Renowned Shakespeare scholar Harold Bloom calls Macbeth
...an uncanny unity of setting, plot, and characters, fused together beyond comparison with any other play of Shakespeare's.
Certainly, Macbeth exhibits an excess of blood and is even referred to as "a tragedy of blood" in its murders and in the imaginations of such as Macbeth and Lady Macbeth. The first bloody murder is that of the former Thane of Cawdor in Act I. In Scene 2, the king, Duncan, and his forces have engaged in battle with the King of Norway and the traitor Macdonwald. Just then, a wounded captain arrives after having saved Malcolm, Duncan's son, from the battlefield. Malcolm, then, has the captain relate what has transpired in the field. The king, then, learns that brave Macbeth wrestled for a time with the traitorous Macdonwald
Disdaining fortune, with his brandished steel,
Which smoked with bloody execution,
Like valor's minion carved out his passage
Till he faced the slave:...
Till he unseamed him from the nave to th'chops,
And fixed his head upon our battlements. (1.2.17-22)
Hearing of this bloody victory, Duncan declares, "O valiant cousin! Worthy gentleman!" And, when he learns that Macbeth and Banquo were not the least dismayed by the fresh attack from Norway, King Duncan then meets with Ross and Angus who report that the Thane of Cawdor "began a dismal conflict" until Macbeth defeated the troops. The king, then, tells Ross,
No more that Thane of Cawdor shall deceive
Our bosom interest: go pronounce his present death,
And with his former title greet Macbeth. (1.2.64-66)
In the meantime, Macbeth and Banquo cross a heath near Forres and encounter three witches, who are stirring a cauldron. When Macbeth addresses them, the first witch greets him, "All hail, Macbeth! Hail to thee, Thane of Cawdor!" (1.3.50). Later on, Macbeth encounters Ross and learns that he has, in fact, been made Thane of Cawdor. He wonders then, too, that having correctly predicted his earning the title of Thane of Cawdor, if the witches were also correct in their predicting that he also would be king.