Luther was a vampire that appeared on the episode of Supernatural "Dead Man's Blood". He was the leader of a pack of vampires who kidnapped people to eat and recruit. He has a vendetta against Daniel Elkins because Elkins killed his family, but he was attempting to keep a low profile so he never got revenge on Elkins.
His mate Kate, stole the Colt, a gun made by Samuel Colt to kill the Supernatural. As such Sam, Dean and John Winchster tried to get it back and stop the vampires. As part of the plan, John kidnapped Kate. He led the other Vampires after them. He was killed when John Winchester shot him in the head with the colt.
He was the first supenatural creature to be killed by the colt.