In William Shakespeare's play Macbeth, the title character is a killer. Through the course of the play, he kills five different people or groups of people, one in each act. These are, respectively, Macdonwald, Duncan, Banquo, Macduff's family, and Young Siward. These five killings are different. In the beginning, Macbeth kills for his king. He then suffers a fall from grace before finally becoming a noble figure again in the end. But more interesting than this process is the way in which Shakespeare shows us the changes in Macbeth's character. Shakespeare uses the killings as a sort of "barometer" to illustrate these changes.
Before the play begins, Macbeth's Scotland and Norway fight a war. In this war, Macbeth is a hero, admired for his courage and strength:
But all's too weak;
For brave Macbeth (well he deserves that name)
Disdaining Fortune, with his brandished steel,
Which smoked like bloody execution,
Like valor's minion, carved out his passage
Till he faced the slave;
Which ne'er shook hands, nor bade farewell to him
Till he unseamed him from the nave to th' chops
And fixed his head upon our battlements.
The killing that the Captain describes here is Macbeth's most heroic killing. The Captain admires him for his remarkable bravery. The other members of the Scottish court continue in praising him. Macbeth's motive for killing here is, unlike all his later murders, not a personal reason. It is a selfless, courageous, heroic deed that is thought to be able to save Scotland from utter destruction. Shakespeare uses this killing to introduce the audience to Macbeth. Here, we see Macbeth as a hero. This is possibly the most potent way in which Shakespeare could introduce Macbeth's heroism to us. What could be more heroic than killing for one's king?