Who does Macbeth murder after he murders Duncan?
After he murders Duncan, Macbeth arranges for the murders of Banquo and Fleance, although Fleance escapes. Macbeth is angry that the Weird Sisters told Banquo he would father a line of kings because Macbeth has already defiled his own mind and burdened his conscience with the murder of Duncan, and now feels he must kill Banquo and his son. Macbeth says that he has done all this "To make them kings, the seeds of Banquo kings," and this is unacceptable to him (III.1.75). Macbeth hires three murderers to accost Banquo and Fleance on the road, and they murder Banquo there.
After the murder of Fleance, the next people Macbeth murders are the wife, children, and servants of Macduff, the Thane of Fife. Macbeth learns Macduff has fled to England in order to appeal to Duncan's son Malcolm. To punish this disloyal thane, Macbeth says that he will "Seize upon Fife, give to th' edge o' th' sword / His wife, his babes, and all unfortunate souls / That trace him in his line" (IV.1.171-173). Macbeth vows that, as soon as he conceives of an action, he will perform it. He will no longer weigh his options or coolly consider them, as this delay is what enabled Macduff to escape him.