This is when a tribe, a caste, an ethnic group, or even an entire species is associated with the clerical duties of a religion. The reasons can range from simple tradition, to genetic and/or socio-cultural predisposition for religious activities, to a supernatural pact between that group and its respective deities.
Can be a subtrope to Planet of Hats.
- In The Belgariad, the Mad God Torak divided his Angarak followers into four tribes: the Thull serfs, Nadrak merchants, and Murgo warriors each have their own countries in the West, while the Grolim priests run his Religion of Evil in all of them. Even other Angaraks widely fear them, since they have a lot of discretionary power in conducting the religion's large-scale Human Sacrifice.
- In Courtship Rite a Lost Colony is divided up into economically (and eugenically) specialized "clans", with tribes of priests such as the protagonists' Kaiel clan and the rival Mnankrei, ruling.
- In Everworld, the characters note that all male Hetwans are warrior-priests dedicated to their god, Ka Anor, while females seemingly only exist to mate and die. As a result, their whole society is geared toward conquering Everworld and capturing gods for Ka Anor to eat.
- In John Carter of Mars, the Holy Therns are an society of White Martians self-appointed as high priests of Issus, and responsible for luring all other Barsoomian races into their domain so they can be enslaved. Subverted when its revealed the Therns are manipulated by another race entirely controlled directly by Issus, who commands their men to prey on their females.
- The Han Solo Trilogy: All clergy in the One and the All faith are males of the t'landa Til species. In fact, many Pilgrims don't even seem to know their species' name, and just call them "Priests". This is because only males of their kind are capable of the Exultation the faith is built around-it's really a mating call to t'landa Til females that also has a very pleasurable effect on other beings too, with the whole religion being a scam.
- Halo has the San'Shyuum, also known as the Prophets. Given that the Covenant they are a part of is a Church Militant, this makes them the leaders by default.
- According to The Legend of Zelda: Breath of the Wild, the Zora race are associated with religiousity. One Hylian character in Rito Village explicitly labels them a "spiritual" people compared to others. The Tarrey Town sidequest tasks you with finding a Zora whose name ends in "-son" who can officiate a wedding because of this, and the fact that the Zora you do bring along was in fact a retired priest is considered by the quest-giver to be more of an unexpected bonus than an absolute requirement. And while it's not said as explicitly as with the Zora, the Sheikah are also depicted as having a very clergy-oriented culture based in large part on their devotion to Hylia and all their self-mummified monks waiting in the Shrines.
- The Shrouded Isle's sole village is a cult- as in, there's no distinction between villagers and cultists. Everyone has duties to the cult, everyone belongs to it, and the leader's political advisors must also carry out spiritual responsibilities such as penitence and book-burning. Even the village's children are tortured in accordance with Chernobog's will- although they are not told of the Human Sacrifice that occurs every season.
- Warhammer Fantasy: The subspecies of Lizardmen are devoted to various duties: Skinks are bureaucrats, skirmishers and priests, Saurus are warriors, Kroxigor are Dumb Muscle, and the Slann are extremely powerful wizards.
- Warhammer 40K: Tau society is divided into five Castes, each with a different function: the Earth Caste are engineers and scientists, the Air Caste are pilots, the Water Caste are diplomats, the Fire Caste are warriors, and the Ethereals lead the rest, possibly using mind control.
- In Orthodox and Conservative Judaism, special note is given to the Kohanim (descendants of the priests, that is, of Aaron) and Levi'im or Levites (descendants of the tribe of Levi, who assisted them). "Cohen" means priest, and people who bear this last name (very common in Ashkenazim) or Levi trace descent from these.
- Beyond that, the Bible refers to Israel as "a kingdom of priests and a holy nation." The general idea is that one day everyone will worship God, with the Jewish people as the priesthood of humanity.
- The Brahmin caste in Hinduism.