A character who first appears in the manga Fate/kaleid liner Prisma Illya 2wei!, and its anime adaptation. She is a dark skinned version of Illyasviel von Einzbern, and is initially referred to by the cast as "Black Illya" (黒イリヤ Kuro Illya). As she also refers to herself as Illyasviel von Einzbern she was later given the name "Kuro" (クロ), from "Black" (黒 Kuro), to differentiate her from the regular Illya. She herself later expanded on that name when she need to have a full name and called herself "Chloe von Einzbern" (クロエ・フォン・アインツベルン, Kuroe is how the Japanese write Chloe). Throughout the series though she sticks to predominately using the name "Kuro" (クロ), and is referred to as such by herself and the rest of the cast.
When Illya's parents choose to abandon the Holy Grail War, they went and sealed Illya's consciousness and memories of the first few months of her life, as she had been trained and tuned for the ritual, preventing her from living a normal life. This sealed consciousness, though, eventually became a secondary personality and was able to split off from Illya and obtain her own body via the Archer Class Card.
Chloe is also a servant under the Archer designation in Fate/Grand Order, wielding Kanshou and Bakuya with great skill.