High Priest

A character (or several) that leads the religious group they belong to. They can be either good or evil, depending on whether the religion in question is a Saintly Church or Religion of Evil, respectively. It can be a bit more iffy in a Corrupt Church, since the character may not know of it's corruption. The High Priest usually resides in a Vatican-style Holy City, especially if the church worships an Abrahamic-analogue God.

A common variation is for the character to be a Priest King, who leads their people both spiritually and physically.

Expect Authority Equals Asskicking to be in full effect in fantasy fiction, especially if Religion Is Magic.

Compare the God-Emperor, who usually leads and is worshiped by the religion in question. There is a good chance he will carry a Staff of Authority.

Anime and Manga

 * Father Conello, the priest of Leto's Church on Fullmetal Alchemist. Evil.
 * The Elder on the Assasi Village on Tengen Toppa Gurren Lagann, who founded a Cargo Cult around an abandoned Gammen. Not evil, but does use his religion to make killing children For the Greater Good more palatable.
 * Yu-Gi-Oh has a couple of late arcs in which we start to learn who exactly our main character is and why he inhabits a puzzle, and it turns out that Seto Kaiba, an early antagonist who edged toward Noble Demon since his second return from Put On a Bus defeat, though he never quite accepted that Defeat Means Friendship, is the reincarnation of the the High Priest who served under the Puzzle Spirit three thousand years ago, and apparently only betrayed him because of Mind Control from his own dead father, the previous High Priest and the previous Pharaoh's younger twin brother. Who made the magic gold jewelry by burning Bakura's family alive.

Film

 * In the film Avatar, the Na'vi tribe Jake meets is led by a husband-wife pair: the husband is the military chief, and the wife is the high priestess. Their daughter, Neytiri, is to follow in this tradition and be the next high priestess.
 * Imhotep from the black and white The Mummy.
 * Mola Ram from Indiana Jones and The Temple of Doom.
 * High Priest Maax from The Beastmaster (third one down).
 * Thulsa Doom from Conan the Barbarian.
 * Sarm the Priest-King in the film version of Gor. The Priest-Kings in the book are nothing like that.

Literature

 * In The Bible, Israel went through a period of being ruled by "Judges" like Samuel. God was actually very displeased when the Jews asked for a regular king.
 * High Priest Hughon Ridcully is the High Priest of the Ankh-Morpork clergy in Discworld, of the sort that regards actual religious-ness as one of those tiresome things that you just have to put up with when what you really want to concentrate on is getting the pews organised.
 * In Small Gods Deacon Vorbis of the Omnian church plots to take over the Omnian High Priest post (The Cenobriarch) and usher in a new age of religious terror.
 * One of the effects of the Prophet Brutha's revelation on the Omnian church was to abolish the Cenobriarch and ("let there be a thousand voices") start a long train of schisms, meaning Omnians stopped running around ruling an empire of grandeur and oppression and the suppression of science and got busy arguing theology all the time and became harmless and handed out a lot of pamphlets. Which is a tad bit Did Not Do the Research if you look at some of the awful shit Protestants have pulled in the last four hundred years, but the Disc can be like that.
 * The Omnian in the Ankh-Morpork Watch (we never learn his exact denomination) is actually named Visit-The-Infidel-With-Explanatory-Pamphlets. They call him Visit. Of course, given Brutha achieved his great transformation from stupid youth to politically savvy prophet largely due to absorbing an Expy of the Great Library of Alexandria before it was burnt down, there may be rather sound theological reasons for those pamphlets. Although Visit was invented before Brutha.
 * Deacon Hollingshead, the head of the Dominion of Jesus Christ in Julian Comstock.
 * Tenar/Arha, the Eaten One, the high priestess of the Powers of the Earthsea Trilogy.
 * Lord Reston in Just Ella by Margaret Peterson Haddix, who is priest to the king (although the king is technically the leader of the church.)
 * Stranger in A Strange Land has Foster, the founder of the Church of the New Revelation, and his successor, Supreme Bishop Digby. Valentine Michael Smith, as the leader of the Church of All Worlds, also fits.
 * High Priest Jakan, head of the Yuuzhan Vong religious caste, is a recurring supporting villain during the last third of the New Jedi Order (and was the father of Elan, a one-off villainess from earlier in the series). His boss, Supreme Overlord Shimrra, is somewhere between Priest King and God-Emperor.
 * High Priestess Viviane and Archdruid Taliesin in The Mists of Avalon.
 * A Song of Ice and Fire has a Pope-equivalent called the High Septon. The ones seen in the series have been fairly bad, including a corrupt glutton who was killed by a starving mob; the glutton's substantially (but not totally) better replacement, who was killed by political enemies; and most recently, an incorruptible, but fanatical and misogynistic Knight Templar.
 * In Mistborn Lord Prelan Tevidian is High Priest of the Corrupt Church, one of the chief lieutenants of the Lord Ruler and . There is a faction in his church, led by the Steel Inquisitors, that want to get rid of him and put the head Inquisitor, Kar, in his place.
 * In John Carter of Mars the title of "Holy Hekkador" basically means "Priest King" among the Therns. During the time of the novels, it's held by Matai Shang, very much a villain.
 * The Green-Sky Trilogy has D'ol Falla, described as high priest of the Vine. Since the Root of the Vine is all that stands between the good people of Green-sky and the revelation of a horrific truth, the high priest of the Vine is the ultimate authority on the planet. She lives in the Vine Palace at the heart of the Temple Grove.

Live Action TV

 * Merlin has had three. Nimueh was the High Priestess of the Old Religion until her death at the end of season 1. It was revealed later that Morgause had become the new High Priestess, and when Morgana killed her as the blood sacrifice to open the veil between worlds, she became the new High Priestess.

Mythology

 * Aaron, in the Exodus.

Tabletop Games

 * Magic the Gathering: Elesh Norn, Grand Cenobite is the leader of New Phyrexia's white-aligned faction, the Machine Orthodoxy.
 * Warhammer 40000 has several:
 * Ecclesiarch, the head of the Adeptus Ministorum, or Eccelsiarchy, the state church of the Imperium of Man.
 * The Fabricator-General of Mars, the leader of the Adeptus Mechanicus and senior priest of the Machine Cult.
 * Space Marine Chapters have their own Chapter cults revering the God-Emperor and their Primarch, led by the Master of Sanctity or High Chaplain.

Video Games

 * Galius from Exit Fate, High Priest of Cento while also Governor of Oischin.
 * Habaruku/Habalk in Breath of Fire 2 is the High Priest of the Church of Eva.

Web Comics

 * From Order of the Stick:
 * Redcloak is the high priest of the Dark One.
 * Malack in The Empire of Blood is the high priest of Nergal.
 * Angelo from Our Little Adventure is the high priest of 'Angelo's Kids.'

Western Animation

 * The Fire Sages in Avatar: The Last Airbender seem to be this, only 1) there's a roughly equal group of them and 2) they spend most of their time on an island separate from the rest of their countrymen and 3) it's unclear what the tenets of their faith are supposed to be, anyway, besides supporting the Avatar and crowning the Fire Lord.

Real Life

 * The Pope for Catholicism.
 * The Eastern Orthodox Patriarchs.
 * Egypt often actually had these; not of the entire 'religion' so much as of specific powerful cult-centers, since a particular god in ascendancy generally only had one location that was at the center of his or her worship. Since it behooved the ruler to be aligned as closely as possible with the most important of the gods and vice-versa, and since Pharaoh was a religious position, High Priest was often a highly government-affiliated job.