Macbeth killed King Duncan and even though Macbeth did does not mean he is responsible. In my opinion is that Macbeth and Lady Macbeth are both responsible fore the murder of duncan. Macbeth said he didn't want to do it but Lady Macbeth questioned his manhood. Macbeth says "If we should fail". In this quote he is already starting to rethink it and that he is not sure if it is a good idea. Lady Macbeth is responsible because she knew what waas going to happen. She knew why they were doing. She was the mastermind behind the idea, that