She was described as being tall, with long, straight auburn hair, and eyes that "trapped you like a deer in the headlights."
Agnes' mother Eileen was a member of the Cult of the Lightless Flame. When the Cult decided to create a messiah, a chosen one to usher in the Scoured Earth, Eileen volunteered. She was five months pregnant, and had already taken care of Agnes' father in "the usual manner". Some objected, because Agnes had not been "conceived of the flame", but since no one knew how that would even work, they decided it would have to be enough for the child to be born in flames.
The Cult burned down 5 acres of forest to create the site of Agnes' birth. They built a pyre and laid Eileen down on it. As Eileen went into labor, they set her on fire, and when the flames burned down, all that was left was baby Agnes, lying peacefully in the ashes of her mother, untouched.
Agnes' childhood was difficult. She was prone to fits of violent rage, she could not be allowed near other children or left alone for any length of time. She even killed members of the Cult in her temper. Eventually she settled down and her strength grew. Some member of the Cult believed that Agnes should interact with normal children. Eventually, Agnes was sent to live at Hill Top Road (MAG 139).
In 1965, when she was said to be eleven years old, a young Agnes showed up with Raymond Fielding at his halfway house on Hill Top Road. She was introduced as his daughter and stayed with him there until 1973, when the house burned down (MAG 8). There was no sign of Agnes during the house‘s destruction, but in the basement was Raymond's badly burnt body, missing a hand. Agnes was responsible for the destruction of the house, although somehow she remained tied to it after its destruction (MAG 139).
Jack Barnabas visited the Institute to give a statement regarding a short-lived courtship he had had with Agnes during 2006 (MAG 67). In his statement, he explains first meeting Agnes in Canyon Cafe, and being immediately drawn to her. Agnes would come into the cafe every Tuesday at 3:00, sit alone with a black coffee, and never drink it. Whenever she left, the untouched coffee remained scalding hot.
Barnabas recalls a man trying to flirt with Agnes once in the cafe. The man began to sweat as he spoke to her, and eventually knocked Agnes's coffee over and onto his own hand; his flesh was immediately burned red despite the coffee having sat for well over the time it should have cooled. There was also a scorch mark on the chair Agnes had been sitting, although Barnabas admits he did not make the connection.
In late 2006, Barnabas sees seeing Agnes talking to an Asian women with a tattoo of a man wreathed in flames (later revealed to be Jude Perry (MAG 89). The woman spoke to her about a "job," one Agnes apparently declined. Despite this, the woman handed Agnes an envelope full of what was assumed to be money and left.
A week later, Jack Barnabas asks Agnes out on a date. It was only after she had left that he realizes he hadn't made any plans to meet. Despite that, Agnes shows at his door the next day with no preamble, and said they were going to the park. While at his flat, Agnes burns up a spiderweb hanging in the corner.
While on the date, she asks Barnabas if he has a destiny. When he says he does not, she replies with "That must be nice."
During a later date, Agnes suddenly gasps in pain, makes a phone call and mentions "a tree falling" and that they "need to finish something." When Barnabas escorts her home, there is a group of people surrounding her flat. Agnes tells him that she is sorry, and goodbye. Barnabas asks if he can kiss her, and when she takes his face in her hands, his skin immediately starts to burn and blister. It is implied Agnes sheds a tear over harming him.
Barnabas says that, after he awakens in hospital, the police inform him that Agnes is dead, and that they have ruled her death as suicide.