Serial Killers, what are they? Criminals, Psychopaths, and Charming? Believe it or not, most serial killers share traits of charm, kindness, and charisma. Some can use these traits in their favor, seducing victims and the public alike. These combined traits mimic their humanity and empathy for other human beings, making them the most dangerous and sinister predators of all. Here are some of the most charming serial killers that we have seen so far.