Christopher Heyerdahl (born September 18, 1963) is a Canadian actor who portrayed Alastair in Supernatural, the Wraith Todd in Stargate Atlantis, Sam in Van Helsing, "Swede" in Hell on Wheels, and Marcus in The Twilight Saga. Heyerdahl was born in British Columbia, and is of Norwegian and Scottish descent. His father emigrated from Norway to Canada in the 1950s. Thor Heyerdahl was his father's cousin. Heyerdahl also speaks Norwegian and studied at the University of Oslo. Heyerdahl is primarily known for his recurring role as the enigmatic and sinister "Swede" in AMC's Hell on Wheels. This post-American Civil War drama debuted as the second highest rated original series in AMC history. He is also known for his role as Leonid in the Are You Afraid of the Dark? episode "The Thirteenth Floor" and as Nosferatu in the episode "Midnight Madne...