What if Banquo does have decedents that are kings?
Will not be beaten until Birnam wood comes to Dunsinane.
Will never be defeated by anyone of women born.
Macbeth is crowned King of Scotland. The witches' prophecy makes Macbeth believe that he must kill Banquo and his son Fleance, because Banquo's descendants might become kings of Scotland Macbeth orders two hechmen to carry out the job. However, Fleance escapes and is also concerned that the witches' predictions could some true.
Macbeth has a banquet and sets a place for Banquo, knowing full well that he is dead. However, he sees the gory ghost of Banquo in the seat left for him and Macbeth shouts in horror at the ghost. His guests suspect that he has a guilty conscience.
Macbeth goes back to the witches. They show him apparitions. the first a head with armour on (to represent Macbeth's own severed head), the second is a bloody child (likely to be Macduff after he was ripped from his mother's womb) and the third is a crowned child with a tree in its hand (to represent Malcolm and the Birnam Wood).
Macduff is sure that Macbeth murdered Duncan and decides to join Malcolm in England. He raises an army of 10,000 Englishmen in order to kill Macbeth and reclaim the throne. In rage that Macduff fled to England, he orders his henchmen to kill Macduff's wife and children. This changes the views of some of his followers, who desert him.
Lady Macbeth has gone mad and talks in her sleep about washing blood from her hands. A messenger tells the king that the wood is on its way to Dunsinane and Macbeth is worried.
When the army arrives at the castle, Macbeth recklessly attacks and kills many men because he believes that no one can kill him. However, Macduff tells Macbeth that he was not born of woman because his own mother gave birth to him by caesarean and they start to fight. Macduff kills Macbeth and his head is displayed for everyone to see.