A villain can kill anyone, even another villain, because by definition, a villain is a villainous person capable of any villainous act including the killing of a friendly villain.
007's License to Kill means that he is an assassin. He would kill the villain.
The Joker.
The joker
he was beast! oooh kill em hero!
Joker
The Jocker
He was formerly the demon Keldor from another dimension, hit by acid rebounding off randors shield, he became the skeltal villain Skeletor
Not me personally, Freddy is my home boy ^_~But as a horror villain yes, Freddy does kill people.
Cortes was not a hero or a villain, he was both. Cortes killed alot of people on his road to greatness but if he did not kill the word would not be the same
villein
You could try 'villain'
He feels that by killing them, he won't be any better than a villain himself. He also feels that it is wrong to kill.