Magical artifacts created to allow for the summoning of heroic spirits similar to Servants that instead allows the user to borrow their powers & abilities. They serve as a major plot point in Fate/kaleid liner Prisma Illya.
They have two main functions, Include and Install. Inclusion allows for the wielder to materialize a weapon or Noble Phantasm belonging to the heroic spirit, while installing manifests the servant directly into the user's body, including their appearance.
The cards can also manifest independently as blackened Servants, acting as weaker versions of their own selves.
