Mark Campbell was the distant cousin of Sam and Dean Winchester. Mark Campbell was raised a hunter and it is unknown where his parents were.
Background[]
Season 6[]
Mark was hunting with Christian Campbell, Gwen Campbell and Samuel Campbell, his cousins. Although he did not talk very often, when he did, it was something of distinct importance. Dean badgered on him for his lack of common conversation.[1]
He was killed by the Alpha Shapeshifter when it snapped his neck.[2]
Season 11[]
In Alpha and Omega, Mark is listed as one of the Winchesters' cousins on Lady Toni Bevell's wall alongside Gwen and Christian. All three are listed as deceased on the wall.