Mary Keay is a recurring character in The Magnus Archives. She is not exclusively loyal to any of the Entities, but she does use their power when it suits her. She is the mother of Gerard Keay and widow of Eric Delano.
Mary Keay is described as a very old woman. Prior to her first death, she had a full head of hair and no tattoos, but, after her death, she is described as having a clean-shaven head and skin completely covered in "closely written words" in an unknown language. (MAG 4)
She was also described in her youth as "...beautiful, but like a shark was beautiful," by Eric Delano. (MAG 154)
Mary is descended from Albrecht van Closen through his descendant Elsa von Closen, who moved to England and in 1920 married Michael Keay. The couple had a daughter, Mary Keay, in 1924. (Whether this is the Mary Keay is unclear as, in MAG 62, Mary states she was 9 years old in 1955.)
Sometime before 1955, her father committed suicide by slitting his throat with a straight razor, which was left to Mary. Mary claims this was the only good thing he ever did for his family. (MAG 62) Mary's mother worked part-time for the Magnus Institute, which did not pay well enough to support the family; she also worked at a factory on Globe street to make ends meet. In her spare time, she instructed Mary on her "true studies," and young Mary spent much of her time scouring secondhand and antique shops for paranormal artefacts.
In 1955, Mary started watching Dr. Margaret Tellison, a doctor who lived near her and had her practice in her house, noticing that she seemed to have an aura of power around her. Dr. Tellison was a novelty in Mary's neighbourhood because she grew up in a Jewish neighbourhood, and Tellison was a gentile woman. Eventually, she saw the doctor murder an unnamed patient and write on their skin; later, she saw her reading from a book made of human skin and summon a spirit trapped within to ask them for their financial information. Mary was offended seeing that the doctor was only using her power to make money. Soon after, she committed her first murder, slitting the doctor's throat. She admits to Gertrude that she enjoyed watching the doctor commit the murder more than she enjoyed performing a kill herself. Mary stole the two paranormal books the doctor kept in her safe, the one made of human skin and used to trap spirits, and one full of poems about dying animals written in Sanskrit.
She spent the next several years mastering the Catalogue of the Trapped Dead and learned Sanskrit.
Her son, Gerard Keay, was born at some point in the 1980s, as he was in his late teens in or not long before 2002. (MAG 35) His father was Eric Delano, who worked in the Archives of The Magnus Institute. They met sometime between the late 1960s or 1970s near the beginning of her ownership of Pinhole Books and were married an unmentioned number of years later. He was murdered by Mary not long after their son's birth. (MAG 111) She murdered him by stabbing him with a pair of gardening shears and supposedly showed little remorse. She was said to be "slow and steady and focused", not making any comments as she killed him, according to Eric's entry in the book he was bound in. She was stated to often summon him out of the book after his death and used him to bounce ideas and plots off of. (MAG 154)
At some point, Mary opened 'Pinhole Books,' a shop in Morden, London that specialized in rare and antique books. Gerard referred to this as her "day job"; she also had another "vocation" that involved the supernatural and meeting with supernatural creatures. Both jobs required frequent travel.
Jurgen Leitner first visited Pinhole Books in 1993. He is known to have purchased several books from Mary, including the dead animal poem book.
Sometime in 2008, she was found dead of a supposed overdose; although she had been partially flayed. Pieces of her skin were hanging nearby, covered in Sanskrit. Gerard was tried for her murder, but he was acquitted when an important piece of evidence was ruled inadmissible.
As explained by Gerard in MAG 111, Mary's death was self-inflicted, as she died while attempting to complete a ritual to take control of the Catalogue of the Trapped Dead. After Gerard's arrest, Mary manifested and somehow removed the book from the evidence lockup, while contaminating all the rest of the evidence against Gerard. Through this ritual, she was able to project herself into the world, and "continue her work."
Pinhole Books closed officially after her death.
In 2012, Dominic Swain came into possession of the book Ex Altiora. Eventually, he found Pinhole Books which was staffed by an old woman with a shaved head and sporting numerous tattoos of words all over her body. (MAG 4)
Bold marks episodes where Mary has made a statement.