The Purple Moon Religion (紫月教団, Shigetsu Kyōdan) is the sole form of worship on Purple Moon Island, being compulsory for all 3,000 of its residents. The religion was established by a small group of ninja who first settled the island and came to revere nature. As a mark of their faith, all members have their ears punctured with five holes, giving the resemblance of a constellation visible in the night's sky above the island. Purple clothing is also commonly worn by the religion's followers.
The Purple Moon Religion worships nature above all else, believing that Mother Nature is responsible for protecting them. For this reason they reject the influence that the Mizukage has over the neighbouring Land of Water, and as such they have little contact with that or any other country. In fact, the Purple Moon Religion disapproves of most forms of mass transit, effectively isolating them from the rest of the world and thus rendering their religion unknown to foreigners.
By virtue of the fact that they worship nature, the Purple Moon Religion also reveres science, and therefore in combat prefers such weapons as conventional bombs or firearms. Because the religion was first established by ninja, ninjutsu is also practised - Lightning Release seeming to be the most common form - but even its strongest members are no more talented than chūnin. Despite this relative lack of skill, members are merciless in combat, pursuing their targets no matter how injured or outmatched they may be. If they are at risk of being captured, members will not hesitate to take their own lives so that they can't be made to betray the Purple Moon Religion; if a member is knocked out before they can kill themselves, it falls to their allies to kill them instead.
In the years after the Fourth Shinobi World War, travelling across long distances becomes much easier thanks to technological innovations of Konohagakure and the wider Land of Fire. This causes a small extremist faction to form within the Purple Moon Religion that is bent on destroying Konoha, the hope being that without Konoha there will be a halt to the continuing availability of free travel. Most of these extremists attempt to destroy Konoha with terrorist bombings across the Land of Fire. One extremist, Lily Himeno, tries instead to simply destabilise Konoha as a spy, achieving similar results without civilian casualties. All the extremists are either captured or take their own lives fighting Konoha's ninja. Lily is subsequently recruited by the Seventh Hokage to liaise with rest of the Purple Moon Religion and convince them to update with the times.