James Ratri

William Minerva is the owner of all the books that are currently available in the library of the Grace Field House.

Phil discovered that all the books contain some kind of secret message in them. Telling the children to run from the house, because there is danger

William Minerva also left a pen behind for Sister Krone with the initials WM on it, implying that the initials are his.

William Minerva seems to be on the children's side but at the same time, he seems to be affiliated with the Demons and humans outside the Grace Field House. It is currently unknown why he left the books with the secret message in them behind and why he left a pen behind for Sister Krone.