What does the irony of the "beast" (parachutist) still being "alive" while Simon the supposed "beast" was killed effectively show?

The most important event of Chapter Nine is the murder of Simon by Jack's tribe. They are in a trance-like state from their ritual dancing, although this does not excuse them. The murder continues the parallel between Simon and Jesus established in the previous chapter by depicting the murder as a sacrifice, akin to Christ's murder on the cross. Like Jesus, who was the sole bearer of knowledge of God's will, it is Simon who alone possesses the truth about the beast. Also like Christ's, Simon's tragedy is governed by the fact that he is misunderstood or disbelieved by those around him. For example, the other boys believe Simon is crazy, yet he is the only boy to discover the truth about the supposed beast. This irony is compounded when Jack's hunters mistake Simon for the beast himself. His murder represents the culmination of the violent tendencies prevalent among Jack's band of hunters, who finally move from brutality against animals to brutality against each other. The change is subtle: they murder Simon out of instinct, descending on him before they realize that he proves no danger to them. Nevertheless, this is yet another line that the boys cross on their devolution into inhuman savagery and another step toward engaging in complete and premeditated violence against one another. Simon's murder reveals the essential brutality of the human spirit. On both metaphoric and structural levels, Golding casts Simon as a martyr, a figure whose death is instructive at least to the reader.

The parallels between Simon and Christ continue even after Simon is dead. We may note not only the religious subtext of the chapter's final image, but the distinctly pessimistic tone of this subtext. The storm simultaneously removes the parachutist's and Simon's bodies from the island. Yet, while the parachutist appears to ascend on the winds, Simon is dragged under the tide. The parachutist, who represents both the war that caused the events that brought the children to the island (he is a soldier) and, in a more general sense, the evil that is present in the human psyche (he resembles a fallen angel, a common figure for Satan), is lifted into the sky, while Simon, a Christ-like figure, appears to descend beneath the surface of the earth. The image, therefore, reverses the traditional story, with Satan rising to the heavens and Christ descending to the underworld. The implication is that the ideal order of good and evil has been reversed on the island. Evil has triumphed, a suggestion that mirrors Jack's rise to power and foreshadows the even more tragic events to come. Still, a vestige of optimism remains: Simon's body, as it is carried out to sea, is surrounded by some small glowing fish, who function as a kind of living halo. They do not necessarily want to eat the body; perhaps they are figuratively honoring it. The implication is that the truth of Simon's message, and the injustice of his death, will be recognized in time, as is the case with martyred prophets and saints.