Chrono's Good-Luck Piece
At a specific point in the novel, Chrono (Constant's son via Beatrice Rumfoord, conceived on Mars) picks up a piece of scrap metal he discovers next to him as a sort of "good-luck piece." As Winston Niles Rumfoord told Constant earlier in the novel, this piece is incredibly important for the fate of humanity, a warning that seemed nonsensical to Constant at the time. It is revealed, however, that this "good-luck piece" is actually the part manufactured by humanity in order to fix Salo's spaceship, and when Chrono brings it to Titan, it accidentally enables the repair of Salo's ship, which was the entire point of the development of humanity. This piece of scrap metal, therefore, comes to represent the random, arbitrary nature of meaning in this harsh, unfeeling universe (in Vonnegut's view), as well as the sole source of importance for the human race.
Winston Niles Rumfoord
Having flown his personal spacecraft into a chrono-synclastic infundibulum, Winston Niles Rumfoord is now a wave-like phenomenon that spirals between planets in the vastness of space. He now has the ability to see the future, and he is the primary mover behind all of the novel's events, giving Constant prophecies and manipulating humans into creating the Martian invasion of Earth, all in order to create a piece of scrap metal for Chrono to pick up. Rumfoord is a parody of God, moving all the strings to fit his arbitrary will, and is therefore representative of Vonnegut's twisted view of religion.
Boaz
Boaz is one of the undercover leaders of the Martian invasion of Earth, pretending to be just another mindless soldier while actually possessing the box that controls the others. Despite his position, however, Boaz desires to desert the army, living the dream life on Earth, and in order to achieve his dreams, he befriends Unk (Constant), whom he believes to have been a successful man on Earth. Boaz is a symbol of humanity's selfish and escapist desires, as he deserts the army despite his duties in search of his own fleeting happiness. He eventually finds satisfaction on Mercury, however, hinting that there can be some feeling of completion in this crazy universe.
The Sirens of Titan
In order to try to convince Constant to go to Titan, Rumfoord claims that the women there are infinitely more beautiful than the women on Earth, showing him a picture of three stunning, scantily clad women of different colors (the Sirens of Titan). When Malachi arrives at Titan, though, he finds it deserted of all humans; these "Sirens" are nothing more than statues at the bottom of a lake. The Sirens of Titan therefore symbolize the illusory nature of perception, as well as the empty promises of Rumfoord, the novel's God-figure.
The Church of God the Utterly Indifferent
Rumfoord's new created religion, the Church of God the Utterly Indifferent, is a symbolic parody of Christianity. The implicit argument in the religion's title is that, if God really exists, he clearly doesn't care about what's happening on Earth, as he hasn't done anything to stop the horrors of life. This new religion explicitly acknowledges this fact, espousing the idea of a God who is simply and utterly indifferent to the plight of humanity. This makeshift religion is a symbol of Vonnegut's twisted perception of organized religion, a satire so biting it can make a reader somewhat nauseous.
