Marvel Comics X-Men spin-off series
X-Treme X-Men is the name of two comic book series published by Marvel Comics, the first from 2001 through 2004, and the second from 2012 through 2013. All 46 issues of the first series were written by Chris Claremont, and featured a globetrotting X-Men team led by Storm. The first 24 issues were drawn by Salvador Larroca, and the final 22 issues were drawn by Igor Kordey.
Volume 2 of "X-Treme X-Men" featured a cast of X-Men characters from alternate dimensions, but led by Dazzler from the main Earth-616 universe. The series was written by Greg Pak. The thirteenth and final issue was released in April 2013.
Volume 1.
Volume 1 of the series originated as part of a revamp of the X-Men line of comics in 2001. Prior to this revamp, Claremont was writing both of the main X-Men titles ("Uncanny X-Men" and "X-Men", the latter of which became "New X-Men", and then ""). He was removed from both core X-titles by Editor-in-Chief Joe Quesada when his storylines fell apart due to editorial interference by the previous editor-in-chief in a failed attempt to capitalize on the first X-Men movie. Quesada offered Claremont the opportunity to write only one of the core X-titles (while allowing new X-writer Grant Morrison to have partial storyline input) or to write a third, new core X-Men title. Claremont chose the latter. That title was dubbed "X-Treme X-Men".
In May 2004, prompted by Grant Morrison's departure from "New X-Men", Marvel felt that another revamp of the X-Men titles was required. As part of this revamp, called X-Men Reload, Chris Claremont returned to writing "Uncanny X-Men". "X-Treme X-Men" was cancelled, with most of its cast and running plotlines being transferred to "Uncanny X-Men". Joss Whedon and John Cassaday's "Astonishing X-Men" replaced it as the third core title.
Team roster.
The X-Treme X-Men contained Storm, Rogue, Gambit, Bishop, Sage (Tessa), Thunderbird (Neal Shaara), Psylocke and Beast as original line up. Psylocke was killed and Beast departed the title in the early goings, and new recruits Lifeguard (Heather Cameron) and Slipstream (Davis Cameron) were eventually added. Later in the series, familiar X-Men characters Cannonball, Lila Cheney, Shadowcat, Magma and Sunspot made regular appearances, with only Cannonball officially joining the team. Evangeline Whedon (a mutant possessing dragon transmorphic abilities) also made numerous appearances.
The title also introduced the character of Red Lotus, who featured heavily in the Australian arc, and was included in issues of the invasion arc.
Story.
The book picked up on many plot threads from Claremont's run on the two main X-Men books. The book is most notable for the death of the popular character Psylocke (now resurrected) in its early issues, and it showed how Beast mutated into his lion-like form.
The first arc (issues 1–4) concerns the quest on the part of Storm and a number of X-Men chosen by her to find Destiny's 13 diaries since none like the idea of having their destinies defined. The arc also introduces Vargas (a new foe who is disturbed by the diaries' predictions of his death), who kills Psylocke in order to test the diaries' predictions. He also heavily injured Beast, which leads to the character's transition to New X-Men.
In the second arc (Savage Land 1–4), the team travel to the Savage Land, where they escort the Saurids to a land where they will not be persecuted. The team tangles and defeats Brainchild (who makes Storm lose control of her powers for a time, bringing out her inner warrior akin to Wolverine's berserker rage). This disturbed her for some time.
The third arc (issues 5–9) involves Gambit in Australia and the warring gangs. The leader of an Australian mafia (known as the Viceroy) dies mysteriously (as if drowning in his own room), and the team must protect his mutant children (Lifeguard and Slipstream who were in the dark as to their real father). The mafia and police accuse Gambit of murder of the gang leader and Bishop and Rogue take charge to clear his name. As a team learns Lady Mastermind and Sebastian Shaw are behind everything, the two villains capture Shaw's former assistant, Sage. Caught between the two villains and a mafia gang war, the team is able to rescue Sage, clear Gambit's name, and protect the now two newest members of the team (Lifeguard and Slipstream).
The Annual (2001) deals with Reavers, the Shadow King, and contains a backup story featuring Kitty Pryde and the threat of Purity. 
The next story arc (issues 10–18) fundamentally changes the title. The team again reunites with Gambit in Madripoor and deals with the invasion of the armies of Khan, an inter-dimensional conqueror. Gambit seeks to obtain Ororo's mother's ruby which was part of a set that, when empowered, could open a portal between dimensions. Since some gems are already missing, Gambit wants to ensure that Ororo's ruby remains safe. However, Gambit is attacked by an other-dimensional warrior named Shaitan, capturing Gambit and stealing the ruby. Shaitan then uses the gems and Gambit's mutant ability to empower them, thus opening the portal for his master, Khan (who, taken by Ororo's powers and beauty, wants to make her his queen). Ororo's X-Men oppose and defeat the invaders, but not before Ororo is seriously injured by Madripoor's ruling crime lord Viper (before the battle) and by Khan's harem (during the battle).
Sage activates all of the powers that Rogue has ever imprinted at once, enabling Rogue to turn the tide of the battle. During the melee, Vargas returns to kill Rogue, after the diaries predicted she'd kill him. As Rogue is attempting to save Gambit, she gets trapped by that same energy that empowers the portal. While they are trapped, Vargas impales them both with a huge broadsword. Rogue uses the strength of Wolverine and the Hulk to overcome her injury, though Gambit remains close to death. Rogue finds Vargas and fights him in order to avenge Psylocke's death and his attempted murder of her and Gambit, as predicted in the diaries. The fight is filmed by a news crew and just as the camera loses power, Rogue is shown standing over Vargas with a sword, poised to strike. It is not actually shown if she kills him or not.
In the midst of the battle in Khan's invasion platform, Lifeguard's power reacts unexpectedly to conceal her identity, leaving her permanently as gold-skinned, bird-like humanoid - revealing her Shi'Ar heritage. Her brother, Slipstream, reacts badly to this and runs off to parts unknown. The team succeeds in defeating Khan as other heroes join in the relief efforts. Storm, Rogue, and Gambit, all near death, are saved with the arrival of Jean Grey, as well as Nightcrawler and Beast. With the help of Beast's surgical expertise, Jean Grey telepathically pulls Storm and Rogue from the abyss of death, and helps Rogue do the same for Gambit (who views this as his one chance for salvation and pleads with Rogue to cross over with him until she pulls him back). Lifeguard and Thunderbird leave the title with this arc, going after Slipstream. Rogue and Gambit take time to recuperate.
In the next few issues (19 and X-Posé 1–2) (arcs 6 and 7), while the team is recuperating, they have dinner with their old teammates. However, it's made quite clear that Xavier's views have changed and a philosophical rift begins. The team deals with the public relations aspect of what they do. The team attempts to keep a mutant documentary on the air, despite efforts to kill it because it is not derogatory. The team succeeds, but another old teammate, Archangel, refuses to allow them to manipulate the media that way.
Issues 20-23 (arc 8) deal with a very young mutant killer seeking asylum at Xavier's Institute. Emma Frost promptly kicks out members Sage and Bishop when they visit because she believes that mutants should police themselves. The team breaks into the mansion to bring the boy to the proper authorities. However, a possessed Emma intercepts them. She is possessed by Elias Bogan, an old acquaintance from the Hellfire Club that she and Sage have met before. After an argument with Professor X elsewhere, Ororo arrives to help her teammates. However, old emotions rise to the surface as Ororo fights Emma Frost. Emma shakes the possession outside the mansion during the fight, but they continue to battle until Storm shows that she's willing to kill Emma and has the ability to do so. Elias Bogan proves to be the threat behind the murders. Storm and Emma pull it together long enough to facilitate the rest of the team's escape, who then stop Bogan, though certainly not for good. The philosophical rift between the two groups of X-Men reaches its peak here when the X-Treme X-Men promise not to return to the mansion again until the dream of peaceful coexistence is, once again, the goal the X-Men, instead of what the X-Treme X-Men believe to be isolationism and possible mutant supremacy.
Kitty Pryde's "Mekanix" miniseries (arc 9) deals with her college life right after she leaves the X-Men and has to face Purity as well as the Sentinels.
The return of Cannonball takes place in issue 24 and issues 25-30 (arcs 10 and 11) contain a story line dealing with Reverend William Stryker, a follow-up to Claremont's 1982 "" graphic novel.
Issues 31-35 (arc 12) see the return of Rogue and Gambit. Storm offers her team's services to the United Nations as a global mutant police force, the X-Treme Sanctions Executive (XSE), wherein mutants will continue to be bound by the human laws, but be policed by other mutants. They succeed as the government is searching for a way to contain the mutant threat. Also, the team fights against powerful mutants who have taken over a town in California and are pushing out the human inhabitants by force. This begins back and forth attacks between mutants and humans, while the team tries to establish peace and bring the aggressors to justice. Though the team doesn't discover it, it's revealed that Elias Bogan is lurking around the edges, influencing events to a degree.
Issues 36-39 (what could be considered arc 13) deal with one of Ororo's missions as part of XSE (i.e., exposing mutant slave trading network and gladiatorial battle arena in Japan). Issues 40-45 again deal with the threat posed by Elias Bogan trying to get his final revenge on the group. Issue 46 (the final issue) shows Kitty Pryde returning to the X-Men fold and the X-Treme team deciding what to do next: return to the Xavier Institute or find a different path.
Volume 2.
"X-Treme X-Men" was relaunched as a new series in 2012 with no connection to the previous volume and a concept similar to "Exiles", featuring Dazzler, Sage, and alternate dimensional versions of familiar X-Men characters, such as Howlett, an alternate Wolverine, Kurt Waggoner, a younger version of Nightcrawler, and Corporal Scott Summers, a Civil War-era African-American version of Cyclops. The series is written by Greg Pak and is a spinoff of his 2011 "Exalted" storyline from "Astonishing X-Men". The series' parallel universe hopping concept is similar to the previous Marvel series "Exiles".
The "X-Termination" event ended the series with issue #13. The storyline crosses over with "Astonishing X-Men" and the "Age of Apocalypse" series.
Story.
The team's mission is to explore the multiverse and hunt down ten evil Xaviers after an inter-universe teleportation awakens them. So far, the team have defeated three: one on a world where mutants are gods, another in a wild-west scenario, and a giant spacewhale being controlled by a Brood Queen. After those two missions, Kurt Waggoner takes a detour to his home reality, with Dazzler and Howlett giving chase. They rescued him with some unexpected assistance from Sage, who has been ambassador of S.W.O.R.D. since she was last seen with the Exiles.
Afterward, they were reunited with Xavier, who since recruited an alternate Cyclops, Dazzler, and Hercules to help. The teams merged and the alternate Dazzler died facing a Witch King Xavier in the next reality, prompting 616 Dazzler to take her costume. In the next reality, Namor fought a Nazi Xavier and Dazzler was able to kill Nazi Xavier. However, Witch King Xavier faked his death and controlled the team's Xavier while resurrecting Nazi Xavier. The three Xaviers fled into another reality, sacrificing the natives to gain more power. The X-Treme X-Men followed