Holy Church

The Holy Church (聖堂教会), also referred simply as "the Church", is a international religious organization apparently styled after the real. It is a powerful faction in the Nasuverse, with several important characters in the games being its active or former members. It appears to coexist peacefully with the Mage's Association, though this seems to not have always been the case. They sometimes act as an arbitrary power in the Mage's Association's internal disputes like the Holy Grail Wars. The Thaumaturgical Theory of the Church, in form of its Holy Sacraments, is the most widespread and well stabilized in the world.

Activities
The Church holds a great level of animosity towards Vampires. There is no great reason for specifically hunting them down with such fervency other than that they are a group that only likes humans. Beings that are not human can be controlled, so they don't need to be made into enemies. They can coexist with completely different races, but Vampires are beings born from humans. They carry the possibility of "infection" to other humans, so they are treated like diseases that need to be cut off.

The Church mainly began to take this view with the founding of the Burial Agency, as it was created for the very purpose of killing them. If they don't take such a stance, it has no real reason to exist. As their faith is very shallow, they have a necessity to affirm the importance of their roles. That same stance continued to escalate within the Church since then.

Known members

 * Caren Hortensia.
 * Ciel.
 * Eiri Fumizuka.
 * Kirei Kotomine.
 * Risei Kotomine.
 * Narbareck (co-founder of the Burial Agency).
 * Merem Solomon.
 * Michael Roa Valdamjong (excommunicated after becoming a vampire).
 * Mr. Dawn.
 * Riesbyfe Stridberg.
 * Sancraid Phahn (false allegiance, his true loyalty lies with the Templars).
 * Yuika Suse.
 * Shirou Kotomine.

Abbeys
Abbeys are monasteries that house individuals like Caren Hortensia. She was admitted to the Citeaux Abbey, but she was permitted to leave on errands pertaining to exorcism unlike the others in the abbey.

Assembly of the Eighth Sacrament
The Assembly of the Eighth Sacrament (第八秘蹟会) is a special agency made up of a group of special clerics charged with the research, recovery, and managing of holy relics scattered across the globe. The items called holy relics include the remains and blood of saints, the nails that crucified Christ, the holy cross, the thirty silver coins of Judas, and other items with the holy attribute. The members follow the "Eighth Sacrament" outside of the, the seven graces that God bestows in the Catholic faith: Baptism, Holy Eucharist, Matrimony, Holy Orders, Confirmation, Penance, Anointing. It is a "Grace that doesn't Exist" in the rightful faith or a "power separated from the faith", meaning the members trained to retrieve the hidden relics do not fear being involved in heretical power such as magery to accomplish their goals. It is the lowest of the special agencies.

One aspect of their job is to watch over any claim of the Holy Grail, which has great importance the doctrine of the Church. One such claim includes Fuyuki City's Holy Grail War. The send a supervisor from the agency, such as Risei Kotomine and Kirei Kotomine, to act as a mediator between the Church and the Mage's Association. As of the Fifth Holy Grail War, they are investigating the 726th claim of the Grail, and they are tasked with recovering it if it proves to be real, or disputing it if it proves to be false. In reality, they already know it is not the genuine artifact, and would generally ignore a special device which seeks the "Root." The path leading to the root can be said to lead to the "outside" of the world, meaning that it will not bring any effect to the "inside." The Church only cares about the visible world, and finds the magi’s pursuit as a meaningless plan. The ability for the Holy Grail to realize wishes is "omnipotent", granting it unlimited, mysterious power to change even the ‘inside’ of the world. Such a power could become an existence which threatens their belief, so they feel the need to keep it from falling into the wrong hands. They wish to guide the wish made with it, such as backing Tokiomi Tohsaka's "boring, meaningless wish." Tokiomi is one of the most right-winged magi, compared to others who would pursue the gifts of mundane riches, prestige, desires, power, all of which can be fulfilled "within" the world. He wishes to reach the root, which has nothing to do with the "inside."

Burial Agency
The Burial Agency (埋葬機関) is a group of special Inquisitors gathered by the Church. The original Michael Roa Valdamjong, then a priest of the Church, created a burial doctrine, the base of the Burial Agency, back in the twelfth century. He created it along with the original Narbareck, the first technical leader of the Agency, called the Burial Classroom at the time. She knew of Roa's plans to become a vampire, but didn't stop him. Though they are known as the most professional Inquisitors, they are not actually responsible for stamping out heresy, leading them to be called Executors or killers.

They are not meant to be exorcists, but simply those who kill demons. The organization operates and scouts entirely on ability. Anyone can become a member if they have the power and the will to destroy heretics and whatever else the Church finds "inconvenient." Faith is a secondary condition compared to the necessary power to obliterate the heretical, though they will baptize the members. It is made up of seven main members including the leader, and an eighth member, an exceptional candidate from the Church, is in reserve, though they are changed often because they keep dying during missions. Those on the outside see it as a group filled with magi who loved to explore the taboo, people who enjoyed enslaving the captured heretics, gun nuts, and maniacs with insatiable bloodlust.

Each member works alone under most circumstances, and they will not cooperate with foreign demon hunting organizations. The members gain powerful privileges and influence, and they will even go against the wishes of the Church without orders to eliminate heretics. They'll go as far as to skewer a Bishop if he is possessed, leading to whispers calling it the most heretical section of the Church. The Agency does not like that Arcueid has sometimes taken requests from the Church to cooperate in eliminating Dead Apostles, and they would like to seal her, despite her not being on their list, should an opportunity show up. Merem, an Ancestor, cooperates with the Burial Agency because, as he is a collector of treasures from all ages all around the world, he wants to be near the treasures that the Church sealed away.

El Nahat, another Ancestor, is also forcefully cooperating with the agency; he's being stored in a prison of mirrors and his stomach is used as a scripture. The "Alien Stomach World" operates as a summoning terminal for his main body and it is considered to be the most powerful resort of the Church against the Dead Apostles. It is carried and used by the first or second members of the Burial Agency.

Members of the Burial Agency:
 * 1.Narbareck, 1st member and leader of the agency.
 * 2. ???, 2nd member.
 * 3. ???, 3rd member.
 * 4. ???, 4th member.
 * 5. Merem Solomon, 5th member.
 * 6. Mr. Dawn, 6th member.
 * 7. Ciel, 7th member.
 * 8. ???, 8th spare member.

Chivalric Orders
The Chivalric Orders are the Knights (騎士団) that make up the main military body of each church. It is one of the few groups that still uses halberds, but its use is dying out.

They only fight to defend holy ground, according to Nrvnqsr.

Executors
The Executors (代行者) are the heretic inquisitors of the Church established by the 120th Cardinal. They are not charged with the purpose of demon exorcism, but rather have the task of demon killing and the destruction of other heretical beings. It is known as the bloodiest department of the Church, called the Shura's Den for its responsibility of punishing heresies. It takes a certain amount of willpower to be part of it, and being able to achieve the title of "Executor" signifies that one is a first-rate murderer that has passed brutal and pious training to become mankind's weapon. Kirei Kotomine was ten years old when he was made into an Executor, but he later changed positions a number of times. They have varying specialties, including those specialized and geared for magus hunting, demon killing, or vampire slaying. They also include Exorcists (エクソシスト), special kinds of priests charged as "representatives" by the bishop of a diocese. They are a type of Executor not geared for heretic hunting, but rather answer pleas for help and visit those towns to exorcise demons. While the mere likes of humans are no match for a mature demon, the real problem for the visiting exorcists is the protection of the soul. The experience of demon exorcism is said to be one that a person cannot withstand once again, making an iron faith more sought after than physical prowess. They don't fear demons, but rather they fear the breaking of their will.

The Executors also follow the Eighth Sacrament, granting the permit to stray away from the rules of their religion as long as one thing, the name of the Almighty, is protected. They are followers that do not teach the words of the Lord, but act as as His representative, His Executors, despite being mere mortals. They take part in trials that should have only been watched, and slay heretics that should have only been denied. They are those who should not have even existed, who dispel the demonic and hunt what does not exist not in the teachings of their Lord. The existence of demons has sometimes made man mistake the calculations of heaven as the powerlessness of heaven. They sought a miracle from their Lord in the incomprehensible work of the demonic, causing exceptions in the form of the Executors to be born.

They consider demons to be messenger of heaven according to their doctrine, making it so a priest teaching the words of God has no right to destroy them. They follow the idea that God is the one absolute, that which is supreme and that which is all, and that as The Holy Spirit, He is the creator of a perfect world. It is impossible for Him to allow the existence of demons to defile the world He created by violating His own children. Even with that ideal, it is a fact that they do exist, corrupting man and defiling the world, playing out miserable tragedies and comedies beyond the reasoning of man. That which ought not be taints the world of God, and so, they reasoned that even these demons, the corruptors of man, are a vital part of the world the Lord constructed and one of His precious creations. They simply follow that if it is the work of the holy to strengthen the goodness of man, then what strengthens the evil of man is the demonic. The Executors are those who hunt that which is not in their doctrine, meaning that they can not be held back by that doctrine, and allowing them to annihilate even Their Lord's own demonic creations. That is the one point that distinguishes them from exorcists.

The Templars
The Order of the Templars (テンプル騎士団) is a small but powerful faction in the Church that has only appeared in Fate/Prototype. Although they have a considerable amount of connections and allegiance to the Church, the Order of the Templars is often not considered a part of the Church. They are in truth a separate independent organization of their own and hold only loyalty to themselves. They seem to specialize in heretic hunting and often lend some of their own heretic hunters to the church, when necessary. Sancraid Phahn is a member and one of their top Heretic Hunters.

Artifacts

 * Alien Stomach World.
 * Black Keys (黒鍵) are charms used by agents of the Church to repel demons. They take the form of long rapier-like swords (although they are generally thrown as a dagger or used to stab opponents). They are considered to be symbolic and have weak attack power, but its attack power is still enough to pierce through concrete walls. The amount of skill required to properly wield them causes the Black Keys not to be used often. They excel at interfering with and damaging spiritual phenomena rather than damaging them physically. The effect on beings like Servants is minimal but they are very effective against the creatures that are being hunted down by the Church, like the Dead Apostles. If they hit the shadow of a target, the target will be unable to move their body, leaving them to the mercy of the black key's wielder. It could also be used to track down and seal or injure a target until its wielder tells it to stop doing so, or unless it is destroyed or neutralized by an outside force. Expert Executors are capable of materializing the blades by passing prana through an object, such as pages of a bible, allowing them to carry and conceal hundreds of hilts at a time. This practice falls category of sacraments rather than thaumaturgy. They are used by Ciel and Kirei Kotomine.
 * Keys of Providence (摂理の鍵) are types of Conceptual Weapons used for purification, which is the forcing of natural laws onto the vampire and baptizing their flesh to turn them back into ash. They open the structure of physical body and lock it back into its original form if the target was a Catholic during their human life, or if they have devoured or sucked the blood of a Catholic. They lack much of an effect if they were not Catholic, on the other hand, they will have some effect on a Christian vampire even if the user is a non-Christian. If both are believers of the faith, their power is absolute. Black Keys are types of Keys of Providence.
 * Holy Shrouds (聖骸布) are cloths used to wrap around the remains of . Kotomine owns the Shroud of Martin and Caren Hortensia owns the Shroud of Magdalene. Archer's cloak is also made from a Holy Shroud.
 * Scriptures (聖典) are powerful Conceptual Weapons that have only been granted to a few selected Executors. Kirei Kotomine believes weapons of this level could potentially allow a person to defeat a Heroic Spirit. The holy shield Gamaliel is used by Riesbyfe Stridberg and the Seventh Holy Scripture is used by Ciel