Duncan's guards are sacrificed after Duncan is murdered. When Macbeth is on his way to kill Duncan, he passes the sleeping guards and thinks he hears “Sleep no more! Macbeth hath /murdered sleep. This causes Macbeth to leave Duncan's murder scene with the bloody daggers. This forces Lady Macbeth to return the daggers and put them by Duncan's body. Then, when Macduff announces the king has been murdered, Macbeth says he saw the body of Duncan and became so angry that he killed the guards. He blames the guards for the murder of the king and says they had blood all over them and the daggers in their hands. The poor guards have no chance to defend themselves and also are not left alive to tell anything they know about Duncan's death.