Illyasviel von Einzbern

Illyasviel von Einzbern is a heroine from Fate/stay night. Often referred to as Ilya, she is a German aristocrat who participates as a competitor in the fifth Holy Grail War. She is the daughter of Kiritsugu Emiya and Irisviel von Einzbern, both whom participated in the fourth Holy Grail War with Kiritsugu as the master of the Servant Saber.

Illya travels to Japan to participate in the Fifth Holy Grail War as the master of Berserker. During the initial stages of the war, she lives in the Einzbern Castle on the outskirts of Fuyuki City, accompanied only by her Servant and two maids. While she possesses an angelic appearance with a playful personality and is usually seen smiling, Illya has unsurpassed potential as a Master. She asks those she feels comfortable around to call her "Ilya".

Ilya is the main character of an alternate universe spin-off manga entitled Fate/kaleid liner PRISMA☆ILLYA.

Appearance
Much like the characteristics of all Einzbern homunculi, Illyasviel has crimson eyes and long silver hair. Due to her white-blonde hair and red eyes, she is often considered an albino by fans. Similar to her mother, Irisviel, Illya also bears a genetic resemblance to her ancestor, Justeaze Lizrich von Einzbern, who was responsible for the formation of the core of the Holy Grail. She wears a collared, purple long-sleeved shirt with a light purple scarf to match, a long white skirt and purple boots.

Though Illya was born through natural means, her body has been heavily modified before and after her birth to maximize the magical circuits in her body, making her the ultimate homunculus and a refined vessel for the Holy Grail. As a result of the modifications to her body, her physical body develops slowly and her father, Kiritsugu Emiya, correctly assesses that her physical body will not develop secondary sexual characteristics. By the time she is eight years old, Kiritsugu notes that even his Thompson Contender is heavier than Illya is. A decade later, when Illya meets Shirou Emiya, she still looks as though she's a young girl rather than a young woman.

Personality
Illya is cheerful and outgoing, being up-beat and generally having a positive attitude. Possessing a friendly demeanour, she is easy to talk to and tends to be playful and mischievous. Deep inside, Illya is lonely, as she has no friends her own age to play with and is often stuck inside the Einzbern castle honing her magecraft. When she first meets Shirou, she sees him as something of an older brother. Though he is distrustful of her at first, he comes to like Illya, seeing her as a little sister.

In reality, she is the daughter of Shirou's adoptive father, Kiritsugu Emiya, and Irisviel von Einzbern. This would make her his adoptive sister.

It can be said that Illya gets her outward personality from her mother. Like her mother, she is kind and childlike. However, she also has a measure of her father in her, as she can be callous and kill others without remorse.