professor no longer able to guide the X-Men, they are pondering their future cource of action when Jean Grey's parents arrive for a brief visit and they must resume their roles as ordinary students. Not long afterwards, Magneto sends a disguised Toad to compete in a televised track meet using his mutant leaping ability. When Toad's superhuman performance causes him to be pursued by an angry mob, the X-Men intervene to rescue him. Magneto's sceme to have the X-Men take Toad back to their base almost succeeds, but Beast recognizes him and pulls off his disguise. As Toad tries to escapes, his partners arrives, and a batte ensues in which the Angel is captured by Magneto. While Magneto questions him in vain at his asteroid base, the X-Men accompany Toad, whose slavish devotion to Magneto drives him to return to the asteroid. Soon Angel is free, and the X-Men and the Brotherhood again joins in battle. The asteroid begins to break up, and the X-Men manage to get away in one of Magneto's ships. Returning home, they learn that Professor X had only pretended the loss of his powers in order to provide them with a "final exam", their first battle fought completely on their own)
Strange Tales Vol.1 #120
Fantastic Four Vol.1 #28
"Uncanny" X-Men #6 (Professor X and Magneto both seek out Namot the Sub-Mariner as a possible mutant. Magneto locates Namor's castle and persuades an Atlantean courtier to suggest to Namor the idea of an alliance with a fellow mutant. No sooner does Namor arrive on Magneto's island, however, that the X-Men appear on the scene. Magneto's power ampflied by a giant magnet, pulls their ship apart, but the X-Men and Professor X reach the shore, only to be attacked by Quicksilver. Before Magneto can launch another attack, however, Namor, recognizing Magneto's true character, turns on him and destroys his control panel. Magneto then turns his powers against Namor, but the fight is interrupted by the X-Men. Magneto and his Brotherhood escapes, while the X-Men and Namor and Scarlet witch begins to fight. Professor X stops the fight. Namor decides that he shall ally himself with neither side of the mutant conflict and is preparing to depart when Magneto once again attacks with his magnetic amplifier. Namor not only resists it's power, but smashed the device with his superhuman strength before returning to the sea. Magneto collects his allies and flies, and the X-Men make their way home)
Amazing Spider-Man Annual 1 (Cameo appearance. While training see Human Torch’s message for Spider-Man.)
"Uncanny" X-Men #7 (Professor X departs on private business, appointing Cyclops debuty leader of the X-Men in his absence. Magneto, meanwhile, has discovered Blob, once more a carnival performer, and has dislodged the mental block Xavier had placed over his memory. Aware once more of his mutant heritage, Blob joins Magneto's group. Cerebro, the professor's device for detecting mutants sounds the alarm and Cyclops rallies the X-Men, even as Magneto challange the team to a fight. The X-Men first fruitlessly combat Vlob, then dodge a hail of torpedoes hurled by Magneto, then attempt to corner Quicksilver. Magneto, however, has merely been using Blob as bait for his trap. As soon as his followers are in the clear, he hurls a fatal torpedo barrage at the gathered X-Men. Incredibly, however, thought Blob takes the full blast, inadvertently shielding the X-Men, he is merely knocked off his feet. A furious Magneto and his Brotherhood make good their escape. Blob no longer trusting mutants of any stripe, elects to remain a carnival freak)
"Uncanny" X-Men #8 (Forced into axction in his civilian identity to save a child's life, Beast is nearly torn apart by a mob and angrily announces that he is quitting the team. He quickly builds a career as an acrobatic wrestler, and soon finds himself facing an opponent known as Unus the Untuchable. Unus, a mutant who cannot be touched against his will, wins their match, then meets with Mastermind in an attempt to join Magneto's Brotherhood. Determined to proves himself to Magneto, Unus relieves a gang of bank robbers of their loot, even as X-Men come on the scene. Unus fights them to a standoff, then escapes. Returning to the base, Beast's erstwhile team find him back in costume and hard at work on a ray weapon which he claims will increas Unus' power. Fearful that he has turned against them, X-Men tries to stop him, but he eludes them, races to Unus' quarters, and exposes him to his ray. Unus is jubilant, but quickly discovers that he can now no longer control his power - he cannot touch anything not even the food and drink he needs to survive. Beast cures him of his affliction with a second application of his ray, exacting his promise to reform and have nothing to do with Magneto. Unus returns to his wrestling career and Beast returns to the X-Men)
"Uncanny" X-Men #9 (The X-Men finds themselves ín Europ, where Professor X is on the trail of Lucifer, who years ago cost him the use of his legs, and has traced him to a cavern hideaway in the Balkans. When he confronts his foe, however, Xavier discovers that Luciher has attuned a gigantic therman bomb to his own heartbeat, so that if he is harmed, the bomb will explodem causing worldwide devastation. Unknown to the mutant heroes, the Avengers are also in the area, tracing mysterious impulses detected by Thor's hammer. As the two team meets, Professor X telepathically warns his students to prevent the Avengers' interference. X-Men and Avengers skirmish, and the young mutants are hard-pressed to stop the more powerful group. Finally Professor X manages to render Lucifer unconscious metally without setting off the bomb. He then contacts Thor by telepathy and explains the situation, ending the battle between Avengers and X-Men. The Avengers depart, and X-Men join their professor in Lucifer's lair, where Xavier and Cyclops together manage to safely defuse the bomb)
Fantastic Four Vol.1 #35
Fantastic Four Vol.1 #36
"Uncanny" X-Men #10 (News reports of a loin-clothed wild man accompanied by a saber-toothed tiger having appeared in the Antartica make the X-Men suspect the presence of another undetected mutant. Although Professor X is certain that the savage is not a mutant, he nevertheless authorizes the team to investigate. Once in Antartica, X-Men discover a hidden tunnel which leads them into a tropical wonderland populated by pterodactyls and other prehistoric creatures. There they are attacked by Swamp Men. Suddnly the savage arrives helping X-Men against the Swamp Men, but they manage to escape with Marvel Girl. The savage who calls himself Ka-Zar and his saber-tooth tiger Zabu joins forces with the X-Men to rescue Marvel Girl. Angel woh scouts ahead is suddenly captured by the Swamp Men as well, and is then reunited with Marvel Girl as both are bound and presented as sacrifices to a tyrannosaurus. Ka-Zar and the others storm the Swamp Men's fortress with the aid of a charging herd of mastodons summoned by the jungle lord, Angel and Marvel Girl, who have evaded the dinosaur, are rescued, the Swamp Men are routed, and X-Men return to the surface, having made a new ally)
"Uncanny" X-Men #11 (Professor X alerts the X-Men to the presence of a new mutant nearby, unaware that the man who refers to himself as "a stranger" has already been contacted by Magneto's Brotherhood. To convince him to join them, Magneto and Mastermind ruthlessly demonstrate their powers of magnetism and illusion on the Stranger, but he retaliates with an energy blast that wrecks Magneto's headquaters and transforms Mastermind into a solid block of inert matter. X-Men arrives to battle the Brotherhood, only to have the Stranger vanish, taking Magneto and Toad with him. Abandoned, Quicksilver and Scarlet Witch decide to leave Magneto's band and return to their home in Europe. Meanwhile, the Stranger and his passangers rematerialize outside the city. When Magneto arrogantly demands to know his mutant power, the Stranger grows to gigantic proportions and renders both Magneto and Toad helpless in coccoons of anti-magnetic membrane. When X-Men arrives with Professor X, the Stranger reveals that he is an alien who had come to Earth to collect samples of mutants, then departs in a blinding light, together with Magneto and Toad. With their most persistent enemy seemingly gone forever, the X-Men returns to Xavier's school ro relax, but only momments kater Cerebro signals the approach of a new menace)
"Uncanny" X-Men #12 (As the X-Men rushes to fortify their school. Professor X relates the origin of their antagonist, his step-brother. After Xavier's father died at Alamagordo, his mother was persuaded to marry her husband's colleague Dr. Kurt Marko. Marko wasn't intertested in Xavier's mother only the family's wealth. Soon after Marko's son Cain from a previous marrage joined the family, and made Xavier's life miserable. After Charles' mother died, Cain caused a laboratory accident, which killed Marko saving the two boys. During their adolescence, Cain was comsumed by jealousy of his step-brother, a top student athlete. Then, while both of them served in Korea, Cain stumbled across the lost Temple of Cytorrak. Ignoring Charles' warning, he picked op the enchanted Ruby of Cytorrak and was transformed into a human juggernaut, just as the temple collapsed around them. Charles escaped, but Cain was buried alive, and now, years laterhe has finally freed himself. Seemingly unstoppable, Juggernaut makes his way inexoarbly through all the scool's defences, then easily sweeps the X-Men aside and confronts his step-brother)
"Uncanny" X-Men #13 (Thanks to his psionic helmet, Juggernaut proves imvulnerable to Professor X's mental powers, as well as to X-Men's phycisal assault. The X-Men fight a desperate holding action against their foe, while Professor X retreats to ready a counterattack. While intensifying his mental energies, he makes telepathic contact with Human Torch and summons him to their aid, while Beast attempts to use the Danger Room's training devices to impede Juggernaut's relentless advance. Finally Guman Torch blinds Juggernaut momentarily, allowing Angel to swoop down and remove Juggernauts helmet. This makes Juggernaut vulnerable to Professor X's phychic blasts, which render jim unconscious. With Juggernaut defeated, Professor X erases Human Torch's memory of the battle and sends him home)
Fantastic Four Annual 3
"Uncanny" X-Men #14 (Even as Professor X grants X-Men some leave time. Dr. Bolivar Trask, a leading anthropologist, makes headline news with his warnings of the growing mutant menace. Xavier arranges to meet Rask in a televised debate, bus his opponent uses the oppotunity to publicly introduce his personal solution to the mutant crisis: the Sentinels, giant robots designed to protect humans from mutants. The Sentinels, reasoning that they can best protect humans, by ruling them, quickly rebels against Trask and takes over the television studio, whereupon Professor summons the X-Men. All but one of th Sentinels fly off with Trask as their prisoner. Then X-Men arrives arrives and engage the remaining robot, who is ultimately felled by a n unknown force. Professor X duduced the location of the other robots' base, and alongside X-Men goes to the base)
"Uncanny" X-Men #15
"Uncanny" X-Men #16
"Uncanny" X-Men #17
"Uncanny" X-Men #18
"Uncanny" X-Men #19
"Uncanny" X-Men #20
"Uncanny" X-Men #21
"Uncanny" X-Men #22
"Uncanny" X-Men #23
"Uncanny" X-Men #24
"Uncanny" X-Men #25
"Uncanny" X-Men #26
"Uncanny" X-Men #27 (Mimic joins the team)
Strange Tales Vol.1 #156
"Uncanny" X-Men #28 (first fought a mind-controlled Banshee and Ogre)
"Uncanny" X-Men #29 (Mimic leaves the team)
"Uncanny" X-Men #30
"Uncanny" X-Men #31
"Uncanny" X-Men #32 (teammates Scott Summers and Jean Grey begins romance)
"Uncanny" X-Men #33
"Uncanny" X-Men #34
"Uncanny" X-Men #35
"Uncanny" X-Men #36
"Uncanny" X-Men #37-39 (fought Factor Three)
"Uncanny" X-Men #40
"Uncanny" X-Men #41-42 (death of Professor X, who at this time unknown to all the X-Men except Jean Grey isn't Professor X. but really their old enemy Changeling)
"Uncanny" X-Men #43
"Uncanny" X-Men #44
"Uncanny" X-Men #45
Avengers Vol.1 #53
"Uncanny" X-Men #46
"Uncanny" X-Men #47
"Uncanny" X-Men #48
"Uncanny X-Men" #49-52 (met Lorna Dane, Lorna is captured by Mesmero, told she was Magneto's daughter, first utilized powers, aided X-Men in defeating Mesmero)
Avengers Vol.1 #60
"Uncanny" X-Men #53
Sub-Mariner Vol.1 #14
"Uncanny" X-Men #54
"Uncanny" X-Men #55
"Uncanny" X-Men #56
"Uncanny X-Men" #57-58 (rescues Lorna from Sentinels)
"Uncanny" X-Men #59
"Uncanny X-Men" #60-61 (Lorna begins living at Xavier's mansion)
"Uncanny" X-Men #62
"Uncanny" X-Men #63
"Uncanny" X-Men #64
"Uncanny" X-Men #65 (Lorna and Havok officially joins the team)
"Uncanny" X-Men #66
Amazing Adventures Vol.2 #12
Marvel Team-Up Vol.1 #4
Amazing Adventures Vol.2 #15
Avengers Vol.1 #110
Avengers Vol.1 #111
Incredible Hulk Vol.2 #172
Captain America Vol.1 #172
Captain America Vol.1 #173
Captain America Vol.1 #174
Captain America Vol.1 #175
Marvel Team.Up Vol.1 #23
Giant-Size X-Men #1 (Professor X recruits Colossus, Storm, Wolverine, Sunfire, Banshee, Nightcrawler and Thunderbird I to try to rescue his X-Men)
"Uncanny" X-Men #94 (most of the older X-Men quits the team, as do Sunfire, the rest of them stays on as the new X-Men, team fights Count Nefaria and the Ani-Men)
"Uncanny" X-Men #95 (Thunderbird dies trying to stop Count Nefaria)
"Uncanny" X-Men #96
"Uncanny" X-Men #97 (fights mindcontrolled Polaris, aka their former teammate Lorna Dane)
"Uncanny" X-Men #98
"Uncanny" X-Men #99
"Uncanny" X-Men #100
"Uncanny" X-Men #101 (Jean Grey is seemingly reborn as Phoenix)
Marvel Team-Up Annual 1
Marvel Team-Up Vol.1 #53
"Uncanny" X-Men #102
"Uncanny" X-Men #103
"Uncanny" X-Men #104
"Uncanny" X-Men #105
"Uncanny" X-Men #106
"Uncanny" X-Men #107-108 (encountered the Impearial Guard of the Shi'Ar Empire)
Iron Fist Vol.1 #15
"Uncanny" X-Men #109 (team first fights Weapon Alpha)
"Uncanny" X-Men #110
"Uncanny" X-Men #111
"Uncanny" X-Men #112
"Uncanny" X-Men #113
"Uncanny" X-Men #114
"Uncanny" X-Men #115
"Uncanny" X-Men #116
"Uncanny" X-Men #117
"Uncanny" X-Men #119
"Uncanny" X-Men #120-121 (fights Alpha Flight for the first time)
Power Man & Iron Fist #57
"Uncanny" X-Men #122-124 (team is tried killed by Arcade in his murderworld)
"Uncanny" X-Men Annual 3
"Uncanny" X-Men #125-128 (with help from Polaris, fights the treat of Proteus, the treat of Proteus is ended when Colossus seemingly destroys the villain)
"Uncanny" X-Men #129 (fought Alpha Flight once more)
"Uncanny" X-Men #130-131 (finds a new mutant named Dazzler, Dazzler becomes an ally in the fight with the Hellfire Club, but refuses to join X-Men)
"Uncanny" X-Men #132
"Uncanny" X-Men #133
"Uncanny" X-Men #134
"Uncanny" X-Men #135
"Uncanny" X-Men #136
"Uncanny" X-Men #137 (Phoenix sacrifice herself on the moon)
"Uncanny" X-Men #138 (Cyclops leaves the team temporarily)
"Uncanny" X-Men Annual 4
"Uncanny" X-Men #139
"Uncanny" X-Men #140
Marvel Two-In-One #69
"Uncanny" X-Men #141-142 (Days of Future Past, X-Men fights Brotherhood of evil Mutants to try to prevent a dark future)
Dazzler #1
Uncanny X-Men #143
Uncanny X-Men #144
Marvel Team-Up Vol.1 #100
Rom #17
Spider-Woman Vol.1 #37
Rom #18
Spider-Woman Vol.1 #38
Uncanny X-Men #145-146 (once again in Arcade's murderworld)
Uncanny X-Men #147
Uncanny X-Men #148
Uncanny X-Men #149
Avengers Annual 10 (alongside Avengers fights Brotherhood of evil Mutants III)
Uncanny X-Men #150 (Cyclops rejoins the team)
Uncanny X-Men Annual 5
Marvel Fanfare Vol.1 #3
Uncanny X-Men #151
Uncanny X-Men #152
Micronauts Vol.1 #37
Uncanny X-Men #153
Marvel Team-Up Vol.1 #118
Marvel Graphic Novel 1
Marvel Fanfare Vol.1 #4
Uncanny X-Men #154
Uncanny X-Men #155
Uncanny X-Men #156 (Cylops learns that Corsair is his father)
Uncanny X-Men #157
Uncanny X-Men #158
Uncanny X-Men #159
Uncanny X-Men #160
Uncanny X-Men #161
Uncanny X-Men #162
Uncanny X-Men #163
Uncanny X-Men #164
Uncanny X-Men #165
Uncanny X-Men #166
Uncanny X-Men #167
Uncanny X-Men Annual 6
Incredible Hulk Vol.2 #278
Incredible Hulk Vol.2 #279
Contest of Champions #1
Contest of Champions #2
Contest of Champions #3
Marvel Two-In-One Annual 7
Special Edition X-Men #1
Firestar #1
Uncanny X-Men #168
Amazing Spider-Man Vol.1 #242 (flashback, to original X-Men fighting Mad Thinker)
Marvel Graphic Novel 5
Uncanny X-Men #169
Uncanny X-Men #170
Uncanny X-Men #171 (Rogue joins the team)
New Mutants Vol.1 #7
Wolverine Vol.1 #4
Uncanny X-Men #172
Uncanny X-Men #173
Uncanny X-Men #174
Uncanny X-Men #175 (Cyclops marries Madelyne Pryor)
Marvel Team-Up Vol.1 #135
Moon Knight Vol.1 #35
Uncanny X-Men Annual 7
Uncanny X-Men #176
Uncanny X-Men #177
Uncanny X-Men #178
Marvel Super-Heroes Secret Wars #1-12
Uncanny X-Men #179
New Mutants Vol.1 #13
X-Men and the Micronauts #1 (Protect the Professor when Karza attacks him. Agree to help the Micronauts.)
X-Men and the Micronauts #2 (Fight the mentally controlled versions of the X-Men and are defeated.)
X-Men and the Micronauts #3 (Are used by the Entity to fight Dog Soldiers. Once able, attempts to escape with the Micronauts.)
X-Men and the Micronauts #4 (Make it back to Earth and fight the New Mutants, who are under the Entity’s control. Professor X is able to trick the Entity and it is destroyed.)
New Mutants Vol.1 #14
Uncanny X-Men #180
Uncanny X-Men #181
Uncanny X-Men #182
Uncanny X-Men #183
Marvel Graphic Novel #12
Firestar #2
Uncanny X-Men #184
Uncanny X-Men #185
Uncanny X-Men #186
Uncanny X-Men #187
Uncanny X-Men #188
Marvel Team-Up Vol.1 #150
Uncanny X-Men #189
Uncanny X-Men #190
Uncanny X-Men #191
Uncanny X-Men #192
Uncanny X-Men Annual 8
Rom #65
Rom #66
Dazzler #38
X-Men & Alpha Flight Vol.1 #1-2
Uncanny X-Men #193
Uncanny X-Men #194
Secret Wars II #1
Uncanny X-Men #195
Uncanny X-Men #196
Uncanny X-Men #197
Serect Wars II #5
Uncanny X-Men #198
Uncanny X-Men #199 (Phoenix III joins the team)
Uncanny X-Men Annual 9
Uncanny X-Men #200 (Magneto is made head of X-Men)
Uncanny X-Men #201 (fight over leadership of the X-Men between Cyclops and Storm, Storm wins and Cyclops leaves the team with his wife and his newborn son)
Marvel Fanfare Vol.1 #33
Alpha Flight Vol.1 #33
Heroes For Hope Starring the X-Men #1
Secret Wars II #7
Uncanny X-Men #202
Secret Wars II #8
Uncanny X-Men #203
Secret Wars II #9
Uncanny X-Men #204
X-Factor #4 (flashback)
Uncanny X-Men #205
Uncanny X-Men #206
Uncanny X-Men #207
Uncanny X-Men #208
Uncanny X-Men #209
Uncanny X-Men #210-211 (Mutant Massacre, Colossus, Nightcrawler and Shadowcat badly wounded by Marauders)
Uncanny X-Men Annual 10 (Longshot joins the team)
Uncanny X-Men #212
Uncanny X-Men #213
Uncanny X-Men #214 (Psylocke joins the team)
Mephisto Vs. ... #3-4
Uncanny X-Men #215 (Dazzler finally joins the team)
Uncanny X-Men #216
Uncanny X-Men #217
Uncanny X-Men #218
Uncanny X-Men #219 (Havok rejoins team, Polaris is attacked by Marauders and comes under the mental control of Malice)
Fantastic Four Vs. The X-Men #1-4
X-Men Vs. The Avengers #1-4
Uncanny X-Men Annual 11
Uncanny X-Men #220
Uncanny X-Men #221 (fought Marauders lead by Polaris)
Uncanny X-Men #222
Uncanny X-Men #223
Uncanny X-Men #224
Incredible Hulk Vol.2 #340
Uncanny X-Men #225
Uncanny X-Men #226
Uncanny X-Men #227
Uncanny X-Men #228
Uncanny X-Men #229
Uncanny X-Men #230
Uncanny X-Men #231
Uncanny X-Men #232
Uncanny X-Men #233
Uncanny X-Men #234
Uncanny X-Men Annual 12
Alpha Flight Vol.1 #61
Uncanny X-Men #235
X-Factor #38 (Inferno; alongside X-Factor fought Goblyn Queen and her demons)
X-Factor #39 (Inferno; alongside X-Factor defeated Mister Sinister)
Uncanny X-Men Annual 13 (fought Serpent Society)
Uncanny X-Men #275-277 (fought Warskrulls)
Uncanny X-Men #379 (all mutants around the world loses their powers temporarily)
Uncanny X-Men #390 (Colossus sacrifice himself in order to cure the world of the Legacy Virus)
Uncanny X-Men #391 (after having returned to the "land of the living" Cyclops takes on a picnic with his father to try to get more in touch with each other)
Uncanny X-Men #392 (Jean Grey finds new members of a mission to Genosha, among the new members for this mission is Sunpyre (the younger sister of Sunfire), Frenzy, Hector, the canadian superhero Northstar and former member Dazzler)
Uncanny X-Men #393
Uncanny X-Men #394
Uncanny X-Men #395
Uncanny X-Men #396
Uncanny X-Men #397
Uncanny X-Men #398
Uncanny X-Men #399
Uncanny X-Men #400
Uncanny X-Men #401
Uncanny X-Men #402
Uncanny X-Men #403
Uncanny X-Men #404
Uncanny X-Men #405
Uncanny X-Men #406
Uncanny X-Men #407
Uncanny X-Men #408
Uncanny X-Men #409
Uncanny X-Men #410
Uncanny X-Men #411
Uncanny X-Men #412
Uncanny X-Men #413
Uncanny X-Men #414
Uncanny X-Men #415
Uncanny X-Men #416
Uncanny X-Men #417
Uncanny X-Men #418
Uncanny X-Men #419
Uncanny X-Men #420
Uncanny X-Men #421
Uncanny X-Men #422
Uncanny X-Men #423
Uncanny X-Men #424
Uncanny X-Men #425
Uncanny X-Men #426
Uncanny X-Men #427
Uncanny X-Men #428
Uncanny X-Men #429
Uncanny X-Men #430
Uncanny X-Men #431
Uncanny X-Men #432
Uncanny X-Men #433
Uncanny X-Men #434
Uncanny X-Men #435
Uncanny X-Men #436
Uncanny X-Men #437
Uncanny X-Men #438
Uncanny X-Men #439
Uncanny X-Men #440
Uncanny X-Men #441

X-Men 2099 (Xi'an's team)
See: Appendix, Futures, 2099, X-Men 2099 (Xi'an's team)

X-Men 2099 (Zhao's team)
See: Appendix, Futures, 2099, X-Men 2099 (Zhao's team)

X-People
See: MC-2 Handbook, X-People

X-Ray
Real Name: James "Jimmy" Darnell
Occupation: Professional criminal, fuel propulsion engineer
Other Aliases: None
Place Of Birth: Unrevealed
Marital Status: Single
Known Relatives: Ann Darnell (sister, aka Vapor)
Group Affiliation: U-Foes, "Big House escaping"
Source Of Powers: Exposure to cosmic radiation
Powers: Has the ability to project hard radiation from his body. He is immune to physical injury, but can't resume human form
First Appearance: Incredible Hulk Vol.2 #254
List Of Appearances;
Incredible Hulk Vol.2 #254 (took trip in space to gain powers, fought Hulk)
Incredible Hulk Vol.2 #275-277 (tried to get revenge at Hulk, defeated)
Incredible Hulk Vol.2 #304-305 (met Hulk in other dimension, defeated)
Avengers Vol.1 #304 (with U-Foes, returned to earth, fought Avengers)
Avengers West Coast Vol.2 #53 (Acts Of Vengeance, with U-Foes,  fought West Coast Avengers)
Darkhawk #6 (alongside U-Foes fought Captain America, Daredevil, Darkhawk and Portal)
Incredible Hulk Vol.2 #397-401
She-Hulk Vol.3 #5 (joined forces with Mad Thinker to escape the "Big House")
She-Hulk Vol.3 #6 (fought Southpaw, She-Hulk and Yellowjacket, defeated)

X.S.E II
Current Group Leader: Storm
Former Group Leaders: None
Current Members: Bishop, Sage, Cannonball, Thunderbird III
Former Members: Gambit, Rogue, Shadowcat, Beast, Psylocke (deceased), Lifeguard, Slipstream
First Appearance (as "X-Treme" X-Men):
First Appearance (as X.S.E)
History: Splinter-group of X-Men formed by Storm to hunt for the 13 volumes of Irene Adler's diaries (see: Destiny II)
List Of Appearances:
X-Treme X-Men #1
X-Treme X-Men #2
X-Treme X-Men #3
X-Treme X-Men #4
X-Treme X-Men #5
X-Treme X-Men #6
X-Treme X-Men #7
X-Treme X-Men #8
X-Treme X-Men #9
X-Treme X-Men #10
X-Treme X-Men #11
X-Treme X-Men #12
X-Treme X-Men #13
X-Treme X-Men #14
X-Treme X-Men #15
X-Treme X-Men #16
X-Treme X-Men #17
X-Treme X-Men #18
X-Treme X-Men #19
X-Treme X-Men #20
X-Treme X-Men: X-Pose' #1
X-Treme X-Men: X-Pose' #2
X-Treme X-Men #21
X-Treme X-Men #22
X-Treme X-Men #23
X-Treme X-Men #24
X-Treme X-Men #25 (God Loves, Man Kill II)
X-Treme X-Men #26 (God Loves, Man Kill II)
X-Treme X-Men #27 (God Loves, Man Kill II)
X-Treme X-Men #28 (God Loves, Man Kill II)
X-Treme X-Men #29 (God Loves, Man Kill II)
X-Treme X-Men #30 (God Loves, Man Kill II)
X-Treme X-Men #31 (Intifada)
X-Treme X-Men #32 (Intifada)
X-Treme X-Men #33 (Intifada)
X-Treme X-Men #34 (Intifada)
X-Treme X-Men #35 (Intifada)
X-Treme X-Men #36
X-Treme X-Men #37
X-Treme X-Men #38
X-Treme X-Men #39
X-Treme X-Men #40
X-Treme X-Men #41
X-Treme X-Men #42
X-Treme X-Men #43
X-Treme X-Men #44
X-Treme X-Men #45
X-Treme X-Men #46
Uncanny X-Men #444
Uncanny X-Men #445
Uncanny X-Men #446
Uncanny X-Men #447
Uncanny X-Men #448

X-Statix
Group Leader at time of disbandment: The Anarchist (field leader) (deceased)
Former Group Leader: The Coach/The Arm (leader) (deceased), Zeitgeist III (field leader) (deceased), Mister Sensitive/The Orphan (field leader) (deceased), Henrietta Hunter (field leader) (deceased)
Members at time of disbandment: Doop (deceased), Mister Sensitive/The Orphan (deceased), Vivisector (deceased), Dead Girl (deceased), Venus Dee Milo (deceased)
Former Members: Sluk (deceased), Battering Ram (deceased), Gin Genie (deceased), La Nuit (deceased), Plazm (deceased), Bloke (deceased), Saint Anna (deceased), U-Go Girl (deceased), Spike II (deceased), Mysterious Fanboy (deceased), Phat (deceased), El Guapo (deceased)
First Appearance (as X-Force): X-Force #116
First Appearance (as X-Statix): X-Force #129
List of Appearances:
X-Force #116 (The team goes on a mission to Africa where Sluk is killed. At a press conference, Anarchist is introduced as his replacement. The Coach gives the team a mission to rescue a boy band held hostage in a music studio, on this mission Battering Ram, Gin Genie, La Nuit, Plazm and Zeitgeist are killed.)
X-Force #117 (While U-Go Girl and Anarchist argue about who should be the new leader the Coach introduces Bloke, Vivisector, Phat, Saint Anna and the Orphan as the new members. The Orphan is named new leader.)
X-Force #118 (The Orphan is having doubt whether or not he should be leader. U-Go Girl says she is ready to take over any minute. X-Force is sent to Bastrona to rescue Paco Perez, The Orphan's leadership abilities are put to a real test. Bloke is shot in the back by helicopters and dies)
X-Force #119 (Saint Anna is killed. Orphan rescues Paco. Coach reveals that the plan was for Paco to be killed and his powers studied. Orphan opposes Coach and Anarchist, Phat and Vivisector side with him. Orphan takes Paco to stay with Saint Anna’s father. Coach offers U-Go Girl a chance to lead the team if she kills Orphan.)
X-Force #120 (Coach is revealed to be setting up a fight between members and to have been responsible for the massacre on the Sonic TV mission. Edie turns against Coach and she, Orphan and Wolverine stop him and Smoke and Succubus. Edie kills Coach.)
Thunderbolts #57 (The team is seen among the superhumans held captive by Graviton.)
X-Force #121 (Anarchist votes against the Spike joining the team, which causes the Spike to confront him. Orphan ponders his relationship with Edie. Spike Freeman convinces Phat and Vivisector that they need to fight amongst the team for attention. Lacuna pulls pranks on them and tries to get them to let her join.)
X-Force #122 (Phat and Vivesector drunkenly endanger the audience of a TV show, and are happy with the publicity it brings them. Anarchist agrees to let the Spike join if the others let Lacuna join, but Lacuna changers her mind and gets a TV show instead.)
X-Force #123 (Doop accidentally sucks the team into himself and they are confronted by nightmarish images. Doop pulls himself into himself and saves them all.)
Brotherhood #8 (In flashback, the team is revealed to have destroyed the Brotherhood’s cell in Tokyo.)
X-Force #124 (Edie’s powers are acting up and Guy talks her into returning home to see her family.)
Brotherhood #9 (During a parade, the team is attacked by the Brotherhood. The team manages to kill the attackers, but also the three members who actually were looking for X-Force’s help.)
X-Force #125 (Return from mission gone wrong, including civilian casualties. Told by Spike Freeman that they should change their name. Guy, Edie and Tike recruit Dead Girl and see “the specter of death”, each thinks it is pointing at them. The team prepares to go on a mission that they will intentionally lose for the CIA.)
X-Force #126 (The team arrives at the Mars 2010 space station and is ambushed by the Bush Rangers.)
X-Force #127 (Continue fighting Bush Rangers. Tike, Edie, Guy and Doop teleport to escape the CIA and end up trapped in aspace shuttle with an escape pod that can’t fit them all. The Spike is replaced by Tray, posing as him.)
X-Force #128 (Tike, Guy and Edie roll a die to decide which one of them has to be left behind to die. Tike weighs the die so he loses and is left behind. The team is able to go back for him. The real Spike returns and is killed by Tray. Edie is also wounded by him and dies.)
X-Force #129 (The team deals with the aftermath of Edie’s death. They attend a farm team exhibition to scout for potential replacement members. Orphan announces that the team is becoming X-Statix.)
X-Statix #1 (X-Statix is looking for new members for the team. Cockcrew is among the ones they see, but rejects him. Venus Dee Milo is accpeted as the newest member of the team)
X-Statix #2
X-Statix #3
X-Statix #4
X-Statix #5
X-Statix #6
X-Statix #7
X-Statix #8
X-Statix #9
X-Statix #10
X-Statix #11
X-Statix #12
X-Statix #13
X-Statix #14
X-Statix #15
X-Statix #16
X-Statix #17 (Phat is killed)
X-Statix #18 (El Guapo is killed)
X-Statix #19
X-Statix #20
X-Statix #21
X-Statix #22
X-Statix #23
X-Statix #24
X-Statix #25
X-Statix #26 (all remaining members of the team decided to disband the team, and before leaving the superhero business, they decides to take one last mission. Sadly this mission also proves to be the final thing for the members of the team as all members dies)
Final Appearance: X-Statix #26

"X-Treme" X-Men
See: X.S.E II

Xartans
See: Appendix, Alien Races, Xartans

Xavier, Brian
Real Name: Brian Xavier
Occupation: Scientist
Other Aliases: None
Place of Birth: Unrevealed
Marital Status: Married
Known Relatives: Sharon Xavier (wife, deceased), Charles Francis Xavier (son, aka Professor X)
Group Affiliation: None
Source of Powers: None
Powers/Abilities:
Cause of Death: Killed in an explosion
First Appearance: "Uncanny" X-Men #12
History:
List of Appearances:
"Uncanny" X-Men #12 (mentioned only. Flashback to funeral)
Final Appearance: "Uncanny" X-Men #12

Xavier, Sharon
Real Name: Sharon Xavier Marko
Occupation: Housewife
Other Aliases: Sharon Marko
Place of Birth: Unrevealed
Marital Status: Married
Known Relatives: Brian Xavier (first husband, deceased), Charles Francis Xavier (son, aka Professor X), Kurt Marko (second husband, deceased), Cain Marko (step-son, aka Juggernaut)
Group Affiliation: None
Source of Powers: None
Powers/Abilities:
Cause of Death:
First Appearance: "Uncanny" X-Men #12
History:
List of Appearances:
"Uncanny" X-Men #12 (flashbacks only)
Final Appearance: "Uncanny" X-Men #12

Xemnu
Real Name: Xemnu
Occupation: Ruler of home planet, TV star
Other Aliases: The Titan, Richmond Wagner, Amos Moses
Place Of Birth: Unidentified "alien" planet
Marital Status: Single
Known Relatives: None
Group Affiliation: None
Source Of Powers: Alien genetic structure
Powers: Gifted, superhuman strength, stamina and durability, enhanced speed, telepathy, hypnosis, can place mental blocks on others, project concussive blasts, levitation, animate unliving objects, create "atmospheres" a protective sphere of psionic energy which he can use to fly with himself within it
First Appearance: Journey Into Mystery #62
List Of Appearances;
Journey Into Mystery #62
Marvel Feature #3
Defenders #12
Incredible Hulk Annual 5 (fought Hulk)
Marvel Two-In-One #78 (as Amos Moses head of movie studio, used producer Ted Silverberg in his plot to enslave the earth, defeated by Thing and Wonder Man)
Sensational She-Hulk #6-7 (After being defeated by She-Hulk, given to Enilwen a huge alien baby as a toy bear)
Sensational She-Hulk #42-43 (revealed how he'd escaped Enilwen using subtle hypnosis, so that Enilwen would collect rocks instead of bears. Planned to put She-Hulk under his direct hypnotic control, and sell her as a slave to an endless number of sleazy aliens, who would take pictures of her for the Marvel Illustrated Swimsuit Edition. But Louise Mason knocked him over the head with a giant wrench, and down he went.)

Xennus
See: Appendix, Other Dimensions, Xennus

Xenos
Real Name: Sgt. Gwenn
Occupation: Police officer turned xenophobic terrorist
Other Aliases: None
Place Of Birth: Unrevealed
Marital Status: Single
Known Relatives: None
Group Affiliation: None
Source Of Powers: None; wore a rat costume equipped with claws
History: Xenos is a xenophobic American intent on expelling "outsiders" from the country
First Appearance: Moon Knight Vol.1 #15
List Of Appearances:
Moon Knight Vol.1 #15 (made assassination attempts on foreign diplomats, fought and unmasked by Moon Knight)

Xeon
Real Name: Unrevealed
Occupation: Leader of the Legion street gang
Other Aliases: None
Place of Birth: Harlem, New York
Marital Status: Single
Known Relatives: None
Group Affiliation: The Legion
Source of Powers: None
First Appearance: Falcon #2
List of Appearances:
Falcon #2 (attempted to make peaceful march with the Legion, best friend Jimmy killed; declared war against the Falcon)
Falcon #3 (captured President Reagan)
Falcon #4 (threatened to kill the President; convinced by Falcon to talk things out with him)

Xeronian
See: Appendix, Alien Races, Xeronian

Xi'an
See: Appendix, Futures, 2099, Xi'an

Xixix
See: Appendix, Alien Races, Xixix

Xorn
Real Name: Unrevealed
Occupation: Professional criminal
Other Aliases: Magneto (imposter)
Place of Birth: Unrevealed
Marital Status: Unrevealed
Known Relatives: None
Group Affiliation: X-Men, Brotherhood
Source of Powers: Genetic mutation
Powers/Abilities:
Cause of Death:
First Appearance (as Xorn): New X-Men Annual 2001
First Appearance (as Magneto imposter): New X-Men #146
History:
List of Appearances:
New X-Men Annual 2001 (as Xorn)
New X-Men #122 (as Xorn. Scott Summers AKA Cyclops, comes to pick Xorn up)
Final Appearance:

Xxar, Xxan
Real Name: Xxan Xxar
Occupation: Ambassador
Other Aliases: None
Place of Birth: the planet Xix
Marital Status: Unrevealed
Known Relatives: None
Group Affiliation: None
Source of Powers: None
First Appearance: Fantastic Four Vol.1 #261
List of Appearances:
Fantastic Four Vol.1 #261 (schemed to kill Galactus using gun that would devour his body and armor, as revenge on him for devouring his home planet; backed down out of fear that his attack would fail)