Caster (キャスター, Kyasutā?), Magus and Heroic Spirit of Spells and Sorcery, is one of the Four Cavalry Classes among the seven standard Servant classes summoned for the Holy Grail War. Servants placed within this Class are usually adept in magecraft, and the only qualifying condition is the mastery of sorceries of the highest caliber compared to the specific parameter requirements of the other classes. Due to not requiring any strong statistics, they generally have low combat abilities, and due to the majority of Servants having some form of Magic Resistance, this Class is thought to be the weakest of all seven. They make up for this with other means, using magecraft that no longer exists in the current age and, no matter which Heroic Spirit is of which Class, possessing many possible ploys to be used against enemies. Those of the Saber Class can likely challenge any Caster who uses magecraft as their main offensive ability without needing to plan due to their high Magic Resistance, while those of lesser resistance like the Rider Class may require more strategy. Their class abilities are Territory Creation, altering the surrounding lands in favor of their sorcery, and Item Construction, which allows the magus to create magical items and tools.
- Servants marked with ‡ are also able to be summoned by the Protagonist in the Grand Orders.
- Servants marked with ⁜ are those who change class mid-story but do not display characteristics substantially different from the original class.
Servants possessing the Class of Caster for special reasons unrelated to a proper summoning.
|Arash (Fake)||Grand Order||Joan of Arc (Alter)|
|Elizabeth Báthory (Halloween)||Grand Order||Protagonist|
|Marie Antoinette (Swimsuit)||Grand Order||Protagonist|
|Nero Claudius Caesar (Swimsuit)||Grand Order||Protagonist|
Other qualifying heroesEdit
|True Name||Current Class||Notes|
|Alexander the Great||Rider||Fate/Ace Royal only|
|Amakusa Shirou Tokisada||Ruler|||
|EMIYA||Archer||Fate/Ace Royal only|
|Medusa||Rider||Fate/Ace Royal only|
|Peter the Cruel||None|||
|Vasco da Gama||None|||
 Fate/complete material III: World material - Records of Heavens Feel - Servant System: Class, p.015
A "Servant Class" is a container prepared for materialising a Heroic Spirit that is summoned into the current era as a Servant.
There are seven Servant Classes: Sabre, Lancer, Archer, Rider, Caster, Assassin and Berserker. Since there cannot be repeats of any one class, the seven Servants participating in a Holy Grail War will be of different classes.
Heroic Spirits determine their classes on the basis of their characteristics, and then summoned as the Servant of the corresponding class. For instance, the only class appropriate for Artoria is Sabre, but Hercules, who was said in legends to be proficient with all weapons, can be summoned into all classes but Caster. The affinity between the Master and the Heroic Spirit will determine which class the Heroic Spirit will be summoned into. However, the Einzberns, as one of the "Three Founding Families" and well-informed of the rules of the Servant system, was able to preemptively interfere with the system and summon Hercules as Berserker.
Among all the classes, Sabre, Lancer and Archer are also called the "Three Knights". They are frequently Heroic Spirits from the Age of Gods when sorceries were common. Due to high magic resistance, modern magi are unable to inflict damage to them.
The Assassin class is special, as the only qualifying Heroic Spirits are the Hassan al-Sabbah's.
Knight of the Sword. The compatible Heroic Spirit naturally needs to possess legends as a knight of sword, as well as the highest levels of attributes in all but MGI. Class Abilities include Magic Resistance and Riding. Also, compatible Heroic Spirits usually excel in delivering powerful burst attacks.
Knight of the Lance. Its high qualifying conditions are second only to Sabre. Attributes are excellent overall, in addition, AGI must be high. Of course, Servants of this class are proficient in hit-and-run tactics that capitalise on range and speed. This class includes many Heroic Spirits who were knights.
Knight of the Bow. A class that excels in possessing powerful Noble Phantasms. The qualifying condition is not attributes, but the possession of powerful projectile weapons or special abilities related to projectile weapons. Highly effective as scouts. They have not only the Magic Resistance ability of the Knight Classes, but also the class ability of Independent Action.
Mounted soldier. Heroic Spirits who rode mounts (not limited to living creatures) qualify for this class. Although attributes tend to be lower compared to the Three Knight Classes, this is compensated by the abilities of the mount described in legend. Besides Magic Resistance, class abilities also include high Riding.
Magus. Qualifying conditions only include mastery of sorceries of the highest calibre. Due to this trait, the qualifying Heroic Spirits tend to have low combat abilities. In addition, since the majority of Servants have Magic Resistance, this class is thought to be the weakest of all.
Assassin. The only qualifying Heroic Spirits are the generations of Hassan al-Sabbah's, and one of them would be summoned. All of them do not have glorious legends as heroes, thus possess low attributes. Class ability is Presence Concealment, and the use of this ability during battle is the lifeline of Assassin.
Mad Warrior. Heroes who have gone berserker during battle qualify for this class. Normally it is considered ideal if a Servant can wield power at the level of the original Heroic Spirit, but "Mad Enhancement" allows for the attribute enhancement of the Servant beyond the ability of the original at the cost of sanity. A class originally used to enhance weak Heroic Spirits.
- ↑ Fate/Zero - Volume 2
- ↑ Fate/stay night Heaven's Feel: Day 4 - Saber explains the rules
- ↑ Fate/Grand Order - Amakusa Shirou Tokisada, Interlude I
- ↑ TYPE-MOON Ace Fate/Grand Order, p.126
- ↑ TYPE-MOON Ace Fate/Grand Order, p.125
- ↑ 7.0 7.1 7.2 TYPE-MOON Ace - Volume 11