The cast in a mystery novel often includes the detective, who is the central figure in solving the mystery. For example, Sherlock Holmes is a very famous detective character. Then there are usually suspects, each with their own motives and alibis. And there might be sidekicks to the detective, like Dr. Watson for Holmes, who assist in the investigation. There are also victims, whose situations set off the whole mystery - whether they are murdered or have something valuable missing.
The cast of characters in a mystery novel is quite diverse. The detective is the one who drives the story forward. They use their deductive reasoning skills to figure out what happened. The suspects add suspense. They may lie or mislead the detective. Some mystery novels also have a love interest for the detective, which can add another layer of complexity to the story. And let's not forget the villains. They are the ones behind the mystery, often with a devious plan.