Edward Durbin II was an American Man of Letters.
Edward was inducted into the Men of Letters organization in 1939, and became part of a small delegation that was sent to Europe to act as representatives for the American branch.
At some point Edward had a daughter named Maura, whom he taught a few magic spells. For reasons not yet told, Maura never joined him in the organization. She eventually married and had a child of her own, Eileen.
Edward was likely killed along with most of the members of the organization in 1958 by Knight of Hell Abaddon. 28 years later, his daughter and son-in-law were killed by a Banshee. His granddaughter survived, and spent most of her life trying to track down this particular Banshee and avenge her parents.
Eileen was aware that her grandfather was part of a secret though defunct organization. She would eventually meet Sam and Dean Winchester, who were legacies like her. Together they would kill the Banshee and continue on where the American Men of Letters left off.
Unfortunately, Eileen was attacked and killed by the British Men of Letters, who sought to eradicate the American hunters.