Caster’s True Name is Illyasviel Emiya, known in life by many as the Second Magus Killer, Blue Mirror, and Miss Lily. As with other members of the Emiya-Einzbern family inscribed in the Throne of Heroes (like EMIYA [Archer], EMIYA [Assassin], and Justeaze [Ruler]), her story is deeply entwined with the Holy Grail War.
Born in Germany in 1986 to Kiritsugu Emiya and Irisviel von Einzbern, she was to be the incarnation, the human sacrifice which contained the Lesser Grail for the 5th Holy Grail War should it ever have begun. While raised by Kiritsugu and Irisviel during her first 8 years of living, she was abruptly sent back to Germany in the midst of the chaos of the 4th Holy Grail War, in which Irisviel was sacrificed to become the Lesser Grail, while Kiritsugu Emiya fought a bitter battle with Kirei Kotomine, ending in a draw which coincided with the destruction of much of Shinto, Fuyuki.
The patriarch of the Einzbern family, Jubastacheit von Einzbern, sought to ‘train’ Illyasviel, by getting her to believe that Kiritsugu had abandoned her and killed her mother, then using her to get revenge on Kiritsugu Emiya for destroying the Grail and betraying the Einzberns. However, in the aftermath of the Fuyuki Fire, Kiritsugu isolated himself from the world, and began to prepare a mission to retrieve Illyasviel and save her from the Einzberns. In the year between the fire and her retrieval, Illyasviel’s conviction and belief that Kiritsugu would save her let her resist the callings of Angra Mainyu, appearing to her as a mirage in the form of Irisviel.
While Kiritsugu saved Illyasviel, it came at a great cost. Kiritsugu’s body was rapidly drained, stretching the sheath of King Arthur, Avalon, and its healing to its meagre limits. Angra Mainyu decided to spare Kiritsugu, but burnt down the Einzbern mansion in Germany in a manner similar to the Fuyuki Fire. And Illyasviel, in the middle of all of this, had her perception of the world as a whole shifted and distorted, as the fires blazed around her. Unbeknownst to her, this was the moment her Reality Marble actualized.
In the interim time between the 4th and 5th Holy Grail Wars, from 1995-2004, Illyasviel lived in Fuyuki. Kiritsugu was able to teach Illyasviel all he could before he died in 1999, and she adapted accordingly into the Fuyuki environment, shedding the Einzbern name for the Emiya one. She met Rin Tohsaka, a fellow magus, who, unaware of Illyasviel’s true heritage, became friends.
At the beginning of her Grail War, she was identical in every way to Illyasviel Emiya: both of them were shy, quiet, yet social at the same time given the right circumstances. However, when the HGW began to take a turn for the worst, with her best friend Rin being killed by Berserker, Illya began to question herself. “How can I be a superhero when I can’t even save the closest ones to me?”, she asked. Because of this, when she and the Miyu of her world allied and holed up in the abandoned Einzbern castle to hide from Sakura’s rampage across Fuyuki after Rin had been slain by Sakura and her Servant stolen, the two began to form a romantic relationship, formed upon their mutual attraction to each other and their similar ideals related to heroism.
Thanks to their inactivity, however, Sakura was allowed to roam unrestricted, provided that she did not reveal the existence of magecraft by Kirei. Nearly all of the remaining Masters and Servants were killed, with some of the Servants becoming corrupted and reborn by Sakura’s ‘Servant’ using her skill in Imaginary Numbers to warp the Servants into a mold more befitting Sakura’s needs. This included Archer Origin (known as Hercules in life) and Berserker (her own Servant, known as Cu Chulainn, who lost all remaining sanity). Thanks to Kirei tipping her off, Sakura planned to storm the Einzbern mansion.
Doing so with Archer Origin and Berserker in tow, Sakura attacked the mansion. Berserker and Archer faced off against Saber, while Illya and Miyu faced Sakura. While Berserker proved to be an immense challenge, Archer stayed out of the fight until Berserker had been slain by Saber in personal combat. Then, Archer utilized his Noble Phantasm Nine Lives to attack Saber, whose sustained damage ended up killing her, but not before Saber launched Excalibur to vanquish Archer as Nine Lives moved across the space. Sakura, seeing that she was disadvantaged, retreated.
In the aftermath of the battle, Miyu was mortally wounded, stabbed by Black Keys in numerous places while bleeding out. However, in an act of desperation, Illya implanted Avalon in Miyu, which, while effective only for a few minutes due to Saber using her sheer willpower to stay alive and maintain a connection of mana between her and Avalon, helped to heal her injuries before Saber faded away.
Illya proceeded to go to Kirei Kotomine, the Overseer of the Holy Grail War, and ask for amnesty, after her Servant has been defeated. Kirei then unexpectedly stated that he will offer the temporary use of a Servant, if she kills Sakura. He stated that because of Sakura’s actions, she has crossed the ‘line’ in regards to the War’s regulations. Illya, while naturally resistant to the idea, realized that she has no Servant. Kirei stated that if she wins, then she would win the War, as all other Masters have been defeated. By doing so, then she will have achieved her dream. Then, he asked a simple question to her:
“Do you want to be a hero of justice? If so, then return here tonight with the news of Sakura Kotomine’s disappearance.”
When Illya heard this, her mind shifted completely. While something felt wrong just interacting with Kirei, she realized that this was one of the many sacrifices that must be made to become a hero of justice, to protect the one she loves.
“I’ll take it.”
And so, she went forwards, taking Gilgamesh along with her to take down Sakura once and for all.
The confrontation took place at Ryuudou Temple’s courtyard, where Sakura attempted to use her status as the primary Grail conduit to unleash the Grail. With Gilgamesh’s aid, Illya managed to get to Sakura before she could complete the ritual. The two engaged in combat, with Sakura’s injuries greatly hindering her, while Illya relentlessly attacked her, holding sheer fury for the fact that Sakura tried to kill Miyu. Meanwhile, Gilgamesh took out many of the Grail’s shadows, but thanks to his sheer arrogance, was overtaken by the shadows, similar to a potential scenario down a different road. However, the intervention of Kirei allowed for Sakura to be distracted long enough for Illya to inadvertently draw upon her Reality Marble, and Project a sword from the visions she had of Caliburn. As the replica fired its beam, Sakura and the shadows were completely torn apart by the sheer mana, turning into vaporized nothing as the light faded from the dead of night.
Illya, stumbling and unaware of her surroundings, due to the insane mana cost of creating the Projection, came across Kirei as she attempted to exit. Kirei was surprised, stating that he expected her to try and back out. Illya, in her ragged state of mind, was confronted with Kirei’s words: “Rejoice, girl. You have won the Holy Grail War, just as with Kiritsugu Emiya.” As he leaves, she collapsed to her knees, tears in her eyes, with bile and acid lining her throat.
“You have become a superhero.”
In that moment, Illya turned her mind to steel.
She and Miyu would remain in contact shortly after the damage caused by Sakura had been covered up and repaired by the Church and Magic Assocation. However, both of them would grow distant, as Miyu became disgusted by Illya’s methods while conducting missions for the Association. This all came to a head about 10 years after the end of the 5th Holy Grail War, when Miyu disappeared without a trace from their joint residence in England. Without moral support to maintain a facade of still being relatively human, Illya truly embraced becoming a superhero.
This caused her to steel her emotions. Unlike the Shirou Emiya of another world, who used his dream to guide him, Illya went down the route of Kiritsugu Emiya, unfettered as she strove to be a ‘superhero’. Her definition of this was wildly different from Kiritsugu’s, as she does it all for the sake of ‘protecting’ Miyu. This came in the form of assassination of dangerous mages, Dead Apostles, and other beings similar to Angra Mainyu. However, the sheer brutality and cruelty of reality in relation to her ideal wore it down to the point of turning her into a machine, an embodiment of justice. As her life progressed, she began to lose her memories, of lighter times spent with her surrogate older sister, of interacting with Rin in Fuyuki and Luvia in London, and even that of Miyu, in their days spent in isolation during the War. However, the emptyness that filled her also allowed for her to devote all of her spare time to research into her father’s magecraft. As she progressed, and two decades passed, she made a breakthrough into Innate Time Control, allowing for her to construct a Temporal Bounded Field for the first time. This was noticed by the Magic Association, who placed a Sealing Designation on her.
However, during this time, Illya also expanded her horizons in regards to Innate Time Control, eventually reaching a point where she could momentarily stop time in a given space completely without Gaia’s interference inside the space. Keeping this hidden from the Association for the time, she embraced her known abilities in time manipulation as the daughter of Kiritsugu Emiya, and the title of the Second Magus Killer. However, her barely remaining ideal still remained, as the years passed.
30 years after the end of the 5th Holy Grail War, Illya went on her final assigned mission. Located in Old Fuyuki, a worn-down, ghetto-esque area located where Ryuudou Temple used to be, she was assigned to assassinate a group of rogue mages who had taken a hundred prisoners hostage inside an abandoned residential area, most notably, a relative of an Association lord who had been kidnapped.
Arriving there, she completely obliterated the outlaws, whose shoddy arcane magic was utterly useless against Illya’s uses of Innate Time Control. However, as she progressed through the lair, she encountered more and more of the hostages killed in increasingly grotesque ways. In her mind of steel, however, she took the visions as they came, and kept moving through the lair.
Finally, she reached the basement. Inside, the leader of the mages, an insane madman, desperately tried to stall Illya. As he talked, she slowly took a step forward, gathering mana to create a lance entirely made of mana. He retreated into a deeper chamber, locking the doors magnetically, to which Illya responded by cutting straight through the doors with her Projection. Finally, he pulled out an incredibly long rope, and revealed two people, both with their necks loosely tied with the rope. Both were abused and tortured, almost the point of death, and Illya recognized one of them immediately: the lord’s relative. However, something about the wide, frightened eyes of the other seemed familiar, eerily so. When he gave Illya chance to free one, in exchange for the other’s death, if she stated her decision within 30 seconds, she remained quiet. A part of her suddenly recognized the second person, and screamed for Illya to free her. However, Illya stays still, as both of them, mouths muffled, screamed.
Suddenly, in the last second, Illya’s mind of steel shattered. The eyes of the second woman, she realized and recognized their eye color, their face, and all of their body.
She yelled, and as the mages’ leader gleefully tears off the vocal restraints of the dying Miyu Aoki, she attempted to activate Time Alteration.
Only, as she moved, she could only hear Miyu’s hoarse voice barely breathe:
“Go to hell with your precious ideals.”
She was too late. The noose came up, and both Miyu and the Association lord’s relative asphyxiated, as Illya watched in stunned disbelief.
Tears began to stream, as she began to break down. As the mages’ leader chortled, he was decapitated by Illya’s Projection of Tōsaka, before she collapsed into a pool of sorrow, anger, and realization.
It was at this point that she changed for the last time. She fell off the reported map completely, rumored to have isolated herself inside the ‘Phantom Citadel’ created out of the abandoned Einzbern castle just outside of Fuyuki, which oddly enough, was unable to be detected by normal means, both magical and non-magical. She gained a sense of zen, a realization that her ideals failed her, something that other members of the Emiya family in other worlds failed to accomplish in their lifetimes. Because of her previous accomplishments, however, as an assassin in both the moonlit and normal world, she possesses enormous reputation, enough to have her name known throughout the entire world. Officially marked as having gone missing the day she arrived in Fuyuki, she ended up having her status as a Sealing Designate increased, causing the Association to actively pursue her. During this time, Illya discovered a method through going further with the Emiya family magics and her father’s applications: she found a connection to the Root. By using the Emiya family crest as a direct conduit to the Root in conjunction with her techniques, she discovered her magnum opus, the culmination of her family’s search for the Root: the complete stoppage of time in the entire World, utilizing a flow of power from the Root itself to ‘add’ time to the timeline and separate herself from the rest of the World, allowing her to move through paused time.
However, this breakthrough, to which the Association notices, was enough to order the assassination of Illya. By the time Enforcers came to the mansion, however, Illya had committed suicide by poison, having transferred her books and knowledge to possession of a friend who was part of the Church, and having also set up a series of traps inside her citadel, where if her Magic Crest was touched in any way, the mansion would be blown sky-high by numerous mana explosions. As she took the poison, she saw the sunrise coming over the landscape, and smiled. As she began to waver, she saw her inner world come to life around her, the snow and frost biting against her. Despite this, she accepted her fate, as she created a Wish-Imbued Projection of Avalon, and held onto it as she collapsed, dying with a smile on her face.
Originally Posted by Dullahan
