X-Force was created by illustrator Rob Liefeld after he started penciling The New Mutants comic book in 1989 with #86. The popularity of Liefeld’s art led to him taking over the plotting duties on the book. With help from writer Fabian Nicieza, who provided the dialogue for Liefeld’s plots, Liefeld transformed the New Mutants into X-Force in New Mutants #100, the book’s final issue. Liefeld and Nicieza launched X-Force in August 1991. Rob Liefeld obtained the name for the series from an unknown artist at a convention a few months prior to its release. With the aid of a multiple-variant poly-bagged card, the book sold a record 5 million copies, and remains the second highest selling American comic book of all time, surpassed only by Jim Lee’s X-Men book that same summer with 8 million copies. The original line-up of the team included Boom Boom, Cable, Cannonball, Domino, Feral, Shatterstar and Warpath. In later issues, X-Force’s roster would include Siryn, Rictor and Sunspot.
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 Mutants.