The Third Murderer-Louis Hu
Macbeth find two murderer to kill Banquo and his son, but then the third murderer appears, and the appearance of this murderer is actually very strange, and there is no answer in the book that who is the third murderer.
In my opinion, Macbeth is the third murderer. In act 3, scene 2, Lady Macbeth says "What's to be done" and Macbeth answers "Be innocent of the knowledge, dearest chuck, till thou applaud the deed" (Line 49-51) Lady Macbeth keeps asking Macbeth about his plan, but Macbeth doesn't want to tell her this time, but why Macbeth doesn't want to share his plan to her? Lady Macbeth is the closest person, they even kills Duncan together, they should be the best partner. So Macbeth's action is very strange this time. "Come, seeling night, scarf up the tender eye of pitiful day, and with thy bloody and invisible hand, cancel and tear to pieces that great bond which keeps me pale! Light thickens, and the crow makes wing to the rooky wood; good things of day begin to droop and drowse, whiles night's black agents to their preys do rouse. Thou marvell'st at my words: but hold thee still; things bad begun make strong themselves by ill: so, prithee, go with me" (Line 51-61)This is a monolog of Macbeth, he seems very confidence about his plan and he doesn't want anyone else know that, this means his plan is probably very dangerous that he will be one of the murderer, especially he says "go with me" at last, seems like he is saying that to other two murderer. Also, the talking between the third murderer and the other murderers is strange too, the third murderer doesn't talk much when he join with the other murderers, when the first murderer ask him "But who did bid thee join with us " he only answers "Macbeth" (Act 3, scene 3, line 1-2), he is new to this group, it is really strange to not ask them more details about the plan. Overall, because of doubtful points, I think the third murderer is Macbeth.
Comment on another posting:
I disagree with Nikki's point that the third murderer is a random person, because Macbeth at act 3 already becomes truly evil, he doesn't want Banquo's child be the king in the future, so he really wants to kill Banquo and his son. However, Banquo is general in king's army, he should be very strong, so a normal killer is very hard to kill him. So, to make sure they will be killed, it is very possible that Macbeth decides to go with them and becomes the third murderer. There are also some quotation in scene 3 that can show the third murderer is not a random person, for example, he says " Who did strike out the light?" (line 27) but the first murderer answers "Was't not the way". Why does the third murderer knows something that other murderer does not know, and he seems really care about the fled of the son. Therefore, I disagree the third murderer is a random person.