The X-Men are a superhero team of mutants founded by Professor Charles Xavier. They are dedicated to helping fellow mutants and sworn to protect a world that fears and hates them.
Fantomex then made sporadic guest appearances with the X-Men until October 2010 when he has a permanent member of the new Uncanny X-Force with Rick Remender and Jerome Opeña as the creative team. That series ran for 35 issues and explored Fantomex's background and developed his character.
Avengers vs. X-Men (AvX or AvsX) is a 2012 crossover event that was featured in comic books published by Marvel Comics.The event, consisting of an eponymous limited series and numerous tie-in books, involves the return of the Phoenix Force and the subsequent war between the Avengers and the X-Men.