What major role does Lady Macbeth have to the murder of King Duncan in Macbeth?
In a sense, Lady Macbeth is responsible for Duncan's death. In fact, she admits that she would have killed him herself had he not resembled her father sleeping. Repeatedly, Lady Macbeth challenges Macbeth's manhood when he has second thoughts about murdering Duncan. She uses manipulation to convince him that the murder of Duncan must occur.
Lady Macbeth pushes her husband into kiliing Duncan. After, the murder, she pretends to be happy and content. However, that all changes for the worse. She begins to lose her mind. She cannot wash the bloodstains from her hands.
Ultimately, Lady Macbeth takes her own life for she cannot deal with the guilt of forcing her husband to murder Duncan. Had she not been so convincing, one wonders if Macbeth would have actually gone through with his plans to murder Duncan.
She encourages Macbeth to kill Duncan. As noted in the previous answer, she states she would have killed Duncan herself if he did not look like her father.
Macbeth also brings the knives back after the killing and Lady Macbeth brings them back to the guards who have been drugged.
lady macbeth told her husband to kill king duncan for thet want the thron and she was also telling him that he wasnt a man and so he start to believe it was true so she gave him a act of influence to the husband she also was the one who put the daggers in the guards hand and wipe the blood on there faces and drunk there and also blamed the guards