Dr. Alex Cross : An African-American forensic psychologist as well as a detective, described as good-looking and well-built. He is often referred to as "Doctor Detective." Despite being very dedicated to his job, he manages to be a devoted father to his two children. He is the uncle of Naomi Cross, one of the Casanova's victims, which is the reason why he travels south to help in the investigation.
Dr. Kate McTiernan : A young physician who is captured by Casanova as part of his "harem", but manages to escape from his underground hiding place thanks to her martial arts skills. After recovering physically, she joins Cross on the hunt for her abductor, and starts to develop a close relationship with him.
Casanova : A serial killer from North Carolina who "collects" beautiful, exceptional young women whom he holds in an underground "harem", raping and eventually murdering them. He bonded with The Gentleman Caller years ago and they murdered women together for some time.
The Gentleman Caller : The other serial killer in the story, a much more brutal and direct murderer who likes to cut off bodyparts and keep them as trophies. He murdered a young couple on a lake in the early 80s, and was soon discovered by Casanova, with whom he formed a unique bond.