Spirit of Intellect
A Spirit of intellect is a disembodied Spirit of great Thaumaturgical Knowledge. They usually inhabit human skulls, but are capable of inhabiting living human beings. They are capable of keeping their presence hidden or of making it well known.
One such spirit has become a Genius Loci at the Ars Medievalis in the deep Vault. In 1936, Agostino Selletti inadvertently allowed himself to be possessed by this spirit, and freed him from the Library.
The Intellect desired to inhabit the body of the Soul Stealer that the local SAVE office was fighting at the time. It was unsuccessful and was apparently destroyed during the battle. A Spirit of Intellect takes on the demeanor of the Thaumaturge it is dealing with. They become an aligned reflection of the means, methods and morals of the thaumaturge they are working with.
The knowledge contained within such a Spirit is seemingly limitless.