Macbeth is not solely culpable however. It was Lady Macbeth who convinced him to eliminate the king so that he could seize the throne. Early in the play she resolves to ‘‘pour my spirits in thine [Macbeth’s] ear’’ therefore her so-called spirits can be blamed for overwhelming Macbeth. It can be said that Lady Macbeth has more liability for Duncan’s murder than Macbeth himself as she used her position as his wife to induce her husband to the sin. She knew the ‘‘adoration’’ and ‘‘dearest love’’ Macbeth had for her and threatens this by questioning his manliness and devotion to her. This is her wicked tactic to manipulate Macbeth into going ahead with the killing. Lady Macbeth is also directly a cause for Macbeth’s actions. She forms the details of the plan to kill Duncan, and orders him throughout the play, such as ‘‘give me the daggers’’ and ‘‘leave all the rest to me’’, both very demanding. It appears to me that without Lady Macbeth’s ‘‘ direst cruelty’’ Macbeth would not have had the willpower to carry out the task. Perhaps he is merely a tool, manipulated by Lady Macbeth to achieve her goal to be queen.
It could also be argued that the witches, out of spite, spurred on by pure evil, set up the whole thing for their own pleasure. For the prophecy to become reality, itself is essential. Because, if Macbeth hadn’t been informed that he would be king he would never have considered regicide. Macbeth proves this when he questions the witches, ‘‘to be King stands not within the prospect of belief’’ clearly surprised by their prophecy. It is undisputable that the ‘‘three sisters’’ are malevolent and supernatural. Shakespeare uses language to portray this – the witches do not speak in blank verse like all the noble characters, they also rhyme words often making their conversations seem like incantations: ‘‘when the hurly-burly’s done, when the battle’s lost and won. That will be ere the set of sun.’’ It is apparent that compelling Macbeth to murder could be some kind of game to the witches. It seems to be a regular outing for them, when one jovially asks ‘‘when shall we three meet again?’’ It is sensible to put the witches at fault because they act with no guilt or remorse because they do not know right from wrong as is evident by the phrase ‘‘fair is foul, and foul is fair’’.
The final culprit for Duncan’s death is Duncan himself. His own blind trust in the members of his court even though one of them had all ready betrayed him is what doomed him. Ironically when Duncan refers to the original Thane of Cawdor after he was told of his execution he describes as ‘‘a gentleman on whom I built an absolute trust”, he in my opinion is unconsciously referring to the new Thane of Cawdor as well, as if Macbeth inherited the traits of his predecessor with the title. The crucial mistake Duncan made was to have faith in a person who shares all the attributes of the traitor. This fault was fatal as it proved to be at the time of his demise. He was overconfident with his friends, when secretly they were his enemies and should have been more wary of the treason. Duncan is far too kind and welcoming with potential adversaries and as a result cannot see the deceit in them: the person who plans his death and latter cover-up is to him simply ‘’our honoured hostess’’. He seems incapable of perceiving evil.
To conclude the discussion, I would answer that there is no individual culprit for the death of Duncan, because each contribute importantly: The witches commence the reaction that starts the series of events leading to murder; Lady Macbeth reassures Macbeth, pressures him into the sin, and conceals the evidence by ‘‘[smearing] the sleepy grooms with blood’’; Macbeth has the ambition, and is too weak to resist corruption and not be persuaded into proceeding with Lady Macbeth’s plans; and Duncan is foolishly naïve and fails to notice a plot right under his nose, even bringing himself to the scene of the crime with only two guards. Without either of the factions the death would not occur, therefore they are equally responsible.