A parolee, Blackwell served 12 years in prison for killing another driver while driving drunk. After being released, he started doing menial temporary jobs. The Machine identified him as a Person of Interest and sent Reese to assist him. Reese found him to be harmless and attributed his number coming up to the Machine malfunctioning. Blackwell is later approached by a Samaritan agent, Mona, who tells him he has a lot of potential and recruits him as an asset. He has an IQ of 153.
An assassin, she is hired by The Machine to kill Reese after it identifies him as a threat due to a glitch in its system. She engages Reese in a lengthy firefight, but is eventually disarmed and arrested by him.