Charles Cullen
Charles Cullen is the protagonist and an American nurse who killed over three hundred patients during his practice in various hospitals in the United States of America. Charles Cullen was born in 1960, but unfortunately, his father died when he was only six months old. At 17, Cullen's mother died in a tragic accident, which left him traumatized. Cullen was stigmatized and bullied for most of his life, and he grew up to become a bitter man. At last, Cullen was caught in the act of his criminal activities while trying to kill his patients, and he got charged before the court of law.
Adrianne
Adrianne is Cullen's wife; at first, she does not know she is married to a murderer. However, later Adrianne started noting the weirder character of her husband because he was abusive to his daughter and the family dog. When Adrianne finally discovers her husband is a murderer, she leaves him to seek peace of mind.
Tim Braun
Tim Braun is a lead investigator in the case of Cullen, and he tries to gather evidence to ensure Cullen was put behind bars. However, Braun's efforts were often frustrated due to the unwillingness of the hospitals to share the actual evidence that could be used against Cullen.
Danny Baldwin
Danny Baldwin is another investigator working alongside Braun to uncover the truth about Cullen’s allegations. Baldwin and his colleagues are under pressure to deliver, but the task is not easy because getting the right evidence proves tricky, but they are determined to achieve their objectives.
Gall
Gall is one of the patients killed by Charles Cullen during his mission to murder his clients. After the death of Gall, a pharmacy employee reported his death to the Centre of Poison Control authorities, but nothing was done because they did not involve the police in time.
Cullen’s parents
Cullen's parents die in unclear circumstances, leaving him depressed. For instance, Cullen's father dies when he is six months old, while his mother dies when he is 17. The death of Cullen's parents leaves him unstable, and he finds himself the only male among females in every aspect of his life. Therefore, Cullen starts hating women and slowly starts killing them in his profession.
Amy Loughren
Amy Loughren is a critical character because she is the first person to discover Cullen's madness and inhumane activities in Somerset. While revisiting hospital records, Amy discovers that there are intended cases of overdose, and they were all conducted by Cullen. Consequently, Amy discovered that Cullen was a murderer, and she reported the case.
