Servant Card

What Illya and the rest call “Class Cards.”
There are two usable kinds, the “Limited Deployment” that allows to manifest the symbolic armaments of Heroic Spirits, Noble Phantasms, and the “Fantasy Summon” that possesses the own body with a fragment of their power.
They seem to make use of the technology of displacement magecraft, so at the time of Limited Deployment a Code or similar of a certain high level is necessary to become the source of displacement. It seems that the Dolls, whose body itself consists of a special puppet, can perform a Limited Deployment using a part of their body.
As a general rule one Heroic Spirit corresponds to one Card. A Card that isn’t connected to any Heroic Spirit is called a “Waste Card,” and becomes a throwaway weapon.
An outstanding device that can access to the Throne of Heroes reached by historical heroes… is what they are, but the access process feels awfully suspicious.

PRISMA material/petit: Encyclopedia of Prisma Illya MOVIE