Montresor is a borderline psychopath because of all his actions he took throughout the short story to accomplish his ultimate goal which was to end Fortunato's life. Some traits of a psychopath are glib and superficial charm, grandiose (exaggeratedly high) estimation of self, pathological lying from mind disorders. Montresor fits all these traits perfectly just by all of his actions throughout the short story. First of all his superficial charm is shown by convincing all his servants that he will not be returning to the manor until the following day so they would not be there when he returns to do his deed.Second of all he thinks highly of himself and his family name by exacting revenge on the exact person that was insulting him and his family
