Dominic Lehne

He was a priest at St. Mary's Convent.

Background
One night in 1972, he was preparing to close up St. Mary's Convent in Ilchester, Maryland for the night, when the Demon Azazel appears as smoke, catches the priest off guard, and possesses him.

The following day, the possessed priest tells a group of eight nuns about his perspective on Lucifer's fall and imprisonment. He also tells them that "I feel, in a very literal sense, that I have been wandering the desert for years" searching for the devil. And that he has found the opening to his prison. The possessed priest locks the nuns in the sanctuary and slaughters them. He then places one inverted body on the altar, and pleads for Lucifer to "whisper through the door". Lucifer obliges, speaking through the dead nun's mouth. Azazel asks how he can free him. Lucifer says that Lilith can break the seals, and tells Azazel to find "a special child. A very special child." This is the beginning of Azazel's project with the Special Children, of which Sam is an end product.

When the priest is dispossessed, he remembers the demon's name: "Azazel". His account is recorded in the local newspaper that Sam reads to Ruby.

It is possible that the Priest is still alive. However, he'd likely be sixty to seventy years old.