Game concept
Realm Priest
The game also links it as Realm Priests, Realm Priest's.
From the game's encyclopedia
A Realm Priest is a Councillor in charge of religious and spiritual affairs in Faiths with the Theocratic Doctrine.
Unlike their Lay Clergy equivalent (Court Chaplains), Realm Priests automatically Lease all Temple Holdings in a Ruler's Domain, and also receive a portion of Taxes and Levies from Vassal Realm Priests.
Realm Priests provide their Liege with Levies and Taxes if they have a positive Opinion of them. The higher the Opinion of their Liege, the more they will provide.
Realm Priests with a low Opinion of their Liege will not provide them with any Taxes or Levies, and might cause problems.
The game's text for patch 1.20.1.2. Words in blue are entries of the encyclopedia: hover one to read it, as in the game.
Realm Priest is an entry of Crusader Kings III's in-game encyclopedia. The game explains it: "A Realm Priest is a Councillor in charge of religious and spiritual affairs in Faiths with the Theocratic Doctrine." It is part of Councillor. The game also links it as Realm Priests and Realm Priest's. Patch 1.20.1.2, from game/common/game_concepts/00_game_concepts.txt and game/localization/english/game_concepts_l_english.yml.
Source: game/common/game_concepts/00_game_concepts.txt, game/localization/english/game_concepts_l_english.yml and the English localisation, Crusader Kings III 1.20.1.2.