Dr. Steven Lang was an employee of the U.S Government charged with discovering the origins of mutation, but His hatred for mutants, He shifted his focus from Genetics to robotics, specifically Sentinels. With funding from the Hellfire Club, Lang created (the MK III Sentinels, a series created with a less efficient cybernetic brain than it's predecessors) the X-Sentinels, His personal pet project, Simulacrum robots with appearances and powers of the original X-Men, Havok and Polaris and set them against the Second generation of X-Men. The resulting battle ended with Jean Grey slamming his mini-fighter into a wall. Lang crawled from the wreckage till He reached His Master Mold in an attempt to assume control of it via a Cerebral interface and ended up in a comatose condition. Lang would return years later as the leader of the Phalanx, the only member to retain his individuality. He would eventually plummet to his death from Mount Everest by the machinations of Cameron Hodge.
In a Grand scheme to exterminate the last remaining mutants, Bastion used the Techno-Organic Virus to infect several living and dead Humans, including Lang. He was given the task of getting in touch with his old government contacts. He used these contacts to go before the United Nations and convince them to set up the Mutant Response Division, while a "mutant terrorist attack" was being staged outside by the Sapien League.
Lang had five hundred M.R.D. units and had deployed several of them to attack the X-Men tracking Hope. Lang was however killed along with Graydon Creed by Hope.