Provide evidence showing that Macbeth will do anything to become and remain the King.  

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dule05 eNotes educator| Certified Educator

Macbeth's perilous ambition to become the King will drive him to commit many evil acts which will ultimately lead to his downfall. Once he has the idea of becoming the King solidified in his mind, he does anything he can to make it possible:

  Stars, hide your fires;
  Let not light see my black and deep desires...

Indeed, his "black and deep desires" lead him to commit hideous crimes directly or indirectly. When he kills King Duncan and has Banquo killed, we see that he is more than resolute to make sure that he becomes the King and remains the one for good. The only difference is that, at the beginning of the play, he is victimized by his guilty conscience, while towards the end, he becomes a ruthless murderer, ready to kill anyone who stands in his way:

 I have almost forgot the taste of fears;
 The time has been, my senses would have cool'd
 To hear a night-shriek...

 Direness, familiar to my slaughterous thoughts
 Cannot once start me.
He is not afraid of anything or anyone anymore. The accumulation of the horrific acts he has committed has made him completely numb. He cannot distinguish the good from the bad. And that leads to his inevitable demise.