Explain the role of witches in Macbeth

Witches indeed play a significant role in Macbeth. They appear at the outset of the play, that enhances the dark and mysterious nature of the play.  The Three Witches are also known as the "Weird Sisters". Throughout the play, the witches act as the predictors. The three witches can also be symbolised as the unconscious mind or evil thoughts of the Macbeth.  

The witches' prophecies are central to the development of the plot. They predict Macbeth's rise to power and eventual downfall. The first set of prophecies includes Macbeth becoming the Thane of Cawdor and then the king. The prophecies spark Macbeth's ambition, making him think about the possibilities of fulfilling his wishes.

The witches often speak in ambiguous language, using paradoxes and riddles. For example, they tell Macbeth, "All hail, Macbeth! Hail to thee, Thane of Glamis! All hail, Macbeth, that shalt be king hereafter!" This ambiguity adds to the sense of mystery and contributes to the theme of deception and treachery.

The witches possess supernatural powers that go beyond mortal understanding. They can predict the future, vanish and reappear at will, and manipulate elements of nature. The supernatural atmosphere they create adds an eerie and haunting dimension to the play.

The witches' influence on Macbeth is a major factor in his tragic downfall. As Macbeth becomes more power-hungry and paranoid, he consults the witches again, who provide him with further prophecies and visions. These prophecies give him a false sense of invincibility and courage.

Lady Macbeth as The Fourth Witch in Macbeth

William Shakespeare's tragedy "Macbeth" introduces us to a trio of witches whose prophecies set forth protagonist's tragic downfall. However, amidst the supernatural aspect of these witches, there is another character whose influence on Macbeth is equally profound – Lady Macbeth.

After reading her husband's letter about the witches' prophecies, she immediately conscious about the power. Her famous soliloquy in Act 1, Scene 5, Come, you spirits That tend on mortal thoughts, unsex me here And fill me from the crown to the toe top-full Of direst cruelty! Make thick my blood…" reflects her desire for supernatural strength and cruelty. This plea to be unsexed conveys her hunger for power .

Lady Macbeth exhibits a cunning and manipulative nature reminiscent of the witches. She employs psychological tactics towards Macbeth into committing regicide. Lady Macbeth's language and actions altogether suggest the striking similitude with the king. In fact she triggers and strengthens all the evil thoughts inside Macbeth. Lady Macbeth's participation in the murder further solidifies her association with the supernatural, making her an extension of the witches' influence.

As the play progresses, Lady Macbeth's psychological state deteriorates due to guilt and remorse. Her sleepwalking scene in Act 5, Scene 1, where she tries to wash imaginary bloodstains from her hands, echoes the witches' appearances within her.  Her descent into madness aligns with the supernatural forces in the play.