Name: Heaven's Feel (AKA the Golden Grail)
Territory: Soul Materialization
User: Unknown, (Probably Lizleihi Justica von Einzbern)
General: The lost magic of the Einzbern. Not the creation of a replica from a soul in the past, but the making of a high-dimensional (planar) being that can cause interference in the material world on its own while being a mental body.
The turning of a soul into a living being to bring it onto the next step as a life form. Resurrection of the soul. A soul materialized by the third can and will reshape itself into the "form of the soul" completely if put in a vessel with similar enough properties as a human being based on the "genes from the soul", the "organic" soul itself is moving the body by remote-control. Of course, putting that soul back into the body, while getting the benefits of reenacting the soul through the body, means it's also going to be anchored into it. Meaning that you will get sick, bleed, age, and die like a normal human being.
Notes: Servant summoning uses imperfect pieces of the 3rd. Giving form to a soul. The ideal goal is to make the physical body unnecessary to living. A living ghost. The Einzbern Dress of Heaven does enable materialization of the soul independent of the Greater Grail, but only for several seconds, and is used for transmission of a soul into another object. A secret among secrets even within the Association.