- Boom Boom, previous member of the New Mutants and a rebellious teenager who could produce “Time bombs”.
- Cable, originally a mysterious gun-toting anti-hero mutant, later revealed to possess telepathy and telekinesis, although he continued to rely on firearms.
- Cannonball, a Kentuckian and prior member of the New Mutants who flew at jet speeds and projected a force field around himself when flying. Cannonball was the team's second-in-command under Cable.
- Domino, a world-class mercenary who possessed “luck powers,” allowing probability to turn in her favor and who was Cable’s lover. Later, it turned out that this woman was in fact the shapeshifter Copycat who had taken the place of Domino. The real Domino was still just a friend of Cable and had been imprisoned by Copycat's employers. The real Domino joined X-Force some time after her impostor was exposed.
- Feral, a cat-like mutant with claws, fur, and enhanced senses.
- Shatterstar, a sword wielding warrior from Mojo World who possessed superb fighting skills and limited energy-projection abilities.
- Warpath, an Apache who, like his brother, the short-lived X-Man Thunderbird, possessed super strength and speed.
In issue #3, X-Force would be joined by:
- Siryn, the daughter of the Irish X-Man Banshee who inherited her father’s “sonic scream” and ability to fly.
Later, in issue #15, two former New Mutants who had left before the team's evolution into X-Force joined:
- Rictor, a Mexican who produced powerful shockwaves.
- Sunspot, former New Mutant and citizen of Brazil who absorbed and rechanneled solar energy.
The main opponents of X-Force during its first year were the terrorist Mutant Liberation Front, led by Stryfe, a masked mutant with a mysterious link to Cable. Early issues also featured the wise-cracking mercenary Deadpool, the immortal Externals, and a new version of The Brotherhood of Evil Mutants, the X-Men’s oldest enemy group.
Propelled by Liefeld's art, X-Force became one of Marvel’s best-selling comic books immediately after its debut. The series rivaled The Amazing Spider-Man and Uncanny X-Men in popularity, particularly with the adolescent demographic.[citation needed] Toy Biz responded to X-Force's popularity by introducing an X-Force action figure line alongside its X-Men action figure line.
Writer Mark Waid and painter Alex Ross parodied X-Force and other anti-hero groups from the early 1990s in the 1996 DC Comics miniseries Kingdom Come, which portrayed a future where a generation of violent anti-heroes had replaced the familiar DC characters. Their leader Magog bore an intentional resemblance to Shatterstar and Cable.[citation needed]
Liefeld illustrated the series up to #9 and stopped plotting it after #12 as Liefeld had become increasingly frustrated that he did not own the characters he created and that his art was being used on a variety of merchandise while he received little royalties. Along with six other popular Marvel artists, Liefeld left Marvel Comics in 1992 to form Image Comics.
Mid-1990s: Nicieza and Loeb
X-Force continued with Nicieza writing and Greg Capullo illustrating. Nicieza, who also wrote X-Men (vol. 2), helped plot the X-Cutioner's Song storyline that overlapped into most X-Men related books in the fall of 1992. In that story, Stryfe frames Cable for an assassination attempt on the X-Men’s founder Professor X, leading to a clash between the X-Men and X-Force. The crossover boosted Cable's popularity, despite the character's apparent death in X-Force #18, leading to his own solo series being launched in 1993.
After X-Cutioner’s Song, X-Force continued under Nicieza and Capullo, and later pencilled Tony Daniel. Having temporarily lost their leader, X-Force attempted to develop an identity of their own. The team gradually developed into a dysfunctional family after Cable's return in #25, and the title regularly combined soap opera plot threads, such as romance and Siryn's alcoholism, with violent action. Nicieza fleshed out previously unknown elements of each character's history, including Siryn's family in Ireland [1], Rictor's in Mexico[2], and Cannonball's in Kentucky[3], as well as the mysterious origins of Shatterstar.[4] This period also saw the reintroduction of characters from the group's New Mutants days, such as Rusty and Skids[5], Danielle Moonstar[6], and Cypher and Wolfsbane.[7] A long-simmering sub-plot about Reignfire and the disappearance of Sunspot came to a climax just as the book went on hiatus for the Age of Apocalypse crossover event in 1995.
Due to falling sales,[citation needed] X-Force emerged from the Age of Apocalypse event with a new creative team of writer Jeph Loeb and illustrator Adam Pollina, who significantly revised the team with issue #43. Loeb introduced new team uniforms, had the team move in with the X-Men at the X-Mansion, and placed emphasis on character-driven stories with fewer fight scenes. Rictor quit the team and Cannonball joined the X-Men. Caliban, a super-strong albino mutant who possessed the mind of a child, joined the team. Loeb's stories included revelations about Shatterstar’s origin and the transformation of Boomer (formerly Boom Boom) into the more aggressive Meltdown. Fan response was generally positive.