Mr. Carter

Mr. Carter was the Commonwealth's first known synth infiltrator, responsible for several murders in Diamond City that would subsequently be known as the Broken Mask incident of 2229.

Background
According to eyewitness Eustace Hawthorne, one May evening Carter joined a group of individuals at the town's central bar. Claiming to be from out west, he struck up conversation, sharing stories about the state of the Commonwealth with the rest of the individuals that had gathered at the establishment.

The group enjoyed several drinks together over the course of the evening, until Eustace noticed Mr. Carter's smile suddenly faded, and his cheek began to twitch. As his cheek began to twitch, Mr. Carter unexpectedly pulled out his revolver and, without emotion or hesitation, shot the bartender Henry in the head. With his cheek still twitching, Carter continued to execute several other individuals. As the city guards arrived and opened fire, Carter continued his frenzy, "tossing people left and right." He was eventually "put down" by security.

Inspection of his corpse revealed chunks of plastic and metal, revealing Carter was not Human but instead an advanced synth created by the Institute. When the Director of the Institute learned of the situation, they were furious. Carter had been not approved for field testing and was sent to the surface without authorization. As the incident threatened decades of work to keep the organization "out of the spotlight" in the Commonwealth, the Director sought to identify those responsible.

Appearances
Mr. Carter is mentioned only in Fallout 4.