Chloe von Einzbern

Chloe von Einzbern (クロエ・フォン・アインツベルン), also known as Kuro (クロ), is a twin existence formed from Illya's original self in Fate/kaleid liner PRISMA☆ILLYA. She appears as Archer (アーチャー), an Archer-class Servant able to be summoned by the Protagonist in the Grand Orders of Fate/Grand Order.

Background
Ilya was born to act as the key of the Holy Grail War system of Fuyuki, but it was never actualized in the Fate/kaleid liner world. Her parents, Kiritsugu Emiya and Irisviel von Einzbern, decided to abandon the ritual by Irisviel's choice, but Ilya still had the knowledge granted to her to act out her purpose. She had been continually tuned during her first few months of life, given the ability to understand words and different types of knowledge. Irisviel believed that an eight month old existence could not outweigh the thousand year dream of the Einzberns, so she sealed Ilya's faculties, knowledge, and memories in order to allow her to live as a normal girl.

Irisviel miscalculated the process, so the sealed memories grew up inside Ilya and eventually became a second personality. Due to Ilya's ability to "grant wishes" as the vessel of the Grail leaking from the seal, this personality became powerful enough to harness the Archer Class Card and create a body for itself, becoming Kuro. She refers to herself as Illyasviel von Einzbern even after being separated, but has her name changed to avoid confusion.

Personality
Kuro is generally much calmer and more nonchalant than Illya. She is devious and manipulative, picking up on subtleties about people and using them to her advantage, and she can be very brazen and unrestrained in her actions. She has experienced all of the same events as Illya, allowing her to recall events before she manifested.

Kuro is deeply bitter as a result of having been sealed, both towards her parents for sealing her, and toward Illya for wishing to be 'normal'. She believes Illya is indirectly wishing for her, the manifestation of her past as part of a Magus clan, to not exist. She places pride in the reason she was born, and wishes to follow it if she can. The idea of being called a second hand clone infuriates her, for the name 'Illya' originally belongs to her.

Kuro easily gets into conflicts with Illya, fighting over any miniscule insult. Funnily, when Illya is unable to stop Kuro in some of these conflicts, she uses the effect of a curse to inflict pain on Kuro by hurting herself. Due to Kuro's appearance and her tendency to drain energy through kissing, it certain comedic situations and misunderstandings.

Kuro also shares Illya's affection towards their brother. However, she is more forthright with Shirou, allowing herself to express the feelings Illya has not been able to express. Kuro became jubilant when learning that the identity of the Archer Class Card, that was used to manifest her body, is EMIYA.

PRISMA☆ILLYA
Kuro's first sign of existence comes during the battle with Saber after the defeat of Illya, Miyu, Rin, and Luvia. Filled with despair upon seeing their last hope wiped out by Excalibur, the seal, a metaphorical lock inside Illya, comes undone, and she, who should know little about magic, displays a large amount of magical energy far beyond that of a normal person under the threat of death. Illya mostly loses consciousness, allowing an emotionless personality to emerge that quickly realizes the best way to gain power is from the Class Card. She takes the Archer Card and utilizes the Install ability for the first time. She emotionlessly defeats Saber by overpowering her with a projected Excalibur, returning to normal without any memory of the events, while the lock returns to normal.

The power is displayed again against the Assassins, when the team get raided and Illya is disabled. Though the team survive the raid, she is distressed by the power, because her attack also entangled her friends. Losing self-confidence, she attempt to forget everything related to magic and return to her normal life. Irisviel, the girl's mother who happen to come back home for the first time since the beginning of the story, notices her distress and talks to her. She mentions that the seal has been drained of power after ten years of weakening and two times of breaking, and that she did not expect it to loosen so early. She refuses to elaborate more on the topic, simply telling her that the power is neither good or evil and that, as a part of her, it is her will to use it that is the most important. Illya regains her confidence, helping Miyu defeat Berserker by utilizing the power for a third time and seemingly end the conflicts.

PRISMA☆ILLYA 2wei!
While attempting to fix the Earth's Pulse that has been disrupted by the Class Cards, a reflux causes the cavern to begin to collapse. Utilizing the power for the fourth time to Install the Archer Class Card, Ilya protects them from the falling rocks, but feels a strange disruption. After everything has cleared, they are all shocked to find two Ilya next to each other and the Archer Class Card missing. The duplicate, with the exception of dark skin and the Archer outfit, quickly runs away during the confusion.

Kuro makes various attempts on Ilya's life the next day, stating that they cannot both freely exist. Ilya and Miyu try to fight her, but Ilya has lost most of her power and Miyu is dispatched by having her energy drained. Ilya manages to make Kuro leave by surprising her with an attack. Rin decides to deal with the problem by catching Kuro, utilizing Ilya as bait. She still arrives even though the trap is obvious, and manages to foil their attempts. She easily dispatches Rin, Luvia, and Miyu, but gets tricked by Ilya into stepping into the original trap that seals her magic.

Upon interrogation, she simply states that her only goal is to kill Ilya, while refusing to divulge any new information. Rin decides to nickname her Kuro to avoid confusion between the two Ilyas, and utilizes Ilya's blood to create a seal on her. It makes it so that she shares all sensations with Ilya, including injuries and pain. Unable to fulfill her original goal, she uses her appearance to try to sabotage Ilya's relationships, her normal life, because said normal life is what she would rather have than magic, essentially denying Kuro's existence.

Appearing at school, she drains several people, causing Ilya grief. They are exposed afterward, causing Kuro to introduce herself as Ilya's who will be transferring to the school the next week. She claims she wishes to try living a normal life, so they allow it as long as she does not harm anyone and acts out the role of Ilya's cousin. She interacts with the students the following week, and plays a dodge ball against those whose first kisses she stole from them with the losing team acting as servants to the winners. Ruby believes her true goal is to take Ilya's place, so Ilya duels her to protect her normal life.

The fight results in a double knockout after Kuro injures Ilya, and herself, after being insulted. They discuss the missing Archer Card later on, and ask Ilya about her motivation to fight, which is to return to her normal life. This angers Kuro, causing he to ask what becomes of her in that normal life, and reveals the location of the Archer Card inside her. She then decides to end the "farce", using a powerful attack to escape. She leaves a message for Miyu the next day, asking her to come alone.

She eventually comes to terms with her anger after Ilya finally accepts her, only to begin breaking down shortly after. Although on the verge of death, Ilya is able to convince her to fight for her new life, making her admit that what she wants most is not to be a Magus, nor to kill anyone, nor even to be accepted: most of all, she just wants the chance to live. This admission is enough for her powers as an incomplete Grail to activate, granting her wish to live and stabilizing her body. She is then formally adopted into the extended Einzbern family, being introduced to Shirou as Ilya's cousin Chloe von Einzbern

PRISMA☆ILLYA 3rei!
After being transferred to another world, she is first seen with Bazett while meeting with Ilya, Tanaka, and Gilgamesh. Kuro then had a fight with Ilya on the rooftop, but soon was overpowered by the power of Saber class card and because she was running out of magical energy.

She, along with Bazett, later helps Ilya and Gil free Rin and Luvia from the Ainsworth's control, and she later helps the now-freed Miyuverse! Shirou fight off Angelica at the Ainsworth castle and delay the plans of Julian Ainsworth, and force him to retreat for the time being.

Magical Girl Travel Diaries ~Prisma Corps~
She was possessed by the Testament and calls herself as the First Lady.

Abilities
Kuro originally did not know the identity of the Heroic Spirit whose form she has borrowed, but later learned of it after meeting Miyu's brother. She has only inherited the fighting skills that he refined. She wields her formidable combat powers with reckless abandon. Rin saw this as a threat, and inflicted on Kuro a curse of shared pain perception. Kuro’s shared pain with Illya was meant to deter her from targeting her twin, but the trifling curse meant nothing to the little devil.

Having received most of Ilya's magical power, Kuro is extremely powerful, capable of using all of the Archer class' abilities to a high degree, and easily able to overpower magical girls and even Miyu's Saber class change. She has physical strength equal to that of a magical girl, allowing her to damage a wall with a towel. She is much more analytical than Ilya, allowing her to read her opponent's strategy. She can utilize basic magic like a ball of magical energy that breaks apart the ground and reversing binding magic on the caster.

Kuro also possesses the ability to teleport as shown when fighting Angelica with Shirou (Miyu's brother). The range of this is still unknown.

She generally fights with Kanshou and Bakuya in close combat, and makes use of metastasis and Projection to create other Noble Phantasms. She can create mundane objects like a chair, or more powerful objects like Fake Nine Lives, Berserker's axe-sword, using it as a shield in front of her and running at the opponent. She fires Caladbolg II as an arrow.

She has the ability to drain people of their natural energy through the act of kissing, leaving them weakened and unable to act. She has to replenish herself often, but normal people are not suitable enough for her needs. While draining several normal people still leaves her weakened, magi like Rin and Luvia or someone powerful like Miyu can provide her with enough energy alone.

She has been given a seal formed from Ilya's blood that connects replicates all physical sensations caused to Ilya onto her. It replicates all injuries caused to Ilya of them, no matter how slight the sensation, and reproduces even effects like having a cheek pulled. If Ilya, her "master", were to die, the same would happen to her.