Avengers vs. X-Men (abbreviated AvX) 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. The 12-issue twice-monthly series was first published in April 2012, and features a storyline by Jason Aaron, Brian Michael Bendis, Ed Brubaker, Jonathan Hickman and Matt Fraction, with a rotating team of artists including John Romita, Jr., Olivier Coipel and Adam Kubert.