Unethical conduct is actually the conduct of destruction and fear; lies are told because one is afraid of the consequences should one tell the truth; thus, the liar is inevitably a coward, the coward is inevitably a liar.
He was a volatile mixture of confidence and vulnerability. He could deliver extended monologues on professional matters, then promptly stop in his tracks to peer inquisitively into his guest's eyes for signs of boredom or mockery, being intelligent enough to be unable fully to believe in his own claims to significance. He might, in a past life, have been a particularly canny and sharp-tongued royal advisor.