She takes her duties as a Magical Girl very seriously and is initially dismissive of Illya's abilities, but gradually warms up to Illya. She comes to value Illya's friendship greatly and is highly protective of her.
Miyu is the complete Holy Grail from the world in which the Class Cards originated. Her brother is that world's version of Shirou. Brought to the main world through unknown means, she was taken in by Luvia in her search to rival Ilya and Rin's partnership.
Fate/Kaleid Liner Prisma IllyaEdit
Miyu takes on the Edelfelt name after being taken in by Luvia. She lives in Luvia's mansion and acts as her maid to earn her keep. She uses Ruby's sister Kaleidostick, Sapphire, in order to transform, and she initially has a much better understanding of her abilities than Ilya. She takes her role very seriously and treats Ilya as a bothersome rival, though they eventually become close friends. She later gains the ability to use the Saber class card to embody the Heroic Spirit after seeing Ilya perform it.
Later it was revealed by Gilgamesh that she comes from a parallel world and she is a princess.