The second book in Jenna Black’s Morgan Kingsley series is titled “The Devil You Know.” Exorcist Morgan Kingsley’s aura is stronger than her demon’s, despite the demon’s ability to make her body act absurdly. She recently learned the startling fact that all of her preconceived notions about her identity and past might have been false. Morgan, a major character in an unstable universe, must contend with The Hunter, a psychopathic demon gone rogue.