Irisviel is the main heroine of the story and Kiritsugu's wife. She is a homunculus prototype created by the Einzbern family with the idea of giving birth to an ultimate homunculus. Like many of the Einzberns, she is skilled in alchemy. Irisviel serves as Saber's proxy Master, since Kiritsugu believes that he and Saber are incompatible. Due to possessing the inborn knowledge and reasoning of homunculi, hindsights gleaned from the 1000 years of history of the Einzbern as well only having nine years of life-experience, she has both the elegance of a lady and the innocence of a child. Her true purpose in the War is as the vessel of the Holy Grail itself.