Christianity
Christianity survives in the Fifth World, though it has changed greatly since the collapse of civilization, just as it changed in its history from a persecuted cult to the state religion of the Roman Empire, through the Middle Ages and the Reformation, and through its history in the last centuries of civilization. While a twenty-first century Christian might not recognize twenty-fifth century Christianity, he likely wouldn’t recognize much of seventeenth century Christianity, either.
#Biblical interpretation
Some families prize the preservation of the Bible, even preserving the knowledge to read and write so that they can copy and read the Bible. Others have select members of the family who memorize the scriptures, word for word, so that they can pass it down from generation to generation. Most, however, seem content to simply absorb Bible stories and passages into the family’s oral tradition.
Fifth World Christians often interpret the Fall as the story of how civilization arose, pointing to how God explicitly cursed Adam with agriculture. They point to God calling Abraham out of the only civilization in the world at that time, and how he tried to convince the Israelites not to establish a monarchy like their neighbors. They find a common thread in Christ's teachings of opposition to civilization, and often see Christ as either a patron of wizards or a wizard himself. Sometimes they even interpret the crucifixion itself as some sort of magical ritual of cosmic importance.
They often associate the collapse of civilization with Christ's Second Coming. As God created Adam and Eve in the Garden of Eden as hunter-gatherers, the end of civilization returned humanity to its original Edenic state — or at the very least to a primordial, worldwide garden.
#Roman Catholic Church
Living amidst the ruins of the Vatican you will find a family that calls itself the Curia. Among them you will find the pope, who can recite the line of his predecessors back to Saint Peter himself. Across the world, you fill find families that still consider themselves Catholics. Many of them tell stories of when the cardinals grew wings and flew away as the birds that bear the same name, with varying degrees of sincerity.
The Catholic Church in the Fifth World does not have nearly the cohesion it did in centuries past. It takes too much effort to travel, and no one has the power to force an “errant” parish to do things differently if they don’t want to. The old hierarchies have, of necessity, given way to a voluntary association of families across the world.
The Jesuits have survived, as well. In the Fifth World they function as couriers and messengers who allow the far-flung Church to retain any sort of communication at all. They bring messages between Catholic families, and from them to the pope, as well as messages from the pope to the faithful. They call themselves “missionaries,” focusing on their mission of keeping the Body of Christ connected, largely failing to even recognize that the word used to mean converting people, much less actually doing so.