He has eyes of the indefinite shae of the sea before a storm. He has teeth sharp and pointed as a vampire's and he has a murderer's smile.
He's the vice principal at a high school where the hero Nathaniel Delaney attends in a town called Cheshunt. Mr. Karle is presented as completely evil.
His fiendish schemes, lack of empathy for anyone who does not tow the line, and his remorseless pursuit of the members of the Circle who threaten his plan to control Cheshunt and surrounding areas, show a man without morals or compassion- a monster in human form. He delights in the intimidation and physical abuse carried out on Nathaniel.