The Luskentryan Church is an organization shrouded in mystery. Its founder, Salvador, does very little to answer questions about its history. Salvador claims to be a conduit to God, in the tradition of Ezekiel, Mohammed and Christ. (He claims all previous messiahs in all religions were conduits like himself, and not saviors.)
How the church managed to survive into the post Collapse world is simple; they secured their own cloning technology. On Luskentyre Plateau, the church maintains a building innocuously called a creche, but which is really an advanced genetics and cloning facility. Naturally, how a low technology farming community maintains such a complex pre Collapse jewel is yet another question that Salvador refuses to answer.
It is possible to gain the favor of the Church. They are beset on all sides by hordes of Rock Leeches. Any stalwart adventurer who kills a rock leech will gain some respect in the eyes of the church. Indeed, if one kills enough of them, one is offered membership in the church, and access to their armormaking secrets. Leech-hide armor is a highly sought item, so quite a few people have taken the church up on it's hospitality by killing scores of Rock Leeches.