The Unknown Soldier better known as Vance Collins was a civil war Confederette soldier.
In life he and his brother Corporal Collins fought on opposite sides of the war. Corporal Collins shot Vance and with Vance's dying breath he swore vengeance. Years later his brother consumed with guilt dug him up from the battle field and brought him home. Though it's unknown how Vance came to be called The Unknown Soldier.
In modern times Vance became a specter a spirit that posseses the living and makes them act out what ever grudge they may have no matter how small. Sam, Dean and Garth salt and burn his bones but its not enough to put him to rest as he is tied to his stolen Indian Head Penny. After possesing Dean and trying to kill Sam, Garth melts down the penny, putting him to rest.
- There are similarities with his story line and the Supernatural novel Supernatural: The Unholy Cause. Such as the civil war reenactment references. The theme of betrayal was also used in the book as well.