There is a way, and it's called being Fluce. Friend of the family's character when my parents role-played; elf cyborg. As a magical creature cut off from magic, he went insane. He liked to nuke villages from a couple miles away. Not related to th mission, could have killed them with his bare hands, but he chose to nuke them. The part killed the Four Horsemen of the Apocalypse at one point, he took the credit, and was knighted in England. Later, when the squire came to him and requested help, this is what he said "Are we alone?" "Well, yeah, you're in an alley so it's not like you're out in the open..." "I squish his head!" Had to the party's champion to fight a demon(and for reference, it was an easy demon for him to defeat at that point) at one time, and absolutely refused, unless he got to use what was basically Mjolnir. When he got in trouble for whatever he did, always went running back to Lokan, the party 'leader' (and a powerful vampire). Granted, the dragon was the only good party member, really, and they ended up taking over a hell dimension(at which point Fluce became a demon because Lokan realized how insane he was, killed him, and revived him as a demon), but still the best example of stupid evil I can think of.
Also, it's based on everything. Facial features, body posture, involuntary movements, twitches, tone of voice, physical reactions. Sure, he'll have a hard time reading you. At first. Then he'll start figuring it out, and you'll be an open stone tablet.