“True sociopaths lack self control and end up killing folks until they are caught.”
As I recall from the book few sosiopaths actually end up killing, not that they would find it reprehensible but only that it is not necessary to acheive their goals or are smart enough not to cross that line unless they believe it to be necessary. They are dangerous and many of them do kill.
I was making my own moral ranking of personally disorders. Some occupations require a little properly channeled OCD (call it perseverance) to excel.
A Narcissist would not be a mass murderer, but I would rank them right above murdering sociopaths at the bottom of an ethical scale.