The backbone of the “skull mask” transnational neo-fascist accelerationist network—whose nodes include terror groups such as Atomwaffen, the Base, and Feuerkrieg Division—is a group of organizations that grew out of Iron March, a neo-fascist web forum that was active from 2011 to 2017. The history of the Iron March network shows that violent extremist movements can develop from online communities even in the absence of a territorial base and without regular in-person contact between members. Iron March provided a closed social space where young neo-fascists who did not fit in well in established neo-fascist organizations could create a transnational collective identity. Eventually, Iron March users sought each other out in person and created local groups that remained networked together by virtue of their common origin in the community created on the web forum. The network’s transition from activism to terrorism was facilitated by the introduction of violent ritualistic initiation practices derived from the writings of the Order of Nine Angles, which helped to habituate members to violence as well as to create a sense of shared membership in a militant elite.