Shelbie, aka S3-83, aka Breezie, is a deep-cover Gen. III synth operating in the Commonwealth. Sent by the SRB to monitor and report on the Railroad, she would successfully manage to make contact and infiltrate the group, though would have doubts and turn on her masters in self-preservation after the attack on the Switchboard.
Shelbie was "born" in 2283 in the Institute, and was put on work detail, where she showed a gregarious personality, causing the other synths to open up to her. This would be noticed by those in the SRB, and she would be taken for infiltration training. She would be groomed and trained for three months before being told her assignment; to infiltrate and operate as a deep cover informant on The Railroad. She was transported to the Commonwealth, where she would manage to make it to Diamond City.
She would stay here for two months to build her cover and gather intelligence, before moving to Goodneighbor in November. This would prove a dangerous period for Shelbie, as nothing in her training had prepared for the violence and unpredictability in the settlement. She would manage to get by due to her ability to charm, social use of Med-x, and pipe-pistol. She would spend four months before being approached by a Railroad agent.
Shelbie managed to impress the agent and over a series of meeting would be accepted into the Railroad. She would be frustrated to find out that she would be at Stanwix safehouse, a remote outpost with only a radio to headquarters. She would still dutifully report her partial success to her Institute masters, who told her to carry on the guise of a Railroad agent, but to inform them of any synth that came through.
She would carry this out for the next two years, making weekly reports about the station's activities and handing them off to the runner synth whenever it arrived. The runner would arrive less and less frequently by 2285 however, something that quietly worried her. This unease would be compounded by the station briefly going to lockdown as reports of a courser nearby made their way to HQ. Fear would gnaw at her mind during the entire period, mainly that of being recalled and mind-wiped.
She would make up her mind to give the Railroad a chance,having been treated kindly by all the members she met. Shelbie would file vague or false reports after this, to which the SRB either didn't notice, or didn't care. She be surprised in 2287 when the station chief announced the raid on the Switchboard, and that all stations were to remain dark. She was initially happy, but then doubt crept into her mind. She began to worry about being mind wiped, or destroyed, and would destroy and move her safehouses. After two months with no word from either the Institute or Railroad HQ, Shelbie figured she was on her own, and decided the railroad was her best option for survival.
When a Synth did manage to contact her as she was at an old safehouse, she destroyed it and ran, laughing as she did so. She has been a loyal railroad agent since then, and has frustrated several operations by the Institute.
Shelbie posses a small collection of weapon, as demanded as her role, though she prefers an Automatic Radium rifle acquired from the Children of the Atom. She commonly wears a ratty skirt, though does own leather armor for combat.
Despite her outward jovial persona, Shelbie is frequently wracked with anxiety and paranoia due to the nature of her deployment and her subsequent betrayal. She is constantly worried about being killed, both by those in the Railroad who discover her origin, or by her vengeful former masters. She copes by taking Med-x, a habit that has drawn concern from the others in the station before. Alone in one of her safehouses is the only time she is truly herself with her guard down, as she tries to determine which identity is actually her.