Sharon Fulton is a serial killer by proxy and member of The Blacklist.
Sharon Fulton is a FBI psychiatrist who evaluates agents to determine if they are fit for duty. Sharon has paid for the counseling of the families of the victims of serial killers who were never caught. Those families' grief and pain along with the lack of justice for their loved ones broke Sharon, making her decide to take action on her own. Using her knowledge and skills in forensic psychiatry and criminology, Fulton would identify and track serial killers who escaped justice and kill them in the same way they killed their victims. However, she did not do the killing herself but enlisted the help of other federal agents who, like her, were disillusioned with the justice system. After Elizabeth Keen shot and killed Attorney General Tom Connolly for being a traitor, Fulton became interested in her and decided to recruit her. Her interest in Keen increased after it was revealed that Keen was Raymond Reddington's daughter.
In her counseling sessions with Keen, Fulton seems determined to get Keen to explore her darker emotions. Fulton begins asking Keen about a cold case from her past, which surprises Keen as that case is classified. Later, trying to track the Capricorn Killer's copycat, Keen (with Reddington's help) manages to read Fulton's files on her past patients, which are sealed. Keen gets Fulton to confirm Keen's theory that the copycat Capricorn Killer is one of Fulton's past patients, Anthony Eliot Hollis. Keen directs the Post Office to track down Hollis in the woods, where Keen is captured by Hollis and walked through the woods to a cabin. Fulton appears there, revealing to Keen that she has been tracking, solving, and killing cold case serial killers in their own style for years, enlisting people like Hollis (a former patient) to help. Fulton tells Keen that if she joins Fulton's operation, she will clear Keen for full active Agency duty. Fulton and Hollis attempt to get Keen to murder the tracked-down committer of an old child murder case; before she can, Hollis is shot by FBI agents and Fulton flees. Keen tracks Fulton down in the woods, but lets her go. Later on, Fulton appears at the Post Office, announcing that she has cleared Keen for active duty, and Keen is reinstated.