21. Col. Hans Landa in Inglourious Basterds
This one is tricky. Landa is a Nazi. He is the Jew Hunter. He is a murderer. Landa however is serving in one of the most feared armies in history. His hesitation or his compassion in the Nazi administration would lead to certain death. He even tries his hand at heroics by offering to end the war killing Hitler and the entire Nazi command for the Allies. Hes as tired of the Germans as the rest of the world and plots to blow Hitler to hell albeit at a terrible cost to his forehead.
20. Loki in Thor
As much as I loved last years Thor I did feel there was a lack of a menacing villain. Loki isnt really revealed to be the villain until well into the second act and even then, he is not inherently evil. He feels betrayed and unloved by his adopted family. He is guilty of some sibling jealousy which we have all felt at some stage in life. Loki deals with some shocking discoveries (he is in fact an adopted Frost baby) and his arrogant brother Thor. Its a very Shakespearean plot but the bards characters were a lot more ruthless and Machiavellian than the God of mischief. Loki does amp up the bad in The Avengers even killing beloved Agent Coulson but in Thor its all very teenage angst stuff.