Caster (キャスター)

Caster|キャスター}} is the Caster-class Servant of Souichirou Kuzuki in the Fifth Holy Grail War of Fate/stay night. She also acts as the Master of another Servant, Assassin.
==Profile==
===Identity===
thumb|left|Medea younger appearance
Caster's identity is , an unfortunate princess who was labeled as a witch in Greek mythology. She was the princess of who possessed the . Her father, King of Colchis, excelled at magic, and as his daughter, she was also practiced in such ways. Her personality at the time was far from what would be called a witch, and her fate became confounded after the hero famous from the Argo Expedition, , appeared before her.
Jason argued with King , the usurper of his father's country , and eventually made him promise to return the country upon traveling far east to Colchis and returning with the Golden Fleece. He was supported by the Goddess , and upon realizing that the King of Colchis was unshakable, she decided to control Medea's mind to help Jason. Medea was made to blindly love Jason, which resulted in her betraying her father and her country for a foreigner she had never seen. Her abilities allowed her to nullify her father's magic and the enchanted fire-breathing oxen, which gave Jason the chance to obtain the Golden Fleece.
thumb|left
King Aeetes was infuriated, and decided to personally lead his army to capture Jason before he left the country. Aphrodite once again used Medea to assist Jason's escape by forcing her to kill her own brother, . While she only knew Jason by name, her forced love caused her to board his ship, the , and slice her brother into pieces right before the eyes of her pursing father. The King, overcome by grief, ordered for the collection of the pieces of his dead son, which allowed for the opportunity for the Argo to escape its pursuers.
thumb|left|Medea casting magecraft in her pot
Upon returning to the safety of his native land, Jason asked for the return of his country as promised, but King Pelias refused. He formed a plot to kill Jason, and Jason was forced to rely on Medea's magic three times to escape from the danger. She eventually came up with a plan for Jason, where they invited Pelias to visit and displayed her magic. They killed his servant in front of him and revived him with her magic to display a spell of immortality. She offered to cast the same spell on the King, who was overjoyed at the prospect. He willingly gave his body to her, which was left in pieces and thrown in the sea.
Jason became the king afterward, but his fellow did not approve of his conduct, and most of all, they disapproved of Medea's very existence. They denounced her as a witch who betrayed her country for a man, killed her brother to save herself, and now had taken the throne by deceit. They were both chased out of the country, and fled to where they were welcomed by the king. She finally found a peaceful rest in this land after her abduction and denouncement, but it did not last long.
thumb|Caster's memories of exile
The King of Corinth took a liking to Jason, and decided to have his daughter marry him. Jason also decided to choose the young daughter over Medea, which lead to her exile. Her actions afterward were those that have truly marked her as a witch. She appeared at Jason's wedding, and burned all who attended with her magic. Everyone except for Jason was killed, including the King of Corinth and his daughter, and Medea's fate after she left Corinth is unknown. As her life was filled only with betrayal, it is said that the princess became a true witch and continued to roam the Greek lands.
===Appearance===
Caster's appearance is much like a witch that would be seen in a fairy tale. She wears a hooded bluish-purple robe throughout Fate/stay night, and her appearance remains hidden for most of the story. Her face is only shown briefly after being slain by Archer during Unlimited Blade Works. She generally wears a much more casual attire during Fate/hollow ataraxia to match her attempts at being a normal wife for Kuzuki. The outfit consists of a black top with a jean jacket and long tan skirt. She still dons her robe if she has to enter into battle.
===Personality===
While she was about to disappear after killing her first Master, she lamented that she would disappear before being able to fight. She would disappear unable to do anything as a pitiful Servant summoned only to be trampled upon. While such a situation was vexing, it wasn't out of the ordinary for her. It had always been that way for her, as she has always been used as a tool by others. She had always been treated unreasonably, and she was never once understood by anyone. Her life was always controlled by someone else, and her mind was destroyed at a young age to save a hero chosen by the gods. She was cursed to blindly love a man she had never seen just because he was favored by the goddess of beauty, which led to her being forced to betray her own father and country.
She has no true memory after that point. She was brought to an unfamiliar country after betraying her father for a man, and made into a witch that cut apart her own brother and threw the pieces into the sea to escape her native country. After all that happened, even the man who had wanted it done cast her aside in order to become king after saying he could not marry a witch. Her origin is that she controlled and taken to an unknown country, marked as a witch, and thrown away by the only person on which she could rely. There is nothing people can blame her for, and while the people around her were aware of that fact, they still demanded for her to be a witch.
People wanted a convenient scapegoat that they could blame for any disaster, whether it is an evil to protect the king or an evil to be on the end of evil superstitions. She was part of a unchanging pattern where people demand easily understandable evil to reassure themselves of the own goodness. She was considered the perfect sacrifice in that regard with the only person she could rely on, her father, in a distant country. Nobody defended her, and they gladly blamed her for all the ugly things in the world. They decided every ugliness was the witch's doing, from being poor, to hating others, the fact that humans are ugly, or even that people die.
She merely accepted that fact, and she decided because she can only live as a witch, that she would act as a witch. She imposed such a reason of existence on herself as it is the only role people gave to the girl called a witch who never had a free will. She swore to show them the ugliness of their wishes that they demanded of her. If they do not know their own ugliness, they can stay ignorant, go to hell for their own crimes, and suffer forever. They won't be able to get out of hell, where they will suffer forever as criminals because they do not know what crimes they have committed.
Nobody actually wished for such a thing, and neither did she wish for it. She seeks revenge against her will, without having any wish for herself. Her entire outlook changed upon meeting Kuzuki.
Her main talents lie in plotting and crafting plans. She likes reticent men of sincerity and girls in adorable clothes, and she dislikes muscles. She's merciless against mature women. She doesn't like to be called a "witch", and while she will forgive someone once, she will prepare an appropriate punishment for those who call her a "witch" twice.
==Role==
===Fate/stay night===
Caster was originally summoned by a magus from the Mage's Association before the start of the Holy Grail War. He was a legitimate magus who was in his thirties with a medium build and few other noteworthy characteristics. He had no drive for combat, but still dreamed of victory while waiting for the other Masters to kill each other. She quickly gave up on him within a few days while planning to sever her connection to him. She made him use his Command Spells on meaningless things, so that he would have no control over her. She acted as an obedient Servant and filled the man's conceit in order to make him believe that she would still be faithful without them, and upon using his third Command Spell, she killed him with Rule Breaker because she did not like the fact that the contract still existed.
On the verge of her spiritual body dissipating, she stumbled upon Souichirou Kuzuki at the foot of the Ryuudouji Temple. Caster begged this stranger for his help; Souichirou obliged without hesitation, forming a new contract with her. He then brought Caster into the temple and attended to her recovery. Caster quickly fell in love with Souichirou, for he was the first man to show her genuine kindness, dedication and loyalty. Her primary objective shifted from obtaining the Holy Grail for herself to simply preserving their short time together. To achieve this end, she siphoned Mana from the populace of Fuyuki City and fortified her position on Mount Enzou.
She is known to others as an honored guest of the Ryuudou family, permitted to live at their temple until the preparations for her marriage have been finalized. She is thought of as a gorgeous and talented yet mysterious woman of high stature. Her presence has attracted the attention of many trainee monks.
Caster found and killed the regular master for Assassin before he could do the summoning. She used the mountain gate as a cataylst to summon a fake servant Assassin known as Sasaki Kojirou.
Caster is killed in every scenario of Fate/stay night.
====Fate====
In Fate, her stronghold in the Ryuudouji Temple is briefly assaulted by Saber, though her own Servant, Assassin, manages to hold her back. She is later torn apart by Gilgamesh's Gate of Babylon while ambushing Shirou Emiya and Saber.
====Unlimited Blade Works====
In Unlimited Blade Works, she manages to stab Saber with Rule Breaker and negate her contract with Shirou; Caster then abducts Saber and tortures her, hoping to provoke Saber into becoming her Servant. While attempting to kill Emiya and Rin Tohsaka in the basement of the Kotomine Church, she dies protecting her Master from Archer's hailstorm of blades.
====Heaven's Feel====
Caster is killed early on in Heaven's Feel by Saber, but Zouken Matou uses one of his worm familiars to maintain her body as a puppet. Saber and Archer later destroy the puppet during a confrontation with Zouken.
====Manga====
In the manga, Caster's role both remains the same as her roles in the Fate and Unlimited Blade Works scenarios and expanded at the same time.
In the manga, Caster becomes the secondary villain or major antagonist, she manages to stab Saber with Rule Breaker and negate her contract with Shirou; Caster then abducts Saber and tortures her, hoping to provoke Saber into becoming her Servant. She later blackmails Archer into joining her. While attempting to kill Shirou Emiya and Rin Tohsaka in the basement of the Kotomine Church, she is severely wounded by Archer protecting her Master from Archer's hailstorm of blades and is hacked to near-death by the crimson knight. While she is left to die she mourns for her dead master, she survives when she is revived by Kirei Kotomine, who offers her a chance of winning the holy grail and an opportunity at revenge if she becomes his servant. This is all a deception as Kotomine is just manipulating her to allow him to have the joy of seeing her suffer and fail even more. When Caster assaults the Emiya residence she is torn apart by Gilgamesh's Gate of Babylon during her ambush.
===Fate/hollow ataraxia===
In Fate/hollow ataraxia, Caster goes about as a normal woman, normally hanging around the mall. She is the first person to discover the four-day time loop (other than the player). She also fights the dog-shadows using anti-army spells, often coming close to killing her allies.
===Fate/Prototype===
Caster retains her identity from the original novel version of Fate/stay night, but she doesn't appear within the Fate/Prototype animated special. The extended script of Prototype Material details that she would have turned Ayaka Sajyou's school building into an "alien realm" with her long-distance magecraft, and Saber would have started to lose due to Ayaka being unable to protect herself. The attack would have been stopped by Rider, who has some connections with Caster. She is still the Master of Assassin, and like in Fate/stay night, he is bound to the mountain gate.
Caster's Master is much like Kuzuki, but more of a fighter than an assassin. Similar to Ryu from , he is not a magus, and after drawing Caster, she said, "So, I can be the magus, but what good are you?" He replied "Then you should leave the killing part to me, mage."
===Carnival Phantasm===
Caster is reduced to a more comedic character within the series, repeatedly hinting to Kuzuki that she wants to marry him. She gets a full personal segment in episode 7, detailing her obsession with Saber. It is revealed that she is actually an Otaku who wants Saber, not as a servant, but rather as a pet or a doll for her to dress up or play with. The episode ends with Kuzuki proposing to her, to which she begins sobbing out of happiness and wondering to herself if she deserves happiness.
==Abilities==
Caster is a magus from the Age of Gods that far surpasses modern magi. She is something from the divine era that shouldn't exist in the Age of Man, so her abilities in magecraft are on an entirely different level than any living magus can produce. While something "solid" like completed spells cannot normally be overcome by a "liquid" such as prana, Caster compares modern magecraft to mud buildings that, while solid, can easily be washed away by the violent water current of her superior spells. Even though she is considered a witch, the magecraft she utilizes during the Holy Grail War is forbidden magic she has never before used in her life. Without a proper Master to provide her with prana and being the weakest of the Servants, she feels she must abuse such abilities to match her opponents.
She has a large amount of prana at her disposal, and at normal levels, she is capable of staying in the world for up to two days without an active contract with a Master even though she lacks the Independent Action skill of the Archer class. Due to her first Master being overly cautious of her abilities, he constantly kept her prana level below his own, so she was only able to last a brief period of time after killing him. She normally would have disappeared before finding another anchor to the world, but the Ryuudouji Temple kept her stable long enough to establish a contract with Kuzuki.
She does not need to cast her magecraft like modern magi, as incantations are unnecessary to connect herself with the world. She is always surrounded by divine mysteries of ancient lore, so magic is just something she commands like ordering her guard dog to attack. This stems from her , which allows for the activation of magecraft without connecting to her Magic Circuits or using the normal incantations for the spells. are a Thaumaturgical Theory and language from the Age of Gods that modern humans can no longer pronounce. They are fundamentally different from modern incantations due to words themselves having power during that era, while modern incantations are mainly just a means of self-hypnosis to work one's circuits. Caster's use is advanced enough that spells are activated with just a single action, allowing for High Thaumaturgy in an instant.
Her main offensive spell is , which is a volley of rapidly fired beams of light each with an A rank power of attack. Each beam is a deadly spell on the level of High Thaumaturgy with three times Shirou's entire amount of prana, capable of destroying the body of a Servant with a direct hit. Just the use of one single beam would normally require a magic circle, ten count aria, and one minute of casting for a normal magus, and still thirty seconds with a High-Speed Aria. Caster's Divine Words allow her to shoot them in rapid succession without any preparation after simply targeting the enemy with her wand. She can fire them without pause when she has a supply of stored prana, and the result is something that resembles a bombing raid that leaves the ground scorching red.
The speed of Caster's spells cannot be exceeded by anyone because she can bring forth divine mysteries from a single word. Rin Tohsaka, someone who will eventually be among the top one hundred modern magi, is able to match her on a single spell basis by releasing magic directly from her jewels. Equal in speed, it is a battle of power without a "first move" that will end only when one runs out of energy. Caster's spells are strong enough that the only way Rin is able to nullify a single one is by utilizing years worth of prana. Even that level of magecraft is simple to Caster, as three full powered jewels from Rin capable of destroying Caster's temple and the entire Fuyuki church are easily nullified after the prana is sucked into Caster's robe.
She also uses , which is a plague wind spell that easily minces part of Shirou's chest as if it were sent through an enormous fan. She also makes use of an electrical attack and .
She also has various support spells like , which freezes the target in place by altering the pressure of the atmosphere to anchor a region of space. Everything in the surrounding is frozen, and it is potent enough to hold even Servants in place. She is able to easily cast it even while using Rain of Light, allowing her to freeze the target before destroying them. Archer and Saber are able to break free by surging their prana.
She has a constant protection over her, and she can further shield herself with , a protective spell that borrows the concept of the Argos. It is a glass-like barrier that has the same toughness as Berserker's skin. Just one of Gilgamesh's swords is able to shatter it like glass. She has a great amount of natural healing like Saber, which keeps her alive upon being skewered by the Gate of Babylon. She can also direct all of her magical energy into healing herself. If she is too damaged, she will be unable to manipulate the external energy, no matter how much is present.
She can also use a extremely strong version of Reinforcement on regular humans, greatly strengthening them and allowing them to harm spiritual bodies like Servants. This allows for Kuzuki to slay Rider and almost kill Saber due to his unique fighting style. If he were to go against Caster for some reason, the battle would come down to whoever manages to get the first strike. She cannot utilize a Reality Marble, but she can potentially construct "another world" of the same scale by precisely constructing small magecraft and large magecraft. The time and expenses required to do so would be very vast.
While she is from the Age of Gods when True Magic was common, she is incompatible with the "Five True Magics of the Modern Era", and she would be unable to learn them. She does display , a Spatial Transportation spell that is an imitation of the True Magic governing teleportation much like the teleportation granted by Command Spells. She can use it while in her territory, but she also displays the ability to teleport throughout the rest of the town as she wishes. She is able to transport Kuzuki at the same time by encircling him with her robe. She can also transport other people to her from far away, allowing her to bring Shirou to her from the mountain steps. Saber is unaffected due to her Magic Resistance.
She is able to manipulate her figure and her robe in a number of ways. She can control the prana in the air to become a dense fog that covers her entire body. This allows her to manipulate her appearance by covering herself in darkness like a mirage. Looking like a shadow that reminds Shirou of Death, she can show herself as she wishes or remain hidden from sight. She can create solid images of herself that will fade away as if she were actually killed upon being attacked. She can control them from a long distance in order to manipulate her Warriors, or she can do it while in battle to create a diversion for her attacks. Upon being skewered by Gilgamesh, it seems she has died, but she is able to hide herself in her floating cape in an attempt to escape. She can extend her cape as wings for flight, which allows her to maximize her destructive potential with the Rain of Light.
Caster has a high rank in Item Construction, allowing her to manufacture a variety of magical items. She can make Mystic Codes for combat, but she thought it would be too time consuming and instead focused on fortifying her Temple. The difference in quality between Mystic Codes forged by her and those of normal magi is like heaven and earth.Fate/complete material III Her rank makes her capable of creating healing potions that grant limited immortality, and she is capable of turning humans into formal tools to support her magic. She takes an interest in Shirou Emiya, calling him a "rare specimen" with a incomplete unique ability that is more interesting than someone who leans more towards "complete omnipotence" like Rin. She makes an "Artificial Noble Phantasm" out of him by removing his limbs and using him as a wand for Projection magecraft.Unlimited Blade Works 12th Day: Church-Palm - Artificial Noble Phantasm During the "Hazy" bad ending, he is shown to be thoughtlessly trapped in some form of container filled with water like an embryo in a test tube. He dies after the container is smashed by Rin.
Typically, Heroic Spirits of an evil nature like Caster are not eligible for participation in the Fuyuki Holy Grail Wars; however, after the Holy Grail was tainted in the third war, most of the restrictions against such spirits were lifted.
===Combat===
Caster lacks any offensive Noble Phantasms. She only has access to Rule Breaker, which is a ceremonial dagger unlikely to be able to kill even a regular human. Its main use is as an Anti-Thaumaturgy Noble Phantasm capable of dispelling and destroying any kind of magecraft. The greatest benefit it offers during the Grail War is the ability to sever the connection between an enemy Servant and Master, allowing her to take their Command Seals for her own. While she also has access to Argon Coin, she does not have the capability to utilize it. It normally would allow for the summoning of a dragon, but she lacks the necessary spells to summon Phantasmal Beasts. It has been given the status of a unusable skill during the Fifth Holy Grail War, but if she did have the proper knowledge, it would raise her standing from the weakest of the Servants to the middle ranking.
She cannot fight directly against the other Servants as a Caster. Due to the natural Magic Resistance of Saber, Lancer, and Rider, she is unable to match them in direct combat as a magus. She instead resorts to using tactics such as breaking the rules of the war to summon Assassin, creating her territory to collect souls from the town, and staying out of the fight herself so that she can observe the progress of the war before making her move. Under normal conditions she may have restrained her Master like a puppet to further her plans, but her love for Kuzuki and his apathetic view of the war allows her to make all of the decisions without resorting to such a tactic. If forced into combat, she does have confidence in her own abilities. She claims that she is stronger than anyone besides Berserker and Saber, and she states that Archer wouldn't be able to even scratch her. She is quickly proven wrong when Archer easily uses two attacks capable of killing her, one of which he even warns her to dodge.
She is not a threat in a direct confrontation like Berserker, but rather the most troublesome enemy able to worsen the situation without even showing herself. Her main goal is to prolong the time she can spend with Kuzuki, so she is mainly working hard for what comes afterward rather than forming strategies to deal with the other Servants. She uses her defensive position to have Assassin fend off the other Servants while she makes her plans. During Fate, she doesn't make a move until Berserker is defeated, and during Unlimited Blade Works, she makes a move against Shirou upon finding that he is a weak magus so that she can obtain Saber. She wishes to gain allies, so she claims that she can prepare a better Servant superior to Saber for Shirou and a magus superior to Rin as a Master for Archer.
She has a method of winning the War Holy Grail War instead of the regular fashion of destroying all seven Servants. She has grasped its true nature, and seen past the pretense that it is a only a ritual to grant the wish of one winner. She knows that it is meant to forge a path to Akasha, and that Servants are summoned only as catalysts to create that path. Even though it is impossible for other Servants, she can see the trick behind it because she is a Caster and claims that it is easy for her to win at any time.
She is prepared to do so once she has the proper tools behind her, and makes the claim that she can summon it at any moment with the help of someone with an enormous magical energy output like Saber. Upon Shirou's cooperation during the "Hazy" bad ending, she is able to obtain it and seemingly win the Holy Grail War.
Caster's natural enemy is Berserker, and she feels that she will be unable to defeat him without taking control of Saber. Even with support from Kuzuki and Assassin, her two front-line Saber-class defenders, she would only be able to damage him two or three times before her high-level magecraft would become ineffective. She is capable of supporting Assassin against him by weighing Berserker down with her magecraft, but that is only effective in repelling him from the mountain gate.
====Against humans====
In a competition against humans, it can be said that she is the most dangerous opponent capable of bringing about the most horrifying and greatest results of all the Servants summoned during the Fifth Holy Grail War. Aoko Aozaki, a user of True Magic said to be capable of battling Servants in direct combat, and Ciel, who has a prana capacity one hundred times greater than an average magus and knowledge inherited from Michael Roa Valdamjong, would be completely outmatched in a full out battle of magecraft. Bazett Fraga McRemitz, who can potentially slay Servants with Fragarach and has the capability to dodge, deflect, or nullify high thaumaturgy, would be quickly fatigued before being able to get a chance at getting an advantage in the fight. If Ciel were given cooperation from the Association and the Church, allowing her to get her hands on Gazamy, who lies in the deepest parts of the Evocationary area of the Association, and the Seventh Holy Scripture, the battle could have a different outcome.
She can easily control humans and weak Magi like Shirou, and her degree of power allows her to take control of even a magus' body from kilometers away. Due to this, she can easily control anyone in the town from her location. While another magi would have to normally infuse their own prana into the enemy to gain control, Caster is able to take hold of someone with one single cursed word. Normal practice would allow the target fight off such control by forcing the enemy prana out with their own, or by concentrating all of it to one limb so they can regain control of the other three. Caster's use of a single completed spell inserts only a "poison-like element" in one small point on their chest rather than mixing her own magical energy into their bodies. It is potent enough that it feels as if there is something wrong with their blood vessels themselves, which affects the target's entire body by taking authority over it away from the them. This makes it impossible for them to regain control over their bodies, as trying to wash away something "solid" like a completed spell with a "liquid" like prana is not possible for modern magi.
She is able to call Shirou to her all the way from the Emiya residence simply by commanding him to "Come" repeatedly with a magic-infused voice. Normally controlling him would be impossible even with his weak magic resistance, and doing from that distance is even more astonishing. It seems like a dream to him initially, but he eventually realizes that his limbs aren't moving under his own will. Without any resistance, he walks all the way to the temple in a daze while his limbs are manipulated. Even once fully conscious, he is unable to stop himself, and he is unable to even scream due to his throat being frozen. The only way for him to regain control is for her to release him from the spell or to receive outside help. Once given control, she can skew their senses, distorting the vision or rendering them blind. She can eliminate their bodies or minds in a matter of seconds, which allows her to destroy Shirou's mind while keeping his body for her own use. She is capable of churning his insides from a simple whim, and then completely stops his senses and ceases his mind.
She can also easily turn humans into "dolls" for her own use. Using "artificial Command Spells", she instills her control upon all the people at Ryuudou Temple. They become "things" that execute a single command when they find someone that breaks one of the "three rules" she has established. Upon asking Issei Ryuudou about Caster, he immediately blacks out and slashes at Shirou's stomach upon getting back up. Caster is able to speak through him, and mentions that the implanted order only functions when someone inquires about her. She is also able to manipulate them further, which allows her to have Issei kill himself by stabbing his own neck.
===Dragon Tooth Warriors===
 are familiar constructs created using a monster's body as a catalyst. They are manufactured and bound by dragons' teeth by utilizing her Item Contruction and seem more like golems than automatons. Ilya calls them cheap, and Saber mentions that their quality is low. They are brought about by scattering dragon fangs over the ground, and they receive the prana of dragons and knowledge of the earth. They use a variety of different weapons wielded with smooth, mechanical movements that provide wasteless, accurate attacks. The attacks, while accurate, are not refined and do not cause a sense of fear in Shirou like Saber's attacks when they spar. They all move in loose movements and attack in the same way.
They are weak enough that Shirou can defeat one in direct combat with a reinforced wooden sword. Their main benefit comes from their numbers that can quickly increase as Caster pleases. Even one hundred of the fake dragon warriors would still be no match for Saber, but they are still numerous enough that they can keep her busy while attempting to destroy all of them. She can easily destroy them quickly enough that the scattered pieces of bones make it look like there is a snowstorm, but she wishes to use Excalibur on them due to there being too many to fend off at the time. There are enough that they can surround the entire Emiya household and appear to be nearly infinite as more are brought forth when they are destroyed. They continually destroy the area around them with each attack as they try to slay their targets.
===Master===
She is capable of easily breaking the rules of the Holy Grail War by slaying the original Master who would have summoned Assassin and summoning a Servant of her own. He is an Assassin summoned by an improper Master, so someone other than the proper Assassin, one of the Hassan-i-Sabbah, was summoned. Spirits cannot form proper contracts with other spirits, so only her knowledge as a magus allowed her to form the connection. The results are poorer and more ineffective than under conventional circumstances, so she summons a fictional hero who is based off of a wraith rather than a true Heroic Spirit.
She had something similar to a Command Spell. Though, as a fake Master with a fake Servant, it wasn’t something as powerful as a true Command Spell. While she may not originally have received any Command Spells, Caster may have skillfully borrowed the power of the Greater Grail to forge herself an imitation. As with other Masters, she is able to forcibly remove Command Spells from a Master by severing their arm and all the nerves in their bodies in order to transplant the Spells and become the Master of their Servant. If she can come into contact with the Servant, Rule Breaker allows her to obtain the Command Spells much more easily. Through those methods, she can take control of as many Servants as she wishes due to siphoning energy directly from the land, allowing her to her to act as the Master of Saber, Archer, and Assassin simultaneously. 
She thinks Saber is too valuable to disappear, so she make it her main goal to obtain her. She is unlucky with Saber, as her Magic Resistance is great enough that it takes two Command Spells to immediately force her to do any task that she doesn't wish to follow. Caster doesn't wish to waste them, so she is forced to wait a great deal of time for Saber to finally reach the breaking point from the initial command.
===Temple===
Caster has a high rank in Territory Creation, allowing her to use the Ryuudouji Temple and surrounding mountain as her Temple. It is a very suitable place for her, as it is the greatest spiritual land of Fuyuki City that holds many of the leylines of the area. It is unfavorable for Servants and it allows her to easily draw energy from the land and the citizens of the city in order to provide her with a nearly limitless amount of prana. She compares it to having one thousand Masters, and she has enough energy that she claims to be able to have Saber use Excalibur as many times as she wants. She has placed a magical string throughout the town for this purpose, and she has taken control of the leyline with sacrifices. It is also considered on of the four main areas where the ritual of advent of the Holy Grail can take place, which guarantees her the ability to summon the Grail once the conditions are met. It also provides for the greatest defense in the city due to a strong barrier that was likely set by those who first constructed the temple.
The entire mountain is surrounded by a powerful Bounded Field, , that rejects unnatural spirits that set foot around the area. Servants attempting to cross it will have their powers reduced, and the effects of Noble Phantasms are also greatly diminished. Caster has also set up her own to greatly diminish the effects of outside magecraft as well. Humans and magi are unaffected, allowing them to enter anywhere on the mountain without any problems. The effects of the Bounded Field only affect those that directly cross the boundary line, and it has no affect on those directly inside the Bounded Field itself. Once inside the temple, it acts as a suitable place to sustain spiritual entities, which is one of the reasons Caster managed to avoid disappearing before establishing a contract with Kuzuki.
It is impossible to fully close off the area with the Bounded Field, as the leylines require a connecting point with the outer world in order keep them from being halted and rendered unusable. The only weakness in the barrier is the temple's front gate and the path leading to it up the mountain, which acts as the focal point of the leylines. This allows for Servants to enter through the gate undiminished as long as they follow the main path up the mountain. Caster has covered this weakness by placing Assassin there, and due to the terrain advantage and his own skill, he manages to repel all five enemy Servants. This specific location was chosen due a policy of the temple’s monks in which they do not refuse entrance to anyone who walks through their front door.
The method she uses to take the energy is through a witches potion that destroys love. It takes their magical energy and renders men impotent. It leaves behind the smell of a rotten plant, and it can render a large number of people in various areas in comas. Rin finds fifty people, most of which are men, who have thrown up blood and fallen unconscious at once. The large number of people placed into comas is attributed to gas leaks causing people to pass out after running out of oxygen, which have been ongoing since before the formal start of the Holy Grail War. When she first began to collect the energy, it was hard for her to hold back because each individual only has a small amount. The result was that she ended up taking too much at a time, but she likes to keep her victims alive so that she can take every bit of prana as possible. She eventually managed to begin collecting it much better, allowing her take energy from hundreds of people at one time. The swirl of preserved magical energy, pieces of people, is collected within the land and used by Caster. Shirou sees that it is made of more than a thousand souls that stain the entire mountain in energy.
==References==