from the individual who as a child was "fascinated by fire" and
actually started fires, tortured small animals then graduated to a
sadistic serial killer of their fellow human, do any of these terms
describe someone who is basically bereft of a conscience or failed to
physiologically develop whatever part of the brain that provides the
ability to empathize or feel guilt when it would be appropriate? That's
the person I'd like to understand better.
To that end, here is short "favorites" list (mine) of links that provide different perspectives on the subject: