Stephen Lang was an anti-mutant extremist from the Marvel universe and one of the many who would try to utilise the dangerous Sentinel technologies against the so-called "mutant menace".
Stephen Lang was originally part of the US Government, tasked with studying mutation - however his fanatical hatred from mutants led him to focus on robotics, specifically Sentinels.
Lang would mastermind the creation of several X-Sentinels, robotic "clones" of the X-Men, to battle the second version of the X-Men - during his battle Jean Grey slammed Lang's mini-fighter into a wall and knocked him into a coma.
Years later Lang would return as one of the Phalanx, one of the few that had retained their free will - however his return was cut short when he was dragged off Mount Everest by Cameron Hodge.
However Lang would once again cheat death when Bastion resurrected him using a techno-organic virus and he has since return to an active anti-mutant role.