Doctor Gill was a character in one of the stories, featured in the Spook's Bestiary.
In his bestiary, John Gregory describes Gill as a "liberal and intelligent man."
He goes on to say: "who understood the part we [Spooks] played in the County by the servants of the dark and routinely sought my advice."
Gregory and Gill therefore had a professional relationship, and seemed to collaborate often.
Gill had a career, working as a doctor.
As a doctor, he came across some elements of his job, which causes him to seek the advice of John Gregory, a local Spook.
Emily Jane Hudson
At one point in his career, he ventured to the village Ormskirk, to attend to Emily Jane Hudson. Like many other doctors before him, Gill was unable to save Hudson.
Gill observed that Emily's face, shoulder and neck were terribly swollen, but there was not an ounce of fat visible on her. It looked as if someone had "forced something into the space between skin and flesh." To support this theory, there were two large marks on her neck and then same on each shoulder.
This incident was recorded in John Gregory's Bestiary, as one of three Mysterious Deaths in the County.