Thomas Gregory

He is a priest who was killed on the church staircase for his keys. He comes back as a vengefuly spirit, but thinks hes an angel.

Background
After his death, he began appearing to people who were drug addicts and had nothing else to live for. He would appear and tell them to wait for a sign. When they see the sign, thses people would kill their target. He is first mentioned to Sam and Dean by Father Reynolds. When they go to visit his grave, Thomas comes to Sam. Besides Sam passing out and seeing Thomas, Dean discovers a certian plant around the grave which inticates a vengeful spirit.

Later on Sam summons Thomas's spirit to prove whether or not its angels. To his disappointment, its just Thomas. Father Reynold though is surprised and yells at Thomas for whats hes done. Thomas strongly believes hes an angel, but is put to rest by Father Reynolds. Although, all the people he targeted were people who doing evil acts (ie. Murder, Rape, 40 year old talking with 13 year old).

Note

 * The idea of angels is introduced here, and Dean tells Sam angels aren't real.