奸

evil design

someone who curries favor with their master while secretly plotting against him

shrewd (dirty) trick

cunning

letter explaining the reasons for cutting down an alleged villain

evil thief

disloyal retainer

wiles and cunning

Chinese traitor (esp. a collaborator with the Japanese)

wicked person

wicked design

villain

cunning and wickedness

killing a villain (with a sword, dagger, etc.)

cunning