Gillian

Gillian, often referred to as "Sister Gillian," by the Crusaders and "G" by the UTE crew, is a mysterious entity whose motives are unclear. She is the original owner of the book, and may have left it for the boys to find as a warning.

Powers
She seems to have some sort of power, such as being to teleport. She once entered Jaxon's room one night to give him the leather jacket, and in the same night left a package on William's doorstep.

Relationship with The Crusaders
She may have at one time been a member of the Crusaders, as the book containing information about the Crusaders. She may or may not have been the person to upload INTRUSION.