X-Force, Volume 1: Angels And Demons

There are lines that the X-Men have sworn never to cross. But after the shocking events of Messiah CompleX, Cyclops realizes that some enemies--such as the Purifiers--need to be dealt with permanently - so he changes his strategy. Unfortunately, the X-Men can never know about it as Cyclops sends Wolverine, X-23, Warpath, and Wolfsbane to do the dirty work.