Servant

Nature
Servants are Heroic Spirits summoned by the Holy Grail. Once summoned, they can be classified as familiars as long as they are bound to a Master. Servants are legends from the past, present, or future. Because summoning even one heroic spirit is a miraculous occurence, summoning seven in their pure forms would be beyond the Holy Grail's power. Thus, to facilitate the process, Servants are summoned into one of seven vessels prepared beforehand. These vessels are classified based on their primary roles. Heroic Spirits can be summoned into any "class" that reflects the abilities they had in life. While they generally appear as they were in their prime, those with some kind of curse or strong attachment to their appearance can even be summoned in the form they had just before death.

Although too powerful to be controlled by humans, the prospect of having a wish granted by the Holy Grail serves as incentive cooperate with a Master. A Master who is chosen to participate in the Holy Grail War possesses three Command Spells that, when invoked, forces the Servant to obey the Master's orders. However, few Servants actually appear to have a wish, with only True Assassin and Saber expressing theirs while the others are either content to serve their Master or have other goals entirely.

It is to be noted that originally, the Servant system was designed to summon only the souls of "true" heroes - benevolent, honorable, and selfless protectors of humanity and justice. But since the corruption of the Holy Grail in the third Holy Grail War, evil spirits can be summoned. These entities can still be considered to be Heroic Spirits if they were widely worshipped, respected, or feared in life.

Summoning


In order to call forth a specific Servant, a material connection between the summoner and the Heroic Spirit is required. This is particularly true if one wishes to summon an exceptional Servant.


 * King Arthur: Avalon, the sheath of Excalibur.
 * Heracles:A slab of rock from a temple.
 * EMIYA: Rin's Pendant
 * Medusa: Mirror dug up from a temple in Eritrea. An item with ties to an old Earth goddess of Greece.
 * Medea: Literature, from Colchis, with ties to Medea.
 * Kojirou: The mountain gate.
 * Hasan: Since Hasan is the origin of the word Assassin, the class of Assassin itself is Hassan's catalyst.
 * Chu Chulainn: A jewel on which is engraved an original rune inscribed by Chu Chulainn. It had been crafted into earrings.
 * Iskander: A shard of cloth from his mantle.
 * Gilgamesh: The first snake's Shed Skin.

If the summoner has no cataylst to summon a servant, the Holy Grail would automatically pick a Heroic Spirit out of compatibility to the summoner. In Ryuunosuke Uryuu case, the Holy Grail picked Gille de Rais because of their similar personality.

When summoned, Servants are imparted with knowledge of technology, culture, science and terms of the era they were summoned into, as well as skill in at least the language of their Master, if not all languages. This is largely to prevent Servants from periods significantly before the era of a Grail War in question from suffering crippling culture shock which would otherwise prevent them from fulfilling their duties, and also enable them to blend in with that era's society. This is a necessary to avert such problems as:
 * A Servant terrified of modern technology (such as electronic devices) and believes them to be sorcery.
 * A Servant cannot cope with modern era surroundings and thus suffers from depressions. This might otherwise also happen to a Servant that is summoned in his past life homeland and finds it is altered by modernization.
 * A Servant finds modern common knowledge ridiculous and even comical (such as the world is spherical and revolves around the Sun).
 * Limits to the abilities of certain Servant classes. For example, an Assassin dumbfounded by modern security systems; a Saber, Lancer, or Archer that fails to understand modern weaponry; a Berserker that is confused by modern surroundings and thus goes on a rampage; a Rider who is unfamiliar with driving modern vehicles; or a Caster that is superstitious of or easily fooled by electronic devices.
 * A Servant behaves in a manner that attracts the attentions of modern civilians, or using weapons against them, and thus apprehended by the authorities, or carted off to lunatic asylum.

Without such knowledge, a Servant's potential would be crippled. This knowledge does not just cover history but all aspects of "modern" life during the Grail War in question, to the point that Servants can find things that would have been unthinkable in their lifetimes to be mundane or even worthy of scorn. As an example:
 * Arturia Pendragon of medieval era claims that she can fly aircrafts through her Riding skill. She is also able to ride a motorcycle and drive Irisviel's Mercedes without any difficulties, and is even able to enhance their potentials.
 * Iskander of ancient Greece knows that the world is spherical. He also knows how to use modern money, order his T-shirt through postal service, buys a video games console and a video game CD, much to Velvet's chagrin.
 * Berserker of the same era as Arturia uses a modern machine gun against Saber and is able to fly an F-15 and utilizes its armaments. However, this is due to his Knight of Honor Noble Phantasm rather than knowledge provided to him as a Servant.
 * Diarmuid of medieval Ireland knows that the Mercedes' engine of a vehicle driven by Saber is automatic just by hearing its engine. He calls it "an engine equipped with an automatic drive".
 * In Fate/Hollow Ataraxia, some Servants, like Gilgamesh, Medea, Cu Chulainn, Arturia Pendragon and Medusa from different time periods can be seen wearing modern attire and using modern appliances. In Fate/Zero, Gilgamesh of ancient Mesopotamia wears expensive modern clothing.

Spiritual Body and Material Body
“Spiritual Body” is a word that describes an existence with spiritual properties. In other words, a shape is constructed without relying on components with physical properties. On the other hand, “Material Body” means something that is identical in structure as our flesh bodies. A Material Body, just like us, cannot walk through walls, and will hurt and become wounded when beaten with an iron baton. However, a Spirit Body is capable of completely disregarding such physical interference. Attacking a Spiritual Body with a baton or sword (unless they are magical items) will only hit empty space.

When Servants materialise, they acquire Material Bodies in this world. They can also switch to Spiritual Bodies through their will. Spiritual Bodies have the advantages such as low mana consumption, and difficult to be detected by enemies. One of the properties of a Spiritual Body is that it is unaffected by physical interference, but conversely it is difficult for a Spiritual Body to affect a Material Body. As a result, Servants Materialise when engaging in combat.

Although both are Material Bodies, the composition of Servants and Humans are drastically different. Naturally, it is impossible to transplant a portion of a Servant’s Material Body to a human. However, Shirou Emiya was able to successfully transplant Archer’s left arm to replace his own lost left arm. How is this possible? It is because Shirou and Archer – Heroic Spirit Emiya are the same person.

Servants can revert to spirit form when not in battle at will, to reduce the burden on their Masters. In this form they can pass through inorganic substances that aren't dense with mana; they are also invisible to the naked eye (except for the Master they connected with) and most forms of scrying in this state, facilitating the concealment of their identity. When Lancer invaded the Emiya mansion, he used his spirit form to infiltrate the house. He subsequently reverted to physical form to drop from the ceiling into the living room. They cannot be affected by normal interference when dematerialized, but need to materialize for battle. As Human Spirits are they able to consume the souls and minds of people and convert them into energy. Their basic abilities do not change from such nourishment, but they become tougher as their magical energy capacity increases.

How to Defeat A Servant
When a Heroic Spirit emerges into this world, he first acquires a Spiritual Core. The Heroic Spirit then materialises as the body envelopes this Spiritual Core. In order to defeat a Heroic Spirit, one must inflict damage to the Spiritual Core. The Spiritual Core gradually diminishes as a result of massive magical energy expenditure or sustaining bodily damage. Under these adverse conditions, the Heroic Spirit’s expenditure of magical energy will escalate, and should damaged be inflicted through powerful magical energy, curse, or Noble Phantasm, the Spiritual Core will be destroyed, and the Heroic Spirit will no long be able to remain materialised. The heart and head are connected directly to the Spiritual Core, thus they are the weaknesses of Heroic Spirits. Sustaining damage at these locations will significantly weaken the Spiritual Core.

Battle of Servants
The battle between Servants can be called a process of gradually shaving off the magical energy that forms the their bodies. Attacks that consume a great amount of magical energy will inflict a massive amount of damage on the opponent, but it will also weaken yourself in the process. In order to inflict a great amount of damage with minimum expenditure of magical energy, it is necessary to collect intelligence regarding the enemy and assault his weakness.

Classification
Heroic Spirits summoned by the Holy Grail are place into one of seven categories. The seven standard classes are Saber, Lancer, Archer, Rider, Caster, Assassin, and Berserker. According to Rin, servant classes are changed between each war, so other classes, such as Avenger created by the Einzberns in the Third Holy Grail War, can also be summoned. The Three Knight classes are the only Servants who will definitely be summoned according to the framework of the Holy Grail War, allowing for variation in the rest of the classes. More than one version of the same class cannot be summoned, even if all the Masters were to use the variation in the summoning chant to get a Berserker-class Servant.
 * Saber: Servants placed within this class are agile and powerful melee warriors. It is commonly assumed to be the best class overall, with high ratings in all categories. It is one of the three Knight classes, together with Lancer and Archer and also possesses the Riding skill like the Rider class.
 * Lancer: Servants placed within this class are very agile and skilled with long-range melee weapons, such as spears, lances, etc. It is one of the three Knight classes, together with Archer and Saber.
 * Archer: Servants placed within this class are usually proficient with projectiles and can survive longer without a Master nearby, thanks to their special ability Independent Action; the strongest Archers can be difficult to control at times, in fact, due to their near-total independence from their "Masters". It is one of the three Knight classes, together with Lancer and Saber.
 * Rider: Servants placed within this class place emphasis upon speed and powerful Noble Phantasms, which often include their mounts. Their special skill is Riding, which allows them to fully utilize abilities of their mounts (which can range from simple horses to mechanical vehicles to divine or supernatural creatures.).
 * Caster: Servants placed within this class are adept in magecraft and have a special ability akin to Reality Marble, called Territory Creation, which alters or creates space around them to enhance their sorcery.
 * Assassin: Servants placed within this class are always, as a rule, one of the 19 Hassan i Sabbah, the leaders of the clan of the Hashshashins who passed their name down (although this rule does not hold absolutely true in the Fate/Extra reality). The Assassin in Fate/stay night summoned by Caster is an exception, an aberration in the system, as he was summoned by another Servant. This rule comes from how the word "assassin" itself finds its etymological roots in that clan. The Assassins' special ability is Presence Concealment, which allows them to remain undetected. Offset by their stealth is their weak combat skills. Due to this, Assassins often target Masters instead of Servants.
 * Berserker: Servants placed within this class are always heroes who have gone berserk in their lifetime. This trait allows them to use the special ability Mad Enhancement, which trades their consciousness (i.e. sanity) for a large power boost. Most Masters are incapable of controlling their Servant once Mad Enhancement has been activated, which eventually results in their death.
 * Avenger: It is not one of the seven normal classes, and it has only been used once as a unique container for Angra Mainyu in the Third Holy Grail War.
 * Saver: This is an irregular class in the Holy Grail War of the Moon Cell in Fate/Extra. The only case is of the class is Saver.
 * Funny Vamp: Funny Vamp (ファニーヴァンプ) is the class granted to Arcueid Brunestud by the Moon Cell should she participate as a Servant. While she takes on the Berserker class instead, Funny Vamp reflects her whimsical nature and her status as a creature that drains blood, physical energy and money from men.
 * Ruler: Servants placed in this class govern the Holy Grail War of Fate/Apocrypha. Joan of Arc is placed in this class.
 * Beast: This class is a special container for the 666th Beast in Fate/Prototype.
 * Monster: Monster is not a Servant classification, but rather the title given to the irregular being, Shiki Ryougi, who appears within the Holy Grail War of the Moon Cell.

Container Parameters
Unmodified by the strengths and weaknesses of specific Heroic Spirits, the containers of the seven standard Servant classes of the Fuyuki Grail War possess known base parameters. Heroic Spirits are not affected when summoned, so they may have statistics higher or lower than those of the class container.

Holy Grail War

 * For more detail about Fuyuki's Holy Grail War, see Holy Grail War.

Some details of the Third Grail War are mentioned in Fate/hollow ataraxia. The events of the Fourth Grail War are described in Fate/Zero. The events of the Fifth Grail War are detailed in Fate/stay night and Fate/hollow ataraxia.

Even though the setting is in Japan, there are so few Japanese Heroic Spirits summoned in the Fuyuki Holy Grail even if they have geographical boost advantage because the Holy Grail is a western Christian concept.

Fate/Extra
The events of the Grail War of the Moon Cell are detailed in Fate/Extra and Fate/Extra CCC.

Fate/Apocrypha
The events of the Grail War are detailed in Fate/Apocrypha.

Servants for the canceled game Fate/Apocrypha project.

Fate/Prototype
The events of the Grail War of Fukutoshin are detailed in Fate/Prototype.

Fate/strange fake
The events of the Grail War of Snowfield are detailed in Fate/strange fake.